UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

The cataloytic preparation of ether from alcohol by means of aluminum oxide Graham, William Ernest 1925

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-ubc_1925_a7_g7_c2.pdf [ 3.07MB ]
Metadata
JSON: 831-1.0061834.json
JSON-LD: 831-1.0061834-ld.json
RDF/XML (Pretty): 831-1.0061834-rdf.xml
RDF/JSON: 831-1.0061834-rdf.json
Turtle: 831-1.0061834-turtle.txt
N-Triples: 831-1.0061834-rdf-ntriples.txt
Original Record: 831-1.0061834-source.json
Full Text
831-1.0061834-fulltext.txt
Citation
831-1.0061834.ris

Full Text

THE CATALYTIC PREPARATION OF ETHER  BY MEANS OF ALUMINUM OXID by William Ernest Graham 0O0  A Thesis submitted for the Degree of MASTER OF APPLIED SCIENCE in the Department of CHEMISTRY 0O0  THE CATALYTIC PREPARATION OF ETHER FROM ALCOHOL BY MEANS OF ALUMINUM OXIDE by William Ernest  Graham  0O0  A T h e s i s s u b m i t t e d f o r t h e Degree of MASTER OF APPLIED SCIENCE in t h e  Department of  CHEMISTRY  0O0  The U n i v e r s i t y of B r i t i s h  Columbia  APRIL 1 9 3 5 .  CUMA^V^XL  TABLE OE CONTENTS. INTRODUCTION. APPARATUS AND PROCEEDURE. METHOD OP ANALYSIS. PREPARATION OP CATALYSTS AND REAGENTS. Reagents. Catalysts. Note on t h e Washing of Aluminum Hydroxide P r e c i p i t a t e s . CALCULATIONS AND ACCURACY OP RESULTS. RESULTS AND DISCUSSION. D e h y d r a t i o n of A l c o h o l t o  Ether.  Effect  of R e - r u n n i n g t h e P r o d u c t s .  Effect  of T e m p e r a t u r e o n ' t h e  Effect  of T r a c e s of A l k a l i on C a t a l y t i c  D u r a t i o n of C a t a l y s t  Reaction. Aotivity.  Life.  F o r m a t i o n of A l c o h o l from E t h e r and W a t e r . Heat of R e a c t i o n and Thermal D a t a . D i s c u s s i o n of V a r i o u s C a t a l y s t s f o r SUMMARY. CONCLUSION  BIB110 GRAPH Y.  c»mm«co'"l ftipetti.  Ether Production.-  THE CATALYTIC PREPARATION OF ETHER PROM ALCOHOL BY MEANS OP ALUMINUM OXIDE.  INTRODUCTION. Considerable work has been done on t h e d e h y d r a t i o n of a l c o h o l in t h e gaseous phase by means of s o l i d c a t a l y s t s . Jhe c a t a l y s t s which have been used have been of many types* b u t m e t a l l i c o x i d e s have found t h e g r e a t e s t f a v o r , and of t h e s e alumina appears t o be the most e f f i c i e n t  and t h e  most widely employed. In t h e dehydration of e t h y l a l o o h o l alumina beoomes a o t i v e a t t e m p e r a t u r e s above 3 0 0 ° c , " g i v i n g i n c r e a s i n g amounts of e t h e r with i n c r e a s e of t e m p e r a t u r e .At 350° the y i e l d of e t h e r i s high and r e a d i e s a maximum value*for  as  t h e t e m p e r a t u r e i s r a i s e d s t i l l f u r t h e r * i n c r e a s i n g amounts of e t h y l e n e begin t o be formed and t h e y i e l d of e t h e r  is  cut down a c c o r d i n g l y .Above 300 t h e p r o d u c t of d e h y d r a t i o n 1,2. i s mainly e t h y l e n e . Pure e t h e r is»also,dehydrated r e a d i l y t o e t h y l e n e a t , a n d above 350.There i s some d i f f e r e n c e of o p i n i o n among the d i f f e r e n t  workers as t o the mechanism of  t h e s e r e a o t i o n s . T h e dehydration of a l c o h o l t o e t h e r and e t h y l e n e may ooour in two independent s t e p s : 3 C2H;50H—•*• (CsH 5 ) 2 0  + H 3 0,and C.H OH - > C H +- H30 . T h i s , Sender ens  c o n s i d e r s t o be t h e mechanism.The d e h y d r a t i o n t o e t h y l e n e 1 Senderens,Ann.Chim.Phys.,(6) 35,505 ( 1 8 1 3 ) . 3 I p a t i e w , B e r . , S 7 , 3886 ( 1 8 0 4 ) .  3  may occur in two s u c c e s s i v e s t e p s however t (CjgH^sO +• H 2 0,and ( C j O ^  3 c2H-0H —>  -*> CgH^ +• HgO .Ipatiew concludes  t h a t the l a t t e r i s t h e mechanism. Pease and Yung° consider t h a t i t i s n o t n e c e s s a r y t o p o s t u l a t e e i t h e r of t h e two mechanisms t o t h e Sxolusion of t h e o t h e r .Prom t h i s  investi-  g a t i o n r e p o r t e d h e r e w i t h i t would seem q u i t e p r o b a b l e t h a t t h e r e a c t i o n prooeeds according t o both mechanisms simultaneously. Ipatiew* working a t high t e m p e r a t u r e s and p r e s s u r e s * w i t h aluminum oxide has dehydrated a l o o h o l to e t h e r and e t h y l e n e and furthermore has shown t h e r e a c t i o n t o be r e _ v e r s i b l e , having o b t a i n e d an a p p r e c i a b l e amount of a l o o h o l from equimoleoular q u a n t i t i e s of e t h e r and water .Sender ens, as r e s u l t of c o n s i d e r a b l e work*has r e p o r t e d a good yieldcff e t h e r from a l c o h o l by means of aluminum oxide p r e p a r e d by d e h y d r a t i n g t h e hydroxide p r e o i p i t a t e d from s o l u t i o n s of sodium aluminate by means of s u l p h u r i o aoid.He c o n s i d e r s t h i s form of alumina b e t t e r t h a n t h a t o b t a i n e d by p r e c i p i t a t i n g the hydroxide from s o l u t i o n s of aluminum s a l t s by means of ammonia. Mailhe and de Godon were  abie  t o get  a 71$ y i e l d of e t h e r a t ISO0 u s i n g anhydrous aluminum s u l p h a t e as c a t a l y s t .They showed t h e influenoe of  increasing  t h e amount of o a t a l y s t by o b t a i n i n g higher and higher y i e l d s .Pease and Yung r e p o r t a 60$ y i e l d of e t h e r at 250° with alumina p r e p a r e d from aluminum n i t r a t e and ammonia. I t i s g e n e r a l l y aocepted»in f a c t almost e s t a b l i s h e d , 3 Pease and Yung>J.Am.Chem.Soo.,46,390 (1934) 4 l a i l h e & de Godon,Bull.eoo.chim.,35,565 (1916)  5 that the r e s u l t s of c a t a l y s i s are due to reactions taking place at surfaoe of the catalyst  material in the case of  heterogeneous systems .Older theory p o s t u l a t e d the formation of definite intermediate chemical compounds which are un_ s t a b l e and break down to give the reaction produots.This, Senderens considers to be the case in t h i s reaction* a oomplex involving one moleoule each of alumina and alcohol being formed which may break down d i r e c t l y to give ethylene or which may r e a c t with another molecule of alcohol to give ether .The more recent explanation i s that catalys i s i s the r e s u l t of the molecules being brought into p o s i t i o n for reaotion as a r e s u l t of adsorption on the surface of the catalyst .Moleoular a t t r a c t i o n of every degree between t h a t of d i s t i n o t chemical combination and that of loose adhesion i s considered to e x i s t . I n either oase i t i s e a s i l y believed that the extent of the surface of the c a t a l y s t w i l l p l a y a considerable part in the activation of the r e a c t i o n . JJpie idea that the spacing of atoms or moleoules would be a f a c t o r in o a t a l y t i o reactions at surfaces was f i r s t spoken 5 of by Langtnuir . Experimental evidence of t h i s has l a t e r been given by Adkins  who has been able to s e l e c t i v e l y  a c t i v a t e alumina for specifio r e a c t i o n s by r e g u l a t i n g the s i z e of the i n t e r s t i c e s in the maleoules, or pores of molecular dimensions in the oxide .Senderens considers the alumina prepared from sodium aluminate more aotive than dehydrated c o l l o i d a l alumina.This difference may be explained as due to a difference in s t r u c t u r e , a s the former p r e c i oLangmuir , Trans .Far,Soo., 17 .617 (1922) through C,A.16,7(193#) 6 Adkins, J.Am. Chem.Soo., 44,265,3175 (1933) ;45, ISO (1934)  4 p i t ate i s d e f i n i t e l y c r y s t a l l i n e and the l a t t e r amorphous. , Prom a consideration of the above i t would seem highly p o s s i b l e to obtain a c a t a l y s t more aotive in ether formation than any h i t h e r t o prepared. The purpose of t h i s inve st i gat icn was to determine the catalyst most effioient in the production of e t h e r . Different c a t a l y s t s have been prepared in ways which would give p r e c i p i t a t e s of differing n a t u r e . The investigation i s considered to have been quite successful. It has been mentioned t h a t work on t h i s problem has been done by Pease and Yung,During the oourse of t h i » i n v e s t i g a t i o n two papers ' on t h i s reaction appeared by them.In t h e former they reported a maximum yield of 60$ dehydration t o ether at 350°C.In the l a t t e r paper were given data for an equilibrium in the ether-alooho 1-water reaotion showing a maximum possible conversion of alcohol to ether of 62$ at 375°.Calculations from the data given by them show the equilibrium to correspond to a maximum conversion of l e s s than 66$ at 350 .The r e s u l t s of our work show yields considerably higher than t h i s with several c a t a l y s t s as will be f u l l y demonstrated l a t e r : we have obtained yields of over 60$ at 350 .The r e s u l t s of Senderens work undoubtedly show yields higher than 66 $ but Senderens i s indefinite as regards d e t a i l s . This faot i s indicated by a separation of the product into layers and Pease and Yung s t a t e t h a t the products they obtained did not separate into 7 (a) van Br enamel en, Re c .trav.chim., 7,75(1668) ; - (b) Martin,Mon.Sci.,(5) 6,335. (1.915) through Ch.Abst ,10,571. 8Pease and Yung, J.Am.Chem.Soo .,46,3397 (1934)/  o  layers.These f a c t s indicate that the equilibrium in the reaotion cannot be where Pease and Yung have placed i t .That the r e a c t i o n is»however,reversible i s undoubtedly the oase. It was f i r s t shown by Ipatiew and has also been shown in t h i s investigation. As an explanation for the disagreement in equilibrium / values such as i s shown her&ithe idea has been presented that a shift in equilibrium may be brought about by a s o l i d c.  c a t a l y s t .The idea has been mentioned by Bancroft" and Edgar and Sohuyler  s t a t e that t h i s explanation was offered at  the Roohester meeting of the American Chemical Society in April 1931 to account for certain anomalies in e s t e r i f ioation e q u i l i b r i a presented in a paper by Reid and Mulliken.There i s no good evidence for such a viewpointjjiowever. In determining t h e i r equilibrium data Pease and Yung have made determinations at lSO° U sing sulphuric acid as a catalyst and at 375° using alumina.The work of Edgar and Schuyler on e s t e r i f ioation e q u i l i b r i a show t h a t the equilibrium in the gaseous phase may be higher than in the l i q u i d phase and they oonolude that the e q u i l i b r i a are in general not the same .From t h i s i t i s open to question whether the data of Pease and Yung are oonparable in the two oases. Another point worth notice i s that we have always obtained small amounts of ethylene,and the fact t h a t t h i s reaction i s also catalyzed complicate* the oase .Pease and Yung claim t h a t in t h e i r e q u i l i b r i a determinations no apprec i a b l e amounts of ethylene were formed.This would indicate 9 Bancroft,J.Phys.Chem.,31,603,(1917) 10 Edgar and Sohuyler,J.Amer .Chem.Soc, 46,64 (1934),  6 t h a t t h e alumina o a t a l y s t used in t h a t case was n o t very a c t i v e , a s at 2?5  the ethylene reaotion is o r d i n a r i l y c a t a -  l y z e d s t r o n g l y . They s t a t e t h a t t h i s c a t a l y s t was not as a c t i v e as t h a t used in t h e k i n e t i o measurements of t h e i r f i r s t p a p e r . With t h e method of a n a l y s i s a v a i l a b l e i t would be r a t h e r u n s a t i s f a c t o r y t o attempt t o determine t h e e q u i l i b r i u m p o i n t of t h e r e a c t i o n o t h e r t h a n a p p r o x i m a t e l y . APPARATUS AND PROCBEDURE. In c a r r y i n g out t h e experiments a flow method has been u s e d t h r o u g h o u t . The arrangement of t h e a p p a r a t u s i s shown in P i g . l with t h e furnace in p o s i t i o n and in F i g . 3 with t h e furnaoe removed. The p r o c e e d u r e c o n s i s t e d in p a s s i n g a d e f i n i t e volume of l i q u i d a l c o h o l i n t o a hot tube f i l l e d with t h e  catalyst.  The a l c o h o l v a p o r i z e d on c o n t a c t with t h e hot s u r f a c e of t h e t u b e . The vapors then p a s s e d on over t h e o a t a l y s t and out through a condenii* »the l i q u i f i e d produot s being d e t a i n e d in a b u l b a t t a c h e d to t h e condenser and t h e gases p a s s i n g o v e r t o an a s p i r a t o r c o n t a i n i n g a s a t u r a t e d sodium c h l o r i d e  solution.  Before a run was made f o r a n a l y s i s about 15 o o . of a l c o h o l were p a s s e d over t b e o a t a l y s t t o make sure t h e  latter  was*in a steady s t a t e d u r i n g t h e r u n . S e v e r a l methods were t r i e d f o r i n t r o d u c i n g the a l c o h o l i n t o t h e r e a o t i o n t u b e . The method used must be such t h a t the a l c o h o l oan be p a s s e d over t h e c a t a l y s t a t a c o n t r o l l e d s t e a d y r a t e . Sealed connections were used wherever p o s s i b l e and in other oases c o r k s were used i n s t e a d  of  7  l u l l fUillilllUluil FigJ[ -  ft  Apparatus with furnaoe in p o s i t i o n .  P i g . 3 _ Apparatus with furnace removed,showing connections with o a t a l y s t tube*  8  rubber connections on account of the sulphur content of thB latter. In the f i r s t experiments a heating element was used to pass alcohol vapor into the tube.The f i n a l form of t h i s vaporizer consisted of a glass bulb with platinum heating c o i l with leads sealed through the glass,and d e l i _ very and f i l l i n g tubes sealed on.The vaporizer method has the following disadvantages: The apparatus must be disconnected after every run»with possible l o s s of aloohol vapors; the r a t e of vaporization i s not e a s i l y controlled c o n s i d e r able time i s required in heating the aloohol to b o i l i n g and t h e vaporizer must be oooled after eaoh run for weighing. I t was decided to t r y a method of introducing the aloohol from a graduated vessel and allowing the vaporizat i o n to take plaoe in the hot c a t a l y s t tube.Adkine oonsiders t h a t vaporization of the r e a o t a n t s by dropping on hot surfaoes unsatisfactory but we have found i t to be quite s u i t a b l e for a v o l a t i l e substance l i k e e t h y l aloohol.The apparatus was arranged as follows: A o a p i l l a r y tube bent at r i g h t angles was sealed on to the top of  a  b u r e t t e ; a side  tube bent upward at right angles was sealed into the burette near the t o p ; a dropping funnel with a o a p i l l a r y tube stopcook sealed on at the end of i t s stem was i n s e r t e d into the side tube of the burette through a corkja seoond dropping funnel was sealed into the burette n e a r the top for r e f i l l i n g with aloohol,The o a p i l l a r y -tube was introduced into the furnace .Mercury was allowed to drop at a controlled r a t e  s from the dropping funnel into the burette foroing the alcohol into the c a t a l y s t chamber .The length of mercury column was about 45 cm.and the rate of flow was e a s i l y c o n t r o l l e d by r e g u l a t i n g the stop_oook .The flow i s easier to control if the edges of the hole in the stopper are scraped back a l i t t l e .The r a t e of flow for a short column of mercury was found to be d i f f i c u l t to control,The amount of alcohol passed over the c a t a l y s t was read off from the b u r e t t e . This apparatus oould be left connected to the furnace for several runs,fresh alcohol being introduced i n t o the burette by drawing off the mercury at the bottom and allowing fresh aloohol t o run in at the top .This method was very e a s i l y controlled and quite s a t i s f a c t o r y . The o a t a l y s t mass was ground up and spread along a pyrex tube about 1.6 cm.in diameter»almost f i l l i n g i t for a length of 120 cm.A small o u t l e t tube was sealed on one end.The oatalyst tube was s l i g h t l y longer than the h e a t i n g furnace and was placed inside the heating element of the l a t t e r . The fumaoe was e l e c t r i c a l l y heated,It consisted of a 1 1/4" iron pipe insulated with a thin sheet of asbestos and wound with nichrome resistance wixe.The early experiments were oarried out in a SO" furnace>but l a t e r a 54* furnace was constructed to permit the use of more c a t a l y s t .Concentric with the iron pipe was a 5" stove pipe jacket*the two pipes being held in place by means of two asbestos board p l a t e s with convenient grooves turned in  10 them to f i t over the pipes,and a hole in the centre of eaoh to allow the i n s e r t i o n of the reaction tube.The temperature was measured by a thermometer placed between the reaction tube and the iron pipe .This was more convenient than one in t h e oatalyst tube and on t e s t was found to r e g i s t e r sensibly t h e same temperature»particularly so when the furnace was in a steady state.With a large furnace such as t h i s , t e m p e r a t u r e r e g u l a t i o n was quite easy. On aocotint of the v o l a t i l i t y of ether an e f f i c i e n t condenser was a prime r e q u i s i t e .TEo get the most accurate r e s u l t s in weigh-in® the condensed products, the condenser and r e c e i v i n g vessel were made in one pieoe and as l i g h t as possible .A s p i r a l of glass tubing was sealed into a bulbj a s t r a i g h t v e r t i c a l tube was sealed on to allow the escape of ethylene to the aspirator and act as a reflux condenser for any entrained ether vapor .The expansion of t h e gas into the bulb helped to condense the ether and only.negligible amounts escaped,The condensate was removed through a stop-cook at the bottom .The ethylene was oolleoted over s a t u r a t e d sodium chloride solution which was soon s a t u r a t e d with the gas and served quite well.The pressure was kept almost at atmospheric .The condenser was kept in a ooId bath and only in exceptional case3 when the ethylene y i e l d was high was any appreciable amount of ether c a r r i e d over with the gas.  11  METHOD OP MALY8IS. Considerable d i f f i c u l t y was encountered in g e t t i n g a s u i t a b l e method of a n a l y s i s . T h e l i t e r a t u r e on t h e  subject  was of l i t t l e a v a i l .Some work was done on a method of d i f f e r e n t i a l o x i d a t i o n of e t h e r and a l c o h o l with u n s a t i s . f a o t o r y r e suit a. Pease and Yung in t h e i r p a p e r s on t h i s r e a o t i o n made use of a s a l t i n g out method of d e t e r m i n i n g e t h e r  in  m i x t u r e s of ether , a l c o h o l and water.They show a ourve f o r t h e c o r r e c t i o n which i t i s n e c e s s a r y to apply t o the o b s e r v e d volume of e t h e r s e p a r a t i n g out from t h e mixture when t h e l a t t e r i s shaken up w i t h s a t u r a t e d s o l u t i o n ef sodium c h l o r i d e in t h e p r e s e n c e of an exoeas of t h e s o l i d s a l t . I t was found impossible t o get r e s u l t s t o oheok with t h e h a l f of t h e i r curve c o r r e s p o n d i n g to lower p e r c e n t a g e s of e t h e r . I t was found t h a t t h e amount of e t h e r  separating  depended on t h e r a t i o of e t h e r t o a l c o h o l and on t h e r a t i o of volumes of t h e sample analyzed and t h a t of s a l t  solution.  The disagreement w i t h t h e i r curve may have been due t o t h e composition of t h e m i x t u r e s d e a l t w i t h , a n d since Pease and Yung used l a r g e r amounts of a l c o h o l in t h e i r r u n s than i t was d e s i r e d t o use h e r e , o r than were n e c e s s a r y for  acouracy*  i t was found n e c e s s a r y t o oompile d a t a based on m i x t u r e s of t h e same t o t a l volume and c o n t a i n i n g e t h e r , a l c o h o l and water in n e a r l y t h e same p r o p o r t i o n s as would be o b t a i n e d from t h e c a t a l y s t t u b e . T h i s was a l l t h e more n e o e s s a r y  13 ainoe with the most aotive c a t a l y s t s the products separated into two layers in which case the e n t i r e product would have to be taken in the analysis.This l a t t e r faot eliminated altogether a method of analysis by specific g r a v i t y determination, A method of analysis based on the above was worked out in t h i s laboratory by Miss A.(J.Winter.11 The problem was attacked as follows: A s e r i e s of determinations with mixtures of known composition corresponding to d i f f e r e n t percentages of conversion of an o r i g i n a l volume of 30 oo .of alcohol was made and  a  curve p l o t t e d showing  t h e correction necessary to be applied to the volume s e p a r a t i n g when the mixtures were shaken up with 100 oo. of saturated s a l t solution .An excess of solid salt was always present as some was always displaced by the alcohol in the mixture. These mixtures were made up by volume at 15°C.and contained ether,alcohol and water in the propor, t i o n s in which they would occur in the products from the dehydration of alcohol .Sinoe the volumes of ether,aloohol and water mixtures are very nearly the same as the volume of the alcohol equivalent as shown by the specific gravity t a b l e s of Sanfourche and Boutin 12the method could be d i r e c t l y applied t o t h i s work.To allow for a s l i g h t conversion t o ethylene a small excess of alcohol was passed over the oatalyst .The r e s u l t ing product would contain a l i t t l e more water than the equivalent of the ether .Test determina11 Miss Winter,The s i s submitted for the degree of B.A.,at fhe University of B r i t i s h Columbia, Apr i l 1935. 13 Sanfourche and Bout in»Bull .Soo.Chim.T i). 51,456,(1933) through Pease and Yung»ref . 3 .  IS t i o n s were therefore made with mixtures containing small amounts of added water but showed no difference in ths amount of ether separating. Mixtures in which the volume of ether was kept constant and t h a t of the alcohol varied gave no appreciable r e l a t i v e change in the necessary correction.The method i s acourate to Vjo for mixtures having the composition of those for which the data were compiled. The mixture to be analyzed (30 c c . i n volume) was shaken up with a saturated sodium chloride solution in a 100 oo.volumetric flask to which a burette stem had been sealed close to the bulb,The mixture was kept in a bath at 10° and repeatedly shaken u n t i l the volume separating became constant. A curve i s given (Pig.o) from the data t a b u l a t e d vTable 1) showing the observed volume separating at 10° against the t r u e volume at 15° .There was no 103s of e t h e r when the flask was well corked and kept in the cold bath.The design of1 the condenser enabled transfer of the products to the flask to be made with a minimum escape of vapors.The method i s very convenient owing to the short time required for a determination. The method may be used as a rapid approximate method for the d e t e r m i n a t i o n , ^ , e t h e r in mixtures of composition d i f f e r i n g from those for which the data are given .The e r r o r i s considered to be within 2$ in the extreme f o r such cases and for the moat p a r t within 2 fo. The method becomes inexact however»in a l l cases,when the volume of the e t h e r becomes l e s s than Z>0/o of t h a t of the alcohol.  14 Table  1.  C o m p o s i t i o n of m i x t u r e , 1 5 °  Volume  Ether  separating  Alcchol  CO .  Water  cc.  cc.  s.t  16.5  1.5  3.00  3.8  15.05  1.25  U.S  4.00  3.5  15.1  1.3  13.6  5.7  3.3  11.7  1.1  10.7  fc.o  1.6  S.6  1.1  8.9  10.0  1.5  7.S  1.0  6.9  13,0  1.35  6.0  0.9  5.3  1S.6  o.s  4.5  O.S  3.8  15.8  0.6  1.3  3.1  17 .8  cc. 0.00  16. 5  oc.  Correction  PREPARATION OP CATALYSTS AND REAGENTS. ALCOHOL: 9 5 $ a l c c h o l was r e f l u x e d o v e r l i m e and d i s t i l l e d a n d was i n a l l c a s e s p r a c t i c a l l y a b s o l u t e . I n some of  the  e a r l i e r work a b s o l u t e a l c o h o l a s p u r c h a s e d from Malldinckrodt C h e m i c a l Worlds was u s e d . Ether:  The e t h e r u s e d was Merck 1 8 a b s o l u t e e t h e r  o v e r sodium  distilled  .  The s p e o i f i o  g r a v i t i e s of t h e e t h e r and a l c o h o l were  d e t e r m i n e d a t 15° and c a l c u l a t i o n s made from t h e s e Specific  values.  g r a v i t y of t h e a l c o h o l was .7S5 and of t h e e t h e r  CATALYSTS: In t h e e a r l y p a r t of t h i s i n v e s t i g a t i o n found q u i t e easy to p r e p a r e a c a t a l y s t  a c t i v e in  f o r m a t i o n but which was n o t n e a r l y so a o t i v e i n  i t was ethylene  ether  ,712,  1  ;  -1  ->—+-rr  "  -;-hrrr  i  .  :;  ;! V  i ••••  1  t  .1 -  Ji:::  1  -  .  .  • !  •  LiLj  ;  h  ^ u._.  — TY) ~ i  '  1  —J""'  : :  1  1 " r  ' . ; ' ) • •  .  ••  •! » , ,  | :  i •  •  •  _l_ .  4  . -  w  '  - •  4  • ' • ! • •  _  •  . 1 ...  ;  —, j . :, ; ...... J.... - —J 4 — --  ;  •  •  •  ;  •  ;  -  ij/ -  ' • .  J' : ':' . • "  ;  ::  JL-+.-~ J  ___j ]  ,  _j :.  1 > ;  ••• i  i  \  >  !• ••  .i.  yM '••. I-'  *-4  rf-  -  -  —  -  •  — — •  :  ;  '  •  ',.!".  •i-l:.--!  •  -  !  —  ' —  - " • ! •  .  -  ' i  1  1  ;  '  i • t  ••-•  i  .,,,.  1 ":. /  i  •  -  :  .-I i  :  .j.  f  '"•  TT  I.  :  !•  ,  l.  True \Zofume ^ ' 9 - 5 . - Correction  Chart  4  ••'•  L 1| ';  1 ' ••-  l  __  f_-p-  i .'  i  '  • 1 '. L  . j.. ...  \  —„.^~.-;-  J.  + _..„,.  :  , „..... i  ..  1 1  .  ;::l:i:L: i ; 1K  i ..  —L t  •r  er  T i" !:'  ..••  _L—i i'+  in cc.at15 "C rer tth  ~  i  v  .3  ~  j:..U- 1 :  • • ! " •  ?  * — * • *  - -^-~~—— —  [••'::-  . , • ' • : ' .  i:..  - " ' ~  !  ! •  :;  i ~  ,  i  \  •  ! i : 1 iJ_;_;  i -'",;j  __^__j "j '  ;-..[,•.  ;  ^ L! 4  :LL.  1  Lr  ;  U  "'inl ! -  r- ~ r|-  :  j  i-  .,....)—  •: £  ]  •••  "r*h"^" •  / /:;  ... j . ,  !  *©:i-  :  :L  —-t—  r~  ,l  • 1  •  " j" 1 ".  \  :  j-.  ^r  -—f—a  ' ••• 1 ::  •  __J_  l....;.|...  iV  '. 1  .-  : : - — H — ^  . ' ; ' • * > •  K  j  •  - 4 - - * - -.-..!.  :  '•'•;'  i '  .. .  "1 ' :  • 1  '  „i .-. i -4.™„L_-  '":. j  •  !  ;  1  M !  [  1  1  !  • • "  -y£+r"~ -  f: "j it:  „.:;.;.,  ' . 1  <^  'i  '  -  ,  ,  1 ••]'•' "-  -"—1~  :  ;  ' i  "'  •  —r-TT—•  i?:  j  X  •;  •  T:  1  >4  ,.„_ _„_ L  . „  ••  '  •  -.I ' • ;  'j " i  —[•""" '. ...  i  j ,  ;'' i_.„ • T F v l  -  ;  4.  i  ....' *--.r  -. - j ™  • ' • • " > " • >  • 1  -  •  ..,  • ' ,  •'.!  i -i  ."••]-  Ml  j  • ' • ' L  r  '•"•• 1 '• T'"•"•  L  :  :I '  • ;  :  i 1—•-  •—  '•- i  .  ": I !  !  i  |-  • : ' • " •  ...-] . = .  -  : • -:j-'.  I  ; ! • : :  :  1  ,  '  :  !  ' \  |  p  ~|: . 1  ; . ! ( . • •  i  :  :  'J.:" 1 .'.••'. ir-  ;  •*—  i• •  i  . | -I  .'!.',  'I-  !"' r:;  •  •  ' •  • 1  j,  i  ". i . i  |  . „ . —n—, - '  L 44 .,['.. "I^_ [ 4 4 . s  W •  —j~-l  ""~1  i  j  . i . j ..'-'  ' -,-H-;-.-'  •1 '  i  ;  •!•'•••  •  ' I •  |  !.  .  -  j • •  !  ._].  !•• i l - ' . ' i  »f <«  '  .:i-::.  : 1 '  >  |  —i  •  j  * »*.  . i 1"  : j. ;  i  •  -1  .•I ,  ' • •  .  J~~ .  •  •  "—H  •  ' ' . ' . - -rLi-. -  j ...• i H— — ' r r - r -  )  .'  ; • : . : ! :  -••—1-~-  'i' i  !  •'!  • \  •  <Ta^  :  i  j  •i  "}•"  r-i i  ~t~'  •• j  •  .Hi:-  —  •  •  ~k  :  4|4  T  ;  L•-  :  !M~  -•']:.:  • i""'  TT-4-r-  :  '1  ::.•••]  ., '  "  • i •  J  ' L "' :  lEk  : !"'•]'  '  lW:  --j" '  —  *•*»  *  1  —[  ill;  !  ^—- *-*r  •  1  '  —^  j :  !  ..;]? •;  1  i • ..„„l.- r i' 1 :  '  r  1 :  •  1 ---Irt-rr'  • T  4_ •  f ""• j 1 •  L. i  -—1'.':.  r! :TT;.:  J  —4—:  j -  :, f'i:  ;! I '. ; TTri;.  —1  ~1—  ...ili—  Qetertninotion.  1 — __ .  lb  • " " ! !  •  15  format ion .Sinoe the purpose of t h i s work was to determine t h e best catalyst for e t h e r , c a t a l y s t s which gave large y i e l d s of ethylene at r e l a t i v e l y low temperatures- as under 260  _ were discarded and few quantitative measure-  ments made with them .Since a l l previous work shows the produots of alcohol decomposition over alumina at t h i s temperature to be almost e n t i r e l y ether or ethylene t h i s was considered a j u s t i f i a b l e proceedure and much time was aaved thereby. Of the alumina c a t a l y s t s used in alcohol dehydration t h a t prepared by p r e c i p i t a t i o n from a solution of an aluminum s a l t with ammonia seems to have been used most often .Senderens has however, shown t h a t alumina prepared from sodium aluminate by p r e c i p i t a t i o n with sulphurio aoid i s more active in ether formation,The p r e c i p i t a t e in the former oase i s quite amorphous while t h a t in the l a t t e r oase i s considered to be c r y s t a l l i n e . Both are r e a d i l y soluble in acids and alkalies.The hydroxides formed in these p r e c i p i t a t i o n s were dehydrated by heating to temperat u r e s not over 400°. In t h i s investigation the f i r s t c a t a l y s t s made were obtained by following the r a t h e r indefinite data given by Sendereas as olosely as p o s s i b l e . l t wa3 thought t h a t the most active catalyst would be obtained by increasing the surface of the p a r t i c l e s of the p r e c i p i t a t e .Accordingly the p r e c i p i t a t i o n was carried out in solutions of varying d i l u t i o n .An attempt was made to spread the p r e c i p i t a t e out  16", on a support suoh as glass wool from very d i l u t e s o l u t i o n s . It was further thought that the use of a very weak acid 3uch as oarbonio aoid would give a muoh finer p r e o i p i t a t e than s u l p h u r i c Some c a t a l y s t s were prepared by bubbling C03 through solutions of sodium aluminate.lt i s also known t h a t solutions of sodium aluminate in which the fcatio of AloO^ : Na.0 i s under 1:3 w i l l deoompose slowly on standing, due to h y d r o l y s i s , giving a c r y s t a l l i n e p r e o i p i t a t e of 15 aluminum hydroxide. C a t i l y s t s were prepared in t h i s manner .The p r e o i p i t a t e obtained by means of GOg from a 5$, o r s t r o n g e r , s o l u t i o n of sodium aluminate i s also of the same c r y s t a l l i n e nature .These p r e c i p i t a t e s were very insoluble in acids and alkalies.The p r e c i p i t a t e s with sulphuric aoid, while they may be c r y s t a l l i n e are evidently of a different s t r u c t u r e as they are r e a d i l y soluble in a c i d s . The following general information was gained in regard to the preparation of the catalysts.The p r e c i p i t a t e s adsorb impurities such as sodium s a l t s very strongly .Washing with hot water helps to remove the impurities but the p r e o i p i t a t e must not be boiled as t h i s coagulates the p a r t iolo s.Washing i s best carried out by means of deoantation as f i l t r a t i o n i s apt to contaminate the p r e c i p i t a t e with f i l t e r paper . Where f i l t e r i n g i s necessary a layer next to the paper must be scraped off and discarded.Pure water must be used and in t h i s work d i s t i l l e d water was used throughout . P r e c i p i t a t i o n from concentrated solutions with sulphuric 13(a) D i t t e , Compt.Rend., 116,165 (16S5) (b) Russ.:, Zt.Anorg.Chem.41,316 (1SG4)  17 a c i d gives a lumpy p r e c i p i t a t e , h a r d to wash.It was thought t h a t p u r i f i c a t i o n by means of d i a l y s i s might introduce some iarpurity from the membrane though such a method might have hastened washing.The temperature to which the c a t a l y s t i s heated in dehydration has considerable effect :the best r e s u l t s were obtained by heating the p r e c i p i t a t e to 400 G. Heating to higher temperatures i s apt to be injurious as i t tends to ointer the oxide .The p r e c i p i t a t e s on glass wool were not very a c t i v e , p o s s i b l y owing to contamination from the glass wool.These p r e o i p i t a t e s were not of the structure found to be the best for the r e a c t i o n . The preparation of the best c a t a l y s t s i s described in d e t a i l . Two different l o t s of sodium aluminate were used which w i l l be r e f e r r e d t o as I and II,Lot £ ooirtained 10$ moisture and considerable excess a l k a l i .Lot I I contained 18$ moisture and l i t t l e excess a l k a l i . Catalyst JL t  800 grams of sodium aluminate I were dissolved  in 1© l i t r e s of water .An equivalent amount of sulphuric acid in t h e same volume was allowed to drop slowly into the a l k a l i n e solution with constant agitation.The p r e c i p i t a t e was washed by decant at ion u n t i l the wash water f a i l e d to give a t e s t for sulphate and then f i l t e r e d . T h e f i l t e r oake wa3 then s t i r r e d up in nearly b o i l i n g water,deoanted two or t h r e e times and f i l t e r e d again.The p r e o i p i t a t e was then dried in an oven at 120° for about 24 hours,ground up and heated in the furnace t o about 250°.it was then considered ready for u s e . This oatalyst was successfully duplicated. The maximum yield obtained with i t was 74.5$.  IS Catalyst B :  1000 grams of aluminate I were dissolved in  18 l i t r e s of water and CO2 bubbled through the solution at a moderate r a t e u n t i l a l l the aluminum was p r e o i p i t a t e d as hydroxide .This point was determined by f i l t e r i n g a l i t t l e of the suspension and t e s t i n g the f i l t r a t e for aluminum. This p r e c i p i t a t e was oxrystalline and washed r e a d i l y . It was washed in cold water u n t i l i t f a i l e d to give a t e s t f o r a l k a l i with phenolphthalein and then f i l t e r e d and washed once with hot water .On drying at 120° i t beoame very powdery.The best yield with t h i s catalyst was 77.5$. One attempt to duplicate t h i s oatalyst gave a p r e c i p i t a t e l e s s o r y s t a l l i n e and much more soluble in a c i d . This i s a t t r i b u t e d to a difference in the composition of t h e sodium aluminate which i s known to vary .The p r e a i p i t a t i o n i s governed somewhat by the composition of t h e aluminate. I t oould not be washed free from a l k a l i and was considerably l e s s active .The oatalyst was however duplicated in other attempts. Oatalyst 0 : This catalyst was sensibly the same in appearanoe,properties and a c t i v i t y as oatalyst B.  500 grams  of aluminate I were dissolved in 4 l i t r e s of water and p r e o i p i t a t e d and otherwise t r e a t e d the same as B. The best y i e l d obtained was 7S$. Cat alyst D:  This i s not in the same c l a s s as the best  c a t a l y s t s but i s included here as an i n t e r e s t i n g c a s e . Tests were made with a sample of Merck's aluminum  IS hydroxide or p r e c i p i t a t e d oxide,whioh was dried for the f i r s t run at 250° and l a t e r at 400°. No other treatment was given t h i s c a t a l y s t . This c a t a l y s t . contained a small amount of free a l k a l i but gave a f a i r yield of ether .The best yield was 69 %% Catalyst E?  600.grams of aluminate I I were dissolved in  4 l i t r e s of water. The solution began to decompose at onoe p r e o i p i t a t i n g aluminum hydroxide. The p r e d i p i t a t e was washed as before but after drying was found to eon-bain a t r a c e of f r e e a l k a l i .The p r e c i p i t a t e was therefore dried at o50° and washed several times in nearly b o i l i n g water,by whioh means t h e a l k a l i was r e a d i l y removed.On drying,a t r a c e of a l k a l i was s t i l l present whioh was n e u t r a l i z e d with d i l u t e hydroc h l o r i c acid and the alumina washed u n t i l no t e s t for chloride was given in the wash water . In these washings i t was found necessary to f i l t e r as the suspension did not s e t t l e , O n drying t h i s time no t e s t for a l k a l i was obtained. The best y i e l d with t h i s o a t a l y s t was 81 ?o. Catalyst F :  The preparation of t h i s oatalyst waa similar  to that of E,  600 grama of aluminate I I were dissolved in  1.8 l i t r e s of water. The specifio gravity of the solution at 30° was 1.18, very nearly the optimum condition for the spontaneous decomposition of sodium aluminate solutions given by Russ.,  ' After washing several times the p r e c i p i -  t a t e was dried at 250° and washed again in hot water . I t was thought possible to displace the adsorbed a l k a l i by adding  20 acid.The suspension was made s l i g h t l y aoid and the alumina washed u n t i l the wash water gave no t e s t for chloride .Hot water was used. The p r e c i p i t a t e was dried again. The best y i e l d with t h i s catalyst was 80,5 /o. Note on the Washing of Aluminum Hydroxide P r e c i p i t a t e s : An i n t e r e s t i n g point was observed in connection with, the o r y s t a l l i n e p r e c i p i t a t e s such as oatalyst E and P .This has to do with the adsorption of sodium hydroxide by the p r e o i p i t a t e .The p r e c i p i t a t e was washed u n t i l the wash water gave no t e s t for a l k a l i with phenfclphthalein and onlX a very faint t e s t was observed in the presence of the p r e c i p i t a t e . On drying and moistening the p r e c i p i t a t e a s t r o n g alkaline r e a c t i o n waa given with the indicator . Successive washings with hot water now removed the a l k a l i q u i t e r a p i d l y . The alumina appeared t o hydrate again to a c e r t a i n extent and f i n a l l y »as before»no t e s t was given for a l k a l i in the wash water. On drying again more a l k a l i could be removed and t h i s time the removal was so complete t h a t no further t e s t was given with the i n d i c a t o r . With another sample»before drying*an attempt was made t o displace the a l k a l i by adding hydrochloric acid. The suspension was made s l i g h t l y acid and the p r e c i p i t a t e f i l t e r e d out and d r i e d . On drying a t e s t for a l k a l i was s t i l l given .This p r e o i p i t a t e was washed as above.It was found possible however jto completely remove the free a l k a l i from a dried p r e o i p i t a t e . The p r e c i p i t a t e was washed u n t i l t h e water gave no t e s t for  a l k a l i »and flame  31 t e s t s showed only a t r a c e of sodium in t h e p r e c i p i t a t e . On s e v e r a l oooasions o t h e r p r e o i p i t a t e s , w h i o h  after  l o n g washing » t i l l s e t t l e d rap i d l y , s u d d e n l y on one change of water f a i l e d t o s e t t l e * i n d i c a t i n g t h e a c q u i r i n g of a charge .This might be e x p l a i n e d on t h e b a s i s of t h e more complete removal of one of two adsorbed ions t h a n of t h e o t h e r .These phenomena would seem to offer an i n t e r e s t i n g f i e l d for i n v e s t i g a t i o n of ion a d s o r p t i o n both by t h e hydroxide and t h e anhydrous oxide .As t h i s was a s i d e l i n e of t h i s r e s e a r o h p r e s s u r e of time made i n v e s t i g a t i o n impossible.  CALCULATION AND ACCURACr.OF RESULTS. The r e s u l t s of t h e experiments r e p o r t e d i n t h i s p a p e r a r e c a l c u l a t e d on t h e b a s i s of t h e p e r c e n t a g e conv e r s i o n of t h e a l c o h o l i n t r o d u c e d i n t o t h e r e a c t i o n t u b e i n t o t h e produdta c o l l e c t e d . T h e d a t a given here a r e a l l f o r o a s e s where t h e dropping method of a l c o h o l f e e d WRB used. In t h e s t a n d a r d r u n s by t h i s method about 21 o c . of a l c o h o l were p a s s e d i n t o the t u b e . This was convenient and •ufficient  to permit a c c u r a t e measurements as mentioned in  c o n n e c t i o n with the method of a n a l y s i s .After  allowing  f o r a s l i g h t conversion t o e t h y l e n e of not over 5 h t h e u n c o n v e r t e d a l c o h o l » e t h e r and i t s water e q u i v a l e n t were p r e s e n t i n a t o t a l volume of about 30 oc.The method of a n a l y s i s dould be a p p l i e d d i r e c t l y .The e t h y l e n e was  33 measured at room temperature and atmospheric pressure in a c a r e f u l l y graduated aspirator .Corrections were not made to standard conditions as these were deemed n e g l i g i b l e . A check was made on a l l possible loss of alcohol or products by weighing the condenser and contents and calculat i n g the weight of ethylene.The sum of these weights checked with the weight of the aloohol used in a l l cases.Only when t h e ethylene yield was high was any appreciable quantity of ether c a r r i e d into the gas receiver and t h i s did not occur in the runs here r e p o r t e d . As a check on the conversions determined! mixtures containing e t h e r , a l c o h o l and water in the amounts caloulated for a standard ru$ were made up. The amount of ether s e p a r a t i n g out on analysis from these mixtures was the same as t h a t separating for the products of the runs .The c a l c u l a t i o n s are considered accurate to 1 j». A further indication of high y i e l d s of ether was best afforded by the fact that for t h e / c a t a l y s t s here mentioned t h e l i q u i d products separated out into two layers in the r e c e i v i n g vessel.A separation in such mixtures only occurs when the components are present in proportions co rrespondiag t o approximately BO $ conversion. Exoess water such as would correspond to ethylene formation causes a separation at s l i g h t l y lower conversions to ether .In t h i s wor.li the ethylene formed,and*consequently*the exoess water were very l i t t l e .  35 RESULTS AND DISCUSSION. DEHYDRATION OF ALCOHOL TO ETHER: These experiments have o shown t h a t 3o0 i s t h e best temperature for e t h e r f o r m a t i o n . The r e s u l t s show t h a t t h e t o t a l a l c o h o l dehydrated a p p r o a c h e s a maximum value as t h e l e n g t h of time of t h e r u n i s i n c r e a s e d . The best r a t e of flow v a r i e d with t h e different  c a t a l y s t s s l i g h t l y > r $ n g i n g from 15 to 30 oo.per  hour .At r a p i d t a t e s of flow t h e t o t a l dehydration off  falls  and at slower r a t e s t h e r e l a t i v e amounts of e t h y l e n e  formed i n c r e a s e at the expense of t h e e t h e r .This has also been shown by Pease and Yung. R e s u l t s w i t h the d i f f e r e n t  o a t a l y s t s are shown in  t a b u l a r f o m . T h e oolumn headed d r y i n g t e m p e r a t u r e  refers  t o t h e t e m p e r a t u r e t o which t h e c a t a l y s t was h e a t e d in d r y i n g . I n some oases a c a t a l y s t was used a f t e r h e a t i n g to one t e m p e r a t u r e and t h e n h e a t e d t o a higher temperature and f u r t h e r t e s t s made. Heating up t o 400  increased the  a c t i v i t y . The react a n t s and p r o d u c t s were measured by volume throughout and t h e i r weights c a l c u l a t e d . CATALYST A: Time of  Drying  Table 3 . Temp  Weight of  Vol.  $ conversion  of run.  Alo. used.  "Ether coll.  of C3H 4  350±3,  16.70  8.3  210cc  61.5  3.6  rl  16, ,55  9.55  330  70 .3  3.7  400  16 AC  9.50  750  70, .5  9*3  65  17, ,15  9.8C  590  7 1 , .0  57  1 6 . .65  9<.8-5  480  74, .8  5.9  4,9  1 6 , ,40  else  530  70, .0  8.9  .run* inrtimins. 66 135 85  Temp . 500°  to Ether  to C3H4  7.1  c  34 CATALYST B: Time of r u n :Ln mint 3 . 560  Drying Tergp . 500  Table 5 . Temp . Weight of Ether of r u n A l o . ooll. Deg.C u s e d grams 350*3 3 5 . 7 5 1 4 , 6  Vol.of C3H4 00.  i» c o n v e r s i o n to to Ether °Z^i  SOO  73.3  7.1  «  14.40  7.9  soo  69 .0  4.3  n  16.54  10.3  450  lfc.5  6.3  70  «  16.54  10,3  340  75  H  16.60  10,5  340  65 150  400  CATALYST C : Time of run in mins. 95  77.5 77 .5  5,0 3.9  Table 4 •  Drying Temp . Deg.C.  Texrp. of r u n Deg.C.  550  35013  Weight o f Ether Alo. doll. used g r ams 16.64 10,55  V o l . o f •f> c o n v e r s i o n to to Ether CgH^ 300  77.3  3.5  110  K  16,63  10.65  310  79 . 4  3.6  305  II  16.4°  10.50  540  76 .0  4.3  N  16.50  10.30  560  76 . 0  4.7  n  16.50  10,55  3 40  76 , 0  3.9  n  16.50  10.55  360  76 . 0  5.3  95  400 i  64 71 CATALYST D: "Time of Drying r u n i n Temp. Mins. Deg.C. 75  550  108  400  Tabled Weight of Vol.of Temp. A l o . Ether CgH^ of r u n used c o l l . oc. Deg.C. i n grains. 350*3 16.65 6.4 60 9.5 110 16.65  # conversion to to Ether 03%. ^ „ 47.7 0.6 1.4 69.0  35 CATALYST E:  Table 6 .  Time of Drying Temp. r u n in Temp, of run mine. Deg.C, Deg.C.  Weight of Vol. Alo. Ether O3H, used o o l l . 00 in granss  So  400  35012  % conversion to Ether C2H,.  16.5 C  10.73  &?0  60.6  4.5  65  "  16.6C  10.60  160  60.6  3.3  107  "  16.60  10,60  330  60.6.  3.7  CATALYST F r  o This c a t a l y s t was .heated a l i t t l e above 400  whioh a p p e a r s t o have d e c r e a s e d i t s a c t i v i t y a l i t t l e * a s i t was p r e p a r e d t h e same as c a t a l y s t E. The a c t i v i t y a p p e a r s t o have been reoovered with use a s i s shown in f a b l e 7 . I n d i c a t i o n s were given in t h e case of o t h e r c a t a l y s t s t h a t the a c t i v i t y i n c r e a s e d with use t o a c e r t a i n p o i n t . The e t h y l e n e 1 B h i g h e r with t h i s o a t a l y e t than with Table 7 , Time of Drying r u n in Temp. mine. Deg.C. 66  430  Temp Weight of Vol % conversion of run Alo Ether C3H4 to Deg.C. used o o l l . 00 Ether C^H^ i n grams 35013 16.55 1 0 . S5 iOO 76.0 5.0  67  "  16.55  10.4£  £00  76.5  £.7  65  "  16.50  10.7S  £40  60.5  i.3  o a t a l y s t E whioh i s a t t r i b u t e d t o t h e d r y i n g t e m p e r a t u r e being too high. EFFECI OF WE-RUNIUHG THE PRODUCTS : An attempt was made t o f i n d t h e e f f e o t of use of more o a t a l y e t but owing t o i n a b i l i t y t o c o n t r o l t h e t e m p e r a t u r e in t h e long furnace which had t o be used t h e i d e a was abandonned.As an a l t e r n a t i v e t h e e f f e o t of r e j r u n n i n g t h e p r o d u c t s was d e t e r mined. About  36 100 o o . of a l o o h o l were p a s s e d over t h e o a t a l y s t and p r o p o r t i o n a t e amounts of t h e two l a y e r s giving a t o t a l volume of 20 oo .were analyzed.The amount of e t h e r in t h e whole p r o d u c t and i n t h e balance was c a l c u l a t e d . T h e remaining p r o d u c t was t h e n p a s s e d over t h e o a t a l y s t again .The two l a y e r s ware i n t r o d u c e d i n r a t e s p r o p o r t i o n a t e t o t h e i r amounts by means of two d r o p p e r s u n i t e d i n t o a oommon d e l i v e r y t u b e . Again a sample c o n t a i n i n g t h e two l a y e r s in p r o p o r t i o n a t e amounts and having a t o t a l volume of 30 oc .was analyzed.The amount of e t h e r in t h e whole p r o d u c t was c a l c u l a t e d and was found t o be s l i g h t l y lower t h a n b e f o r e . T h i s d e c r e a s e was due t o t h e formation of a l i t t l e e t h y l e n e and corresponded t o t h e e q u i v a l e n t of t h e e t h y l e n e o l o s e l y . T h e p r o d u o t s were etentained i n two b u r e t t e s > g r a d u a t e d from t h e bottom u p , between t h e runs .This enabled e q u i v a l e n t amounts t o be taken out when d e s i r e d . EFFECT OF TEMPERATURE ON THE REACTION: The t e m p e r a t u r e  effect  i s shown by Table & .The runs were made with c a t a l y s t C. Table 6 . Vol. Weight of Ether CgH^ Alo. c o l l e c t e d cc used i n gr am s  ft c o n v e r s i o n to Ether C3H  Deg.C.  Time of r u n in mini.  33513  148  16.5C  9.13  50  69.0  0.6  340t3  93  16.55  10.00  130  75.0  1.5  35013  64  16.50  10.55  340  76.0  3.9  365*3  66  17 .OC  Q.8%  600  75.0  7.5  Temp. of r u n  37 EFFECT OF TRACES OF ALKALI ON THE CATALYTIC ACTIVITY: The effeot  of t r a c e s of i m p u r i t i e s such aa 30dium  hydroxide*and no doubt t h a t of s a l t s ae w e l l * i s shown by t h e d a t a in Table 8 . A o a t a l y s t was p r e p a r e d by t h e spontaneous decomposition of sodium aluminate and should have been in a l l r e s p e c t s t h e same as c a t a l y s t E. On d r y i n g i t was founA t h a t t r a o e s of f r e e a l k a l i s t i l l remained in t h e p r e c i p i t a t e . The o a t a l y s t was t r i e d out in t h e fumaoe and a very poor y i e l d r e s u l t e d . The o a t a l y s t was t h e n f u r t h e r washad and a muoh g r e a t e r a c t i v i t y r e s u l t e d . While t h e a c t i v i t y was not as great as for t h e best o a t a l y s t i t i e q u i t e p r o b a b l e t h a t s i n c e the o a t a l y s t was used before rewashing the i i p u r i t i e s were not l a t e r a l l removed.The e f f e o t of b e t t e r washing is> however, shown i n no unmistakable manner. Table 8 . Time of Drying Temp. run in Temp, of r u n . mine Peg.C. Deg.C.  Weight of Alo. Ether used coll.  Vol. C-H. 3 otf  # conversion to Ether C2H4  Before r e w a s h i n g : 75  400  330i2  16,60  5.83  60  U>.0  O.fc  17.10  S.fcO  1r30  71.0  5.0  After rewashing: 6£  "  *  DURATION OF CATALYST LIFE:  That t h e o a t a l y a t s w i l l remain  a c t i v e for a c o n s i d e r a b l e l e n g t h of time i s shown by Table 10 f o r a run with o a t a l y s t C a f t e r more than 1000 0 0 . of had been p a s s e d over i t . The a c t i v i t y shows no sign of impairment.  alcohd  28 Table 10 Temp. Time of run o f i r u n  Weight of Ale Ether 7  250^2  $&  16.55  Vol of C9H.  jar convexsion t© Ether fcCalU  it. e. .  10,56  500  78.4  5.7  In some o a s e s t h e a l c o h o l t e n d e d t o deposit  car_  bonaoeous m a t t e r on t h e c a t a l y s t which was evidenced by a b l a c k e n i n g of t h e l a t t e r but i n t h e case of t h e b e s t c a t a l y s t s t h i s d i d not appear t o happen .While t h i s may be due t o i m p u r i t i e s i n t h e a l o o h o l i n some of t h e oases>for t h e nicest p a r t i t i s c o n s i d e r e d t o have been due t o t h e n a t u r e of t h e s i d e r e a c t i o n s t a k i n g p l a o e with t h e c a t a l y s t i n quest ion .When carbon was d e p o s i t e d on a c a t a l y s t t h e n a t u r e of t h e r e a c t i o n appeared t o be modified somewhat as more e t h y l e n e was o b t a i n e d , FORMATION OP ALCOHOL PROM ETHER AND WATER: N  The r e v e r s i b i l i t y of t h e r e a c t i o n was p r e v i o u s l y ?  shown by Ipatiew  5 ti'  and l a t e r by Pease and Yung .  Some r u n s  were made in which e t h e r and water in equal molecular amounts were p a s s e d over c a t a l y s t C.The amount of e t h e r and water used i n t h e r u n s were e q u i v a l e n t t o a l i t t l e o v e r 2$ oc.of alcohol*. The p r o d u c t s were analyzed and t h e amount of e t h e r was found t o have been deoreased by an amount c o n s i d e r a b l y g r e a t e r t h a n t h e e q u i v a l e n t of t h e e t h y l e n e formed .The l a t t e r was t h e same as would have been formed if a s t a n d a r d run with a l c o h o l had been made. The d e c r e a s e in t h e amount of e t h e r was undoubtedly due t o t h e formation of a l c o h o l a c c o r d i n g t h e equation  /  29 C3H5OC3H5 •+ H20 —> 2 CaH50H.The r e s u l t s of t h e s e e x p e r i m e n t s a r e shown in Table 1 1 . The column headed p e r c e n t Table 1 1 . Temp. of run Deg.C, 350t2 •  Time Weights used Alcohol .of run Ether Water Equivalent mins. grains grams 63 1£.$C 3.50 16.65 56  lb.60  S.40  16.90  Weight Vol. EtherC3H4 Beco^pred co 1 1 . Vi 300  Alcohol formed *• c t gms fo ~ J/f 3.05 1 3 . 3 ff-f  11.95  1.64,  150  11.0  a l c o h o l formed i s based on t h e t o t a l a l c o h o l e q u i v a l e n t of t h e m i x t u r e s p a s s e d over t h e furnace .'•The iodoform t e s t was made t o determine t h e p r e s e n c e of a l c o h o l in t h e p r o d u c t s and a d e c i d e d r e a c t i o n was g i v e n . I t i s seen t h a t a p p r o a o h i n g from t h e e t h e r s i d e about 12 ft of t h e a l c o h o l e q u i v a l e n t of/xhe mixture i s o b t a i n e d as a l c o h o l * t h e time of t h e run b e i n g about t h a t of a s t a n d a r d run with a l c o h o l . The a p p a r a t u s used t o i n t r o d u c e e t h e r tod water i n t o the c a t a l y s t tube &t r a t e s of flow p r o p o r t i o n a l t o t h e i r e q u i v a l e n t s was t h e double dropper mentioned i n c o n n e c t i o n w i t h r e - r u n n i n g t h e p r d d u o t s (page 25) .The two were j o i n e d with a common d e l i v e r y t u b e and meroury dropped i n t o each i n d e p e n d e n t l y . From t h e above i t i s seen t h a t fafom t h e e t h e r  sidej  t h e e t h e r r e c o v e r e d i s e q u i v a l e n t t o n e a r l y an &&$ conversion t o e t h e r .From t h e a l o o h o l s i d e y i e l d s of abtiut 81 $ have been o b t a i n e d . T h e formation of e t h y l e n e c o m p l i c a t e s t h e c a s e somewhat but f o r t h e purpose of an approximate c a l c u l a t i o n may be n e g l e c t e d . T h u s from t h e s e v a l u e s t h e y i e l d c o r r e s p o n d i n g t o t h e e q u i l i b r i u m may be e s t i m a t e d t o bf 8 5 $ .  hi  Thia would mean a mixture c o n t a i n i n g 13 .5 mol p e r c e n t of each e t h e r and water and 15 mol p e r c e n t of aloohol.The e q u i l i b r i u m 425 y 425 c o n a t a n t o a l o u l a t e d from t h e s e v a l u e s i s given by K'l *a .< « (.15)3 - 6.0 . HEAT OP REACTION AKD THERMAL DATA: The t h e r m a l d a t a given are most 14 t h e / r e l i a b l e values obtainable  and are as quoted by Pease  and Yung .The h e a t s of v a p o r i z a t i o n are f o r 30°c and have been o b t a i n e d by Pease and Yung by p l o t t i n g v a l u e s for  different  t e m p e r a t u r e s and i n t e r p o l a t i n g for 30 . 3  4 00 3 * 6 H3fy—* 3 C2H50Ha)> 6O3 ° 3 H 5 0 % ^ 3 °3H50fW  -655600 OStlvRi .Em .Ben .) - 3 0 6 0 ° ('V"?  3 .C3H50H^ - * (C 2 H 5 ) a 0 ^ + H30<v)  +Q  **%,)-*%%  -10450/—'  (C2H { .) 3 O #> -*(O 3 H 5 ) 3 O 0)  -6500  6  +653,500 fs**»—^>  0 3 + CQaR5)2C|y—>4 00 3 *-5 HgOjj  Hence  Q*  (**.)  655800 -f 3 0 6 0 0 - 10450 - 6500 - 6 5 3 5 0 0 «  7100 S a l ,  Adopting L*wis' n o t a t i o n AH *-Qp* -7100 C a l . Prom t h e heat of t h e r e a c t i o n and t h e above value of t h e e q u i l i b r i u m c o n s t a n t the s t a n d a r d f r e e e n e r g y of t h e r e a c t i o n may be c a l c u l a t e d . AP» -RT In K where I n s t a n d s f o r t h e l o g a r i t h m t o t h e base e»or A P * -2.505 RT log^cK. AP cornea o u t t o be  - 1560.The s t a n d a r d f r e e energy change v a r i e s with  t h e t e m p e r a t u r e aooording t o the e q u a t i o n AP - AH -r IT . Prom t h i s t h e i n t e g r a t i o n c o n s t a n t I may be c a l c u l a t e d and comes o u t to be 4 . 6 6 . C o n s i d e r i n g AH to be constant over  this  t e m p e r a t u r e range t h e e q u i l i b r i u m constant at 375° may be c a l c u l a t e d , A P - . - = - 7 1 0 0 +• 5 4 6 " 4.66 s - 4 4 4 0 .Prom t h i s 946  14 L a n d o I t - B o r n s t e i n , " T a b e l i e n " , J .Springer , B e r l i n  1^35  51 log K =  .1 ,whence K-.? 5 .68 .This corresponds 1.966 x 548 K3.SOS _o *'  t o a maximum.possible conversion at 37 o  of 82.8$ which i s  much h i g h e r t h a n t h e value given by Pease and Yung. I t c e r t a i n t h a t t h e e q u i l i b r i u m at 375  is  i s not where Pease and  Yung have p l a c e d i t , C a l c u l a t i o n s of t h e s t a n d a r d f r e e energy of e t h e r a r e s c a r c e l y j u s t i f i e d on t h e d a t a a v a i l a b l e . In a d d i t i o n t o t h e p o s s i b l e r e a c t i o n s a l r e a d y mentioned* another r e a c t i o n (C2H_)3 0—"G^H.  -t C3H5OH  i s a l s o p o s s i b l e . Since t h e method  of a n a l y s i s d e t e r m i n e s one p r o d u c t only and t h e o t h e r s may vary i n s e v e r a l ways,a d e t e r m i n a t i o n of t h e exact e q u i l i b r i u m p o i n t is hardly p o s s i b l e . DISCUSSION OF THE VARIOUS CATALYSTS FOR ETHER FORMATION. With alumina p r e p a r e d by d e h y d r a t i o n of t h e p r e c i p i t a t e from aluminum s a l t s with ammonia only low y i e l d s have been r e p o r t e d b y ' t h o s e who ha^e used t h i s c a t a l y s t * This p r e c i p i t a t e i s very s o l u b l e i n a c i d s and a l k a l i e s . With t h e h y d r o x i d e p r e p a r e d from s o l u t i o n s of sodium aluminate with s u l p h u r i c a c i d a y i e l d of 7 4 fa has been o b t a i n e d i n t h i s i n v e s t i g a t i o n . This p r e o i p i t a t e i s c o n s i d e r e d t o b e ' crystalline  but i t i s r e a d i l y s o l u b l e in a c i d s .  p r e o i p i t a t e produced by COg from a ofo o r s t r o n g e r  The solution  of sodium aluminate i s d e c i d e d l y c r y s t a l l i n e and very i n s o l u b l e i n a c i d s and a l k a l i e s . T h i s p r e c i p i t a t e gave a c a t a l y s t y i e l d i n g 76 -79$ e t h e r .The p r e c i p i t a t e o b t a i n e d by  . 52 the spontaneous decomposition of sodium aluminate gave the most d i f f i c u l t l y soluble p r e c i p i t a t e of a l l and was the best catalyst giving a y i e l d of 80-81$ e t h e r . The d i s t i n c t i o n between c o l l o i d a l aluminum hydroxide and the t r u e c r y s t a l l i n e aluminum hydroxide obtained by p r e c i p i t a t i o n from solutions of sodium aluminate was made 7 15 by van Bremmelen and substantiated by Martin.MiHigan Tias shown t h a t the compound Al(OH) -C loses most of i t s water on h e a t i n g to 300 c and after being heated above 275° and then allowed t o rehydrate, the water i s adsorbed and not ohemioally oombined in the t r u e sense .The hydroxide i t s e l f  furnishes  a d i s t i n c t c r y s t a l l i n e X-ray p a t t e r n but on heating above S25° gives another p a t t e r n which i s that of a c r y s t a l l i n e s t a t e according to Mead as quoted by Milligan^but  different  from the f i r s t , I t would be i n t e r e s t i n g to observe whether t h e different p r e c i p i t a t e s from solutions of sodium aluminate whjboh have been used as c a t a l y s t s in t h i s work have different p a t t e r n s . The marked difference in t h e i r s o l u b i l i t y in aoids indicates a difference in their structure .Until the exact nature of each p r e c i p i t a t e i s determined i t i s not possible t o develope a d e f i n i t e theory of the mechanism of the react i n n . SUMMARY.  1.  A study of the c a t a l y t i c dehydration of ethyl alcohol  t o ether has been made in the gaseous phase in t h e presence of alumina at 350 . 3.  The maximum amount of ether was obtained with the  15 Milligan, J.PhyB.Chem,,36,3« (1933)  product obtained by dehydration of the o r y s t a l l i n e aluminum hydroxide r e s u l t i n g from the spontaneous decomposition of s o l u t i o n s of sodium aluminate .The highest yields were ototained at 350  and amonnted to QOJ>ii j> of the t h e o r e t i c a l  conversion to e t h e r . S.  Aloohol was obtained from equimoleoular q u a n t i t i e s of  e t h e r and water»showing the reaction to be reversible .The p o s i t i o n of equilibrium has been determined at 350  to  correspond to a maximum possible conversion to ether of about &5 ^.The corresponding equilibrium constant i s 8.0 . i.  I t has been shown that absolute p u r i t y of the catalyst  i s e s s e n t i a l . Impurities may be more quiokly tnd completely removed by drying the p r e c i p i t a t e and washing again.5.  Heating the c a t a l y s t to about 400° lout not higherjin  drying»gives the most active product. 6.  The c a t a l y s t s p r e p a r e d as d e s o r i b e d r e t a i n t h e i r  a c t i v i t y , u n i m p a i r e d , a f t e r long u s e . CONCLUSION . The c a t a l y t i c p r e p a r a t i o n of e t h e r by means of aluminum oxide by the method developed in t h i s  investigation  h a s e x c e p t i o n a l commercial advantages .The p o s s i b l e u s e s for e t h e r a^e i n c r e a s i n g rap i d l y , n o t only as a solvent but a l s o i n m i x t u r e s as a motot f u e l » p a r t i c u l a r l y i n oold r e g i o n s . A very v a l u a b l e a p p l i c a t i o n of t h i s use of e t h e r w i l l be to make p o s s i b l e the use of aloohol as a f u e l . The p r e s e n t method of manufacture,by d e h y d r a t i n g a l o o h o l with s u l p h u r i c a o i d i s not o n l y c o s t l y but troublesome.  £4 The l o s s of alcohol i s considerable,usually about SO/o and t h e a c t i v i t y of the sulphuric acid quickly diminishes. In the method above described the c a t a l y s t i s e a s i l y prepared and can be exactly duplicated and gives yields higher than are commercially f e a s i b l e by the sulphuric aoid method. In view of the large soale upon which t h i s investigation was c a r r i e d out,approaching semi-commercial s i z e , i t i s aafe to consider the high yields obtained can be duplicated commerc i a l l y .The c a t a l y s t s have been shown to r e t a i n t h e i r high a c t i v i t y with long u s e . The mechanical side of the operation i s extremely simple and could be c a r r i e d out with l i t t l e cost.  0O0  I wish to take t h i s opportunity of expressing my h e a r t i e s t appreciation to Dr.R.H.Clark,Professor of Organic Chemistry>for h i s kind advice and assistance in connection with the work. 0O0 .  S£  BIBLIOGRAPHY. Homer A d k i n s j A c t i o n of Alumina, T i t a n i a and T h o r i a on E t h y l and I s o p r o p y l A c e t a t e s * J o u r n a l Amer .Chem.Soo . , 4 4 , 5 6 5 ^ 1 9 3 2 ) The S e l e c t i v e A c t i v a t i o n of Alumina f o r D e c a r b o x y l a t i o n and f o r D e h y d r a t i o n , J.Amer .Chem .Soc . * 4 4 , 2 1 7 5 (1932) R e a c t i o n s of F o r m i c Acid a t t h e S u r f a c e of S e l e c t i v e A c t i v a t i o n of  Alumina  Alumina,J.Amer.Chem.Soo.,  45.S09 (1925) . The C a u s a t i o n of O r g a n i c R e a c t i o n s by Alumina and T h e o r i e s o f C a t a l y s i s , J.Amer . C h e m . S o c , 4 6 , 1 5 0 ( 1 9 3 4 ) . W.D.Bancroft;Contract 21,575  C a t a l y s i s I , J o u r n a l of P h y s i c a l  Chemistry  (1917)»Ithaca,N.Y.  J .-van Bremmelen, ( On C o l l o i d a l and C r y s t a l l i n e  Aluminum  H y d r o x i d e s ) R e o e u i l d e a Travaux Chimiques d e s P a y s - B a s » 7 , 7 5 (1666) L e i d e n , H o l l a n d ( t h r o u g h M i l l i g a n , s e e  belowl.  A . D i t t e t D e c o m p o s i t i o n d e s A l u m i n a t e s A l k a l i n s en P r e s e n c e de 1* Alumine»Comptes Rendus hebdomadair-es d e s  S^eances  de U A c a d e m i e S c i e n c e s , 1 1 6 , 1 8 5 (1S&5) P a r i s . Graham Edgar and W.H.Schuyler j E s t e d r i f i c a t i o n E q u i l i b r i a , ±n t h e fijaseous P h a s e , J o u r , Amer . C h e m . S o o . , 1 6 , 6 4 ( 1 9 2 4 ) . " J . E n g e l d e r : S t u d i e s in Contact C a t a l y s i s , J o u r . P h y s i c a l C h e m . , 2 1 , 6 7 6 (1917) W l . l p a t i e w K a t a l y t t i s c h e R e a c t i c n e n b e i hohen Temper a t u r e n und D r u c k e n , B e r i o t e der d e u t s c h e n chemischen 57,3966(1904),Leipzig.  Gessellsohaft,  S6  .  I .Langmuir{Chemical R e a c t i o n s on S u r f a o e s » T r a n s a c t i o n s of t h e Faraday Society,17,617(1922) through Chem.Abstracts (Aii:er.Chem.Soc) 16,7 (1923) E.Martin {Alumina and Aluminates,Moniteur Soient if iojie,(5) 5 , 2 3 5 ( 1 9 1 5 ) P a r i s , t h r o u g h Chem.Abst,(ACS> 10,571 (1916) L . M i l l i g a n t T h e Mechanism of Dehydration of  Crystalline  Aluminum Hydrate,and of the Adsorption of Water by t h e R e s u l t i n g Alumina,Jour.Phys.Chem.,26,21:7 (1923) Ithaca>NY R .N .Pease and Chi Chao Yung: The C a t a l y t i c Dehydration of Ethyl Alcohol and Ether by Almmina, J .Amer .Chen; S o c . , 46,590 (192 4 ) . The P o s i t i o n of Equilibrium in t h e Alcohol-Ether Reaction a t I'oCP and a t 275^ J .Amer. Chem. Soc . , 16,3597(1934) F . R u s s : Uber Tonerdehydrat , Z e i t s o h r i f t fur anorganisohe und allgemeine Chemie* 41,216 (19C4) , L e i p z i g . A.Sanfourohe and A.M .Boutin : D e n s i t i e s and R e f r a c t i v e  Indices  of Mixtures of Water Alcohol and E t h e r , B u l l e t i n de l a Societe* Chiiuique de Pranoe(4)-51,456(1923iParis,through Amer.Chem.Soc .Abst r.»17»65b(1935) and Pease and Yung above J.B.SenderenstDe'shydratation C a t a l y t i q u e s des Aloools p a r Voie Seche»Annales de Chimie et de P h y s i q u e , ( b )  35.505  (1913) , P a r i s . Miss A.G-.Winter: A Qualitative Determination of Ether in Mixtures of E t h e r , Alcohol and Water .Thesis submitted for Bachelors DegresUniversity ©f B r i t i s h Columbia A p r i l 1935. A.Mailhe and F .de Godon: P r e p a r a t i o n C a t a l y t i q u e p a r ¥oie Seche de 1 ' E t h e r O r d i n a i r e , B u l l e t i n de l a S o c i e t e ' Chimique de F r a n c e , . 3 5 , (1916) 5 6 5 , P a r i s .  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0061834/manifest

Comment

Related Items