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The investigation of a gas evolved from quatz at high temperature Carpenter, Gilbert Brown 1926

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THE INVESTIGATION OF A GAS EVOLVED FROM QUARTZ AT HIGH TEMPERATURES. BY GILBERT BROWN CARPENTER  U.B.C LIBRARY CAT. NO. LEsfo-nxfc-  Czls  ACC. NO. STy-S^f  .  THE INVESTI SATIOH OP A OAS EVOLVED FROM QUARTZ AT HIOH TEMPERATURES. by GILBERT BROWN CARPEHTER.  A Thesis submitted for the Degree of Master of Arts • in the Department of Chemistry.  The University of British Columbia, April 1926.  OJ^kAAru-<-JL <  EvH< CW-I^JiroJUi  TABLE OP CONTENTS. I.  Introduction.  a. b. II.  in.  Measurement of rates. a. Apparatus, Plate I. b. Procedure. o. Results, Plates II, III, IV, V.  Analysis of gas. a. b* o. d.  IV. V. VI.  Historical Object of research.  introduction, Apparatus, Plate VI. Procedure. Results  Discussion of results. Summary. Bibliography.  THE IHVBSTIGATIOM OF A SAS EVOLVED FROM QUARTZ AT HISH TEMPERATURES, During the oause of investigations involving the use of an evacuated quartz bulb heated to about 1000° 0 it was found that a slow leakage of gas appeared to take place into the bulb*  No leakage took place with the bulb  oold hence the gas must come from the heated quartz. It appeared that this effect might possibly be due to actual diffusion of gas through the quarts at the elevated temperature and J. A. Harris*1' followed up this suggestion, presenting his work for his Master's Thesis in 1923 at this University.  It was found, in the present research,  that the enclosing of the bulb within an evacuated bulb Of the same material caused no appreciable decrease in the amount of gas given off.  No reference in the liter-  ature can be found to a gas emanating from quartz at any temperature for any length of time but it is possible that certain effects hitherto attributed to diffusion have been compounded with the phenomenon observed here. Sheppard (si -' shows that a gas is given off from quartz vessels when they are initially heated to a temperature of 1000° C.  The gases found in his quartz were carbon  dioxide, carbon monoxide, nitrogen and water.  Judging  from his remarks this gas oould be removed in a reasonably short period of time and since he used a quarts  - 2 tube constructed from translucent quartz which would Include a considerable amount of gas, his results do not seem trustworthy. The present research was undertaken to fully investigate the manner in which the gas was evolved and to determine its constitution.  Measurement of Rates* The apparatus used is illustrated in Plate I* The bulb A is of transparent quartz around which is a jacket of the same material which could he evacuated. The pressure in the outer bulb could always he read en the mercury manometer Q«  Both these quartz tubes  were joined to the rest of the apparatus by Zhatinsky seals{  Sj, Sg on the diagram.  The upper seal was  protected from radiation of the furnace by a sheet of  asbestos X« The pressure in the apparatus was measured by a  Mcleod gauge D.  This gauge is graduated so that pressure  ratios of 10" 4 , 10" 8 and 2xl0"3 could be read off as desired* The quartz bulbs were contained in a platinum wound furnace B. Platinum winding is neoessary for this investigation, as the furnace is kept at a temperature near 1000° C for a considerable period of time.  - 3 The outer and inner bulbs could be evacuated by opening the mercury sealed stopcocks J and K and pumping off through the tube P by two mercury condensation pumps in series, operated by an oil pump. These pumps were built in accordance (3 J  with the design  of C. Kraus. The temperature of the furnace was regulated by an alternating current volt meter oonneoted across the binding posts of the furnaoe.  The furnace gave a  temperature of 950° C with a voltage of 80 volts across the terminals*  During all rate readings this was kept  constant but since the city current varies a good deal and the furnace was run continuously it was impossible to keep constantly at this temperature at all times. The average temperature, however, would be at about this value* The apparatus was evacuated at a somewhat higher temperature for about a week before the first rate measurements were taken.  Unfortunately, due to the  furnaoe burning out and other accidents, air had to be let in three times during the four months that the gas was observed to be ooming off and henoe an accurate check of the time the bulb was heated is not available. After each oooasion, however, the bulb was heated and evacuated for several days before the gas was again  • 4 allowed to collect. When a good vacuum had been attained and a constant temperature reached the stopcocks J and K were olosed at zerot time and readings taken on the Mcleod gauge D at regular intervals.  The temperature of the  furnace as stated above was kept constant by careful regulation. The apparatus was first tested for a leak in the system by evaouating it and letting it stand cold for six days. No increase in pressure was observed in the MoLeod gauge.  This procedure was carried out again at  a later stage of the work, since it is well known that stopcocks and Khetinsky seals may slowly develop leaks, but no pressure increase was observed. The pressure was plotted against time as shown in the accompanying graphs.  January rate determinationst TABLE I. Time (min.5 0 7 17 24 30  Press.x 10" cm. .75 2.63 5*01 6.45 9.99  p  1.86 2.38 1.44 3.54  ^  .269 .238 .206 .584  Ay. rate of pressure increase 2.324 x 10""* cm. per min.  P/-<?SSi*T  X  /0~Tcms<  - 5 -  Time (min.) 0 10 15 25  Press.xl0"*4om. 1.91 4.90 5.65 7.42  p  3.00 .95 1.57  ^  .30 .19 .157  Av. rate of pressure increase s .246 x 10** cm. per min.  TABLE III. Time (min.) 0 "1 5 15 21  Press.xlQ-4om. 1.65 2.42 3.00 5.24 6.52  p  .77 ,58 2.24 1 .28  ff at .39 .19 .224 .213  A T . rate _ef pressure increase a ,254 x 1 0 " 4 cm. per min,  TABLE IV. Time (min.J 0 5 26 35  Press,xi0" 4 om, .9 2.01 5.51 6.56  p  1.11 3.50 1.09  &&  »Z2 .104 .16  Ay, r a t e e-f p r e s s u r e i n c r e a s e s .161 x 10~ 4 cm. p e r min.  A*v# r a t e of i n c r e a s e f o r January a ,239 x 10  cm, p e r min.  February r a t e  determinations!  TABLE V . Time  (mini  0 .  5 12 24 38 57  Press.z 10  -4  cm  .35 .82  .47 .68 .81 .74  1.50 2.31 3.05 4.60  djt dt  P  1.55  .094 .095 .068 .053 .080  A T . r a t e of -pressure i n o r e a s e « . 0 7 8 x 1 0 ~ 4 am. p e r mln,  TABLE V I . lime  (hrs.3  0 16^  P r e s s , x 10  cm.  8.9 70.0  p  61.1  ^? at .060  Hate o f p r e s s u r e i n o r e a s e = . 0 6 0 * 10""4 am. p e r min.  TABLE V I I . Time ( h r s . ) 0 46  P r e s s , x 1 0 ~ 4 cm. 1.37 112.8  p  99.1  -g&  .036  Hate of pressure increase s .036 x 10""4 om. per mln. 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M i :  |' : - - ' ; : ± H ; [T :  -MMX  ;  ;  : ; i  " X  . u,, :  :  Os,  ; l,i ;! -j-• - r - r - , - - r •  j  :_u 'TM1M "i _, !"iT  ^z^zdftLzz. i } — - -;-H-r :r-:rr .._;4__ - r - : _ r"1 j _ _ i . j _ C MM. -H-f-----  •_X-UM :  o  .,.,  i i  -;-;—|—|—  Md±  - H f r i M ± r xxJx X x i t i , : -!-:—,-  3  ^^  ^TS  ._v_;M_,..  -f-r-4-  :,M  : J 7  :  ...M - -  •i-j-ri: .J.-I..J.J..  I+XIJJ X X _.._LLJ_ _  j  ;  \  :'  Si±  ;  j  "'rrr'r 1 ! 1 1  . . _ „ _ . . _  .....  . !  i  .1  ...J . u . .  \,  J i i" ;" i ""1 — J - Ui T. X I X _ L ,  ^ \  ::: M.:J::  %, • H - - A:  ..... ...... i .. j .._._U J  M M  ••-•;'": - ; - | - , : r ; : T /  C^  /Pz-e-ssarex/o  ^csr?? a n '-LHSitJM » NO'saiAra ' H i m s ^uadVd Hdvao v£ o  - 7 -  TABLE VIII. Time (min) 0 5 15 SO 50 70 90 110 ISO  Press* x 10" 4 cm. 1.90 2.13 3.20 4.45 5.60 6.64 7.32 8.09 9.00  p  .14 1.07 1.25 1.15 1.04 .68 .67 .91  .028 .107 .083 .057 .052 .034 .034 .045  Ay. rate of pressure increase - .055 cm. per min.  TABLE IX. Time (hrs.) 0 42.fi 47.5 54.5 66.5 71.5 76.6 92*5 98.5  Press, x 10 1.90 56.0 63.5 72.8 106.3 110.6 118.0 130.0 138.8  cm.  P  54.1 7.5 9.3 33.5 4.5 7.2 12.0 8.8  dt  .022 .025 • 022 .046 .015 .017 .014 • 013  Av. rate of pressure increase » .022 cm. per min. She temperature of the room was not regulated for the long intervals and as stated above the furnace temperature varied.  This may account in some degree for the varying  results. It would seem that the gas comes off a variable rates but the general average tends to become fairly constant.  - 8 She rate falls off for the first hour but then tends to become fairly constant.  The average rate falls off  slowly with time but although pressures far beyond the MoLeod gauge were reached no equilibrium pressure was observed*  Aajsjali nfcfeifaut* The analysis of very small quantities of gas although a very important subject does not seem to have been investigated very fully*  The method out  lined here although developed with referenoe to the subject under investigation seems capable of under development*  The total amount of gas collected in  a reasonable time is comparatively small* consequently the gas must be analysed at this pressure and not taken out and analysed in the usual way*  A somewhat similar  devloe was used by A* Guye and ¥• Hermann*  Their pro-  cedure was only applied to air and seems more open to error*  They do not mention any difficulty with their  oxygen absorption apparatus as was encountered in this research* The final form of the apparatus is shown in Plate 71* It consists really of a modified MoLeod gauge with several absorption tips at 7 to oarry out tests for the various gases whioh might be present*  The ratio of the pressure  - 9 drops when a gas was absorbed to the o r i g i n a l p r e s s u r e gave t h e percentage of t h i s  gas  constituent.  The a b s o r p t i o n apparatus i s made of pyrex g l a s s c a p i l l a r y tubing w i t h three quarts t i p s s e a l e d on w i t h Khfctinsky cement.  The  volume  of t h e s e bulbs was made  very small i n comparison with the bulb E of the Mcleod gauge  Q the bulb  Tg a s p i r a l of f i n e copper wire p r e -  v i o u s l y c l e a n e d was i n s e r t e d and i n the bulb T a small 3 amount of chemically pure solid potassium hydroxide was put*  The quartz tip Tj. was left empty and used to heat  the gas alone or mixed with oxygen.  Oxygen was pre-  pared by heating chemically pure potassium chlorate in the bulb 0 and storing it in the bulb L. few samples of oxygen were pumped off.  The first  The tube and  stopcock H connected the apparatus to the asuroe of gas, w&ile the tube and stopoook 1 led to the evacuating system#described previously.  A trap T in the mercury  system prevented air entering from the mercury. In earlier work the absorption apparatus consisted of one quartz tip sealed to a capillary tube and stopcock at the same position as Z, in the diagram shown. A fine spiral of copper wire  was Inserted in the tip  and a few pieces of solid potassium hydroxide were placed In the capillary tube*  Using such an apparatus  no distinction between the separate action of the gas  - 10 with the hot copper and potassium hydroxide oonld he made hut the centred action was measured. Later the bulb T  was temporarily replaoed by a  fine oapillary of quartz whioh oonld be immersed in liquid air* The  The apparatus was otherwise the same.  apparatus was first thoroughly tested for any  possible leaks*  When a constant vacuum was maintained  for some hours the analyses were prooeeded with* The apparatus was used as an ordinary HoLeod gauge when the stopcock Z  is closed*  The  mercury level was  always brought to a fixed point in the oapillary M and the pressure read on the tube &. The gas to be analysed was let in this ugh the stopcock H.  The stopcock Z  on the scales behind 0*  was closed and the pressure read The mercury level was now  brought down slightly and the stopoooks 2. and *?8 opened allowing the gas to enter the tip with the potassium hydroxide*  It was found that cold potassium hydroxide  absorbed the carbon dioxide only at a very slow rate* Hence the potassium hydroxide was warmed to incipient fusion whioh was found to cause immediate absorption of the carbon dioxide*  This observation is in accord with  that of Lind and Bardwell*5' in a similar use of solid potassium hydroxide*  11 After a constant pressure had been reaohed the mercury l e r e l was brought down u n t i l I t j u s t shut o f f the bulb 1 from the tube attached to G*  The stopoooks  £3 and Z± were now o l o s e d and the mercury l e r e l  raised  as before and the l e r e l noted on d. A s i m i l a r performance was now c a r r i e d out with the oepper t i p .  The oopper was heated by a f i n e gas  flame to a red heat while the gas was kept at as high a pressure as p o s s i b l e on I t . t i n e s u n t i l no decrease i n  This was repeated s e r e r a l  volume  was n o t e d .  After  t h e pressure decrease was read the gas was again t r e a t e d w i t h potassium hydroxide as above. When oxygen waa mixed w i t h the gas i t was l e t  in  from the storage bulb L to a known pressure of gas and then the combined preseure read*  The mixed gases were  now heated in the t i p Tj and t h e pressure afterwards read, as i n the former e a s e s *  The gas was then t r e a t e d  w i t h the potassium hydroxide and l a t e r with hot oopper and the r a r i o u s absorptions noted* In the e a r l i e r experiments the gas was t r e a t e d • w i t h IOI cold and then w i t h hot oepper in the presence of the potassium hydroxide*  The corresponding deoreases  were noted* The absorption of the oxygen by the hot oopper was t e s t e d from time to time*  This served the double  purpoee of eheoklng up en the oopper s p i r a l and a l s o  12 the purity of the oxygen generated* Considerable difficulty was experienced with the absorption of oxygen by the hot copper at first. The copper seemed to give off gas when heated to red heat. The amount gradually diminished but it took considerable heating to reduce the rate at which it was given off. At one time the copper tip was heated to red heat for fifteen hours and gas was still given off at a very small rate*  This was afterwards allowed for.  The gas  given off was not absorbed in potassium hydroxide. No equilibrium pressure was reached although a head of 5 ems* of mercury was reached in two hours.  The only  explanation feasible is that the dissolved nitrogen in the copper is slowly driven off. The following table of data represents the results obtained with the combination potassium hydroxide and copper absorption tip previously described. % removed by potassium hydroxide ^ ^ —  "P ! • • • • — i — — — — p m f m / H t j t — — — H ^ m m m m ^ f m t m m ^ m m  1. 2. 3. 4. 5. 6.  2.0 2.25 1.60 0.00 0.00  % removed by copper and potassium hydroxide • • • n m » ^ —  ••-  n • i^  94.0 94.5 94.6 95.0 96.0 96.5  i  i. i i • • — — •  % residue i  ••  I  • •• •  i  4.0 3.2 2.6 5.0 4.0 1.5  mi  i-.-r  - 1 5 Zn the l a s t ease quoted the absorption with potassium hydroxide alone was not measured.  During  these experiments the potassium hydroxide was not heated and t h i s may aooount for the varying r e s u l t s . The oopper was removed from the t i p and the gas mixed w i t h oxygen and h e a t e d . Pressure of gas from furnace Pressure of gas a f t e r potassium hydroxide Pressure of gas and oxygen mixture Pressure of mixture a f t e r h e a t i n g in presenoe of potassium hydroxide Pressure a f t e r more oxygen added •Pressure a f t e r h e a t i n g again i n presenoe of potassium hydroxide Pressure of gas was 103.7 Total pressure deorease was 167.0  9 s •  105.7 100.0 255.6  s  -  94.5 261.5  s  265.0  This represents a deorease of about one and one h a l f volumes  of the furnaoe g a s .  Theee r e s u l t s were  afterwards oheoked in a s l i g h t l y d i f f e r e n t manner as follows. 1*  2.  Pressure of gas from furnaoe " •» « a n a oxygen mixture " , a f t e r h e a t i n g alone " of t r e a t i n g w i t h potassium hydroxide " deorease due to h e a t i n g alone " " due to potassium hydroxide Total pressure deorease Pressure of gas from furnaoe M " " and oxygen mixture " a f t e r h e a t i n g alone M <* t r e a t i n g with hot potassium hydroxide  3 =  54.5 94.5 46.6  s  28.5  -  48.0  = s  19.8 57.5  3?  28.5  a  88.5 61.0  •  48.5  - 14 P r e s s u r e d e o r e a s e due to h e a t i n g a l o n e P r e s s u r e d e o r e a s e due to p o t a s s i u m hydroxide Total deorease in pressure These r e s u l t s show t h a t  =  27*5  -  12.7 40.2  a  the gas a b s o r b s i t s own  volume o f o x y g e n and l a t e r l o s e s h a l f  it  volume  a b s o r b e d i s p o t a s s i u m and presumably oarbon d i o x i d e . In the f o l l o w i n g a n a l y s i s the e f f e c t s and p o t a s s i u m h y d r o x i d e  of  a s shown above were  P r e s s u r e of gas from f u r n a c e * " M a f t e r potassium hydroxide « H » « treatment with copper H n " a f t e r again t r e a t i n g w i t h potassium hydroxide T h i s a n a l y s i s shows t h a t t h e gas l o s e s  oopper separated.  -  140.0  -  137.5  3  74.0  -  6.0  approx-  i m a t e l y h a l f i t s volume t o t h e copper and h a l f to  the  potassium hydroxide. In t h e f o l l o w i n g a n a l y s i s cool  l i q u i d a i r was used to  t h e gas b e f o r e t r e a t m e n t w i t h t h e  potassium  hydroxide. P r e s s u r e o f gas from f u r n a c e " • " after liquid air H n H " removal o f tt liquid air " M M »» treatment w i t h oopper w  * » » • • «  » • « • « • «  liquid air  treatment w i t h potassium hydroxide  =• ,  147.6 141.0  .  147.6  -  100.0  »  15.5  «  25.5  - 15 This shows that the original gas is not appreciably condensed  by liquid air and that the same amount is  removed by potassium hydroxide as by liquid air.  A  small leak was discovered in the potassium hydroxide bulb but the experiments could not be repeated due to lack of liquid air* It was suspected that carbon had been deposited on the copper during the heating of the gas*  To test  this oxygen was heated with the copper slowly. of it was absorbed but a five percent  Most  residue was  almost completely absorbed by potassium hydroxide. This was repeated several times with the same result. A rough spectroscopic analysis of the gas was taken.  A spectroscope tube was attached to the  apparatus in the position of the oxygen generator and the spark spectrum of the gas examined.  The tube used  was of soft glass and not entirely suitable for the work.  Water vapor was given off when the discharge  had been passed for a few minutes giving rise to the hydrogen lines.  For the first few minutes a pure  spectrum of the gas was attained.  It was blue in  character indicating the possibility of carbon monoxide but mercury vapor from the MoLeod gauge obscured the hand spectrum of any other gas present. nitrogen lines were found initially.  No hydrogen or  It is planned to  - 16 oonstruet a new py rex tube and photograph the spectrum 'i  of the gas. Mercury vapor will be removed by a liquid air trap since liquid air does not condense the gas appreciably.  Discussion of Results. A brief summary of the facts to be accounted for in identifying the gas shows the following: 1.  The gas was formed at a temperature of 1000° C and a pressure of approximately IxlO"3 cms.  2#  It was produced at a slowly diminishing rate but was still formed in easily measurable amounts after practically three months of constant heating*  3.  The gas was collected at room temperature, approximately 20° C , and left at this temperature for some time before analysis.  4.  The gas was not appreciably condensed by liquid air*  5.  Only a small percentage is the gas by solid potassium practically all the gas is with red hot copper in the potassium hydroxide.  6.  Hot copper removes part of the gas and the residue is now almost completely absorbed in solid potassium hydroxide* The same amount of gas wa ioh is removed by potassium hydroxide is condensed by liquid air.  7.  The gas apparently unites with its own volume of oxygen and afterwards loses half its volume absorbed in potassium hydroxide.  absorbed from hydroxide but removed by heating presence of solid  The impossibility of condensing the gas with liquid air limits the number of possible gases to very narrow  17 limits.  Of possible gasses the rare gases nay be ruled  out by the reactions which this gas undergoes.  Oxygen  would be completely absorbed by oopper alone and would not unite with itself.  Hydrogen Is eliminated by the  spectroscopic evidence and in addition any water Taper formed with oxygen would be easily detected by Its behaviour in the Mcleod gauge.  Nitrogen is also ruled out  by the spectroscopic evidence and the faots of the reactions.  The only known gas then whloh fulfills the  first Six conditions is carbon monoxide.  The volume  change with oxygen can hardly be reconciled with this hypothesis but it is just possible  that oarbon dioxide  condenses on the walls of the quartz tube*  The total  volume change over potassium hydroxide fits in with the oarbon memoxide hypothesis. The behaviour of the hot gas with oopper is interesting if the gas is oarbon monoxide.  The pressure  changes as found in this research and that of J. A* Harris show that the volume of the gas decreases one half when over hot copper.  This would indicate that  the following reaction takes plaoe with oopper as a catalyst i ( 2 oo  .—5*  c -f oo 2 ).  M. Berthelot*6'  observed that when oarbon monoxide was heated with oopper in a sealed tube at 550° C oarbon dioxide was formed and carbon deposited.  Apparently this reaotion gees to com-  18 pletion under the conditions prevailing in the quartz tip. She gas then is almost entirely oarbon monoxide with a small amount of carbon dioxide and a small residual gas probably nitrogen although it may be due to gas from the copper tip. It seems possible that traces of carboifundum  are  formed in the manufacture of the quartz and that this slowly decomposes at the high temperature and low pressure used reacting with the nitioa to give off oarbon monoxide. (7) This reaction according to Miller proceeds vigorously at 2000° C and hence at the low pressures used some reaction vaould take place.  This hypothesis w uld account  for the uneven indention of the gas since small pockets might be formed and be suddenly set free.  The carbon-  undum near the surface would turn off the most quickly and the rate would gradually fall off.  Summary* 1.  A gas been found to be given off by quartz at 950° C and 10""3 ems* pressure and its rate of indention measured.  2.  This rate slowly decreases but is quite easily measured after three months constant heating.  3.  No equilibrium pressure is reached within the range of pressures measurable by the apparatus and practically no decrease in the rate of pressure increase is observed with increasing interval pressures.  - It -  4*  The gas appears to be carbon monoxide arising from traoes of oarborandum in the quarts but sons evidence Is oontrary to this assumption. In conclusion I wish to express my appreoiatlon for  the help of Dr. Marshall, under whose supervision the research was oarried out, ozpeoially in the construction of the apparatus necessary without whioh this work would hare been impossible.  I alao wish to thank Dr. Shrun,  of the Physios Department of the University, for his help and advloe in connection with the spectroscopic work.  1,  J. A* Harris, Thesis for the degree of Master of Arts, University of B.C., 1923.  2.  Sheppard - Journal of Geology 85., April 1925,  8.  0. Xraus, Jour* Am. Ohem. 3oo. St, 2165, 1917*  4.  Ouye and Hermann, Comptes Rendus,159, 184, 1914*  5.  Llnd and Bardwell, Jour, Am. Ohem. Soo. 47, 2678, 1925.  6.  M, Berthelot, An. Ohem. Phys.(7) 22, 808, 1901.  7.  J. W# Mellor, Treatiee on Inorganic and Theoretloal Chemistry, (Longmans and Oo•)  >  

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