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The preparation of the four-mono-brom-normal-valeric acids Johnston, Frederick Blaney 1928

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j U . B . C . L I B R A R Y *CC. HO. THE PREPARATION of the FOUR-MONO-BROM-NORMAL-VALERIC ACIDS. FREDERICK BLANEY JOHNSTON* A Thesis submitted for the Degree of MASTER OF ARTS in the DEPARTMENT OF CHEMISTHY. THE UNIVERSITY OF BRITISH COLUMBIA. APRIL, 1928. BY TABLE OF IMTPODUCT IO:T. ^V-l* • . 31 i; r» - . Discussion '•£ s:> .e of . t '.) :>ds •<r ii-io ;-;»Li:ir of Uu? f'-ur ao-io-bro;:-n-valeric acids, a-vl •ne thod 2 f i.o.a u ssd . SXP^HXT^TTAL. A. The i^lcin^; of oC-brom-a-valftric °oL i . B. -brom-n-valeric ac id. C. T-bro;t>-n-va 1 er-ic acid. D. 5 -b roa -n - va l e r i c acid. S. An attempt to make a -brom-proprionic acid, r-iv? l ives11 3ation of the propert ies of the compound obtained. THE PREPARATION OF THE FOUR MONO-BROM-NORMAL VALERIC ACIDS* INTRODUCTION. In cer ta in work undertaken in th i s laboratory the four mono-brom d e r i v a t i v e s of normal v a l e r i c acid were required, that i s - theory*?, v , and S compounds. Only one of these, the ex-compound, could be bought. Therefore the preparation of the other three was undertaken here . Search in the l i t e r a t u r e y ie lded a sui table method f o r but one of these three , t h e V - a c i d . For the other two, the methods g iven were not prac t i cab le f o r the amount of the acids needed f o r the fur ther work. For the sake of completeness in th i s research, some of thee*-acid was a lso prepared. Analagous cases of the d i r e c t 1 ^ bromination of normal-butyric acid and i s o - v a l e r i c ac id " to g i v « the corresponding <X-acids suggested a s imi lar procedure in the case of the normal-va ler ic ac id . Ixperiment confirmed t h i s . A second method was suggested by the common method of using red phosphorus and bromine^ in the making of th i s c lass of compounds. This was a lso confirmed by experiment, and l a t e r h much the same method was found in a recent paper . Theytf-acid presented a d i f f i c u l t problem, and f i n a l l y a combination of former methods had t o be used. The es t e r of the c(-acid was made into the unsaturated ya "pent en''-acidS and on t r ea t ing th i s with hydro-bromlc acid the/tf-brom v a l e r i c was obtained® An attempt to make the « - b rom-va l e r i c eater from the corresponding acid by the s i l v e r sa l t method of making esters was not very successful . The Y-ac id was made according to a procedure given in the l i t e r a t u r e ' ' ^ . This was, in b r i e f , theformation of a l l y l - a c e t i c acid and the addit ion of hydrogen bromide to th is to y i e ld the Q required va l e r i c acid . A comparison of two ways of making the a l l y l - a c e t i c acid was made, and some s l i ght improvements made in the procedures. A small quantity of the va l e r i c acid was also made from Y -va lero- lac tone The methods given f o r the making of S-brom-n-valer ic acid were too cost ly to allow the preparation of any considerable amount of the ac id . The f i r s t possible method that suggested i t s e l f was to make one bromine only of the symmetrical 1-4 d i -brom-butane undergo a G-rlgnard's react ion . From th is l a s t -named compound have been made adiplc and sebacic acids by the use of su f f i c i en t magnesium to form the metal complex with both ends of the compound11. Since 1-4 dlbrom-butane could not be obtained a start was made las t year in i t s manufacture. I t was hoped, by F i t t i g ' s react ion, adding one mole of sodium to two molecular weights of ethelyne blbromide, t o obtain the desired compound. Repeated experimenting gave no resu l t s . Next was attempted the making of the same compound start ing with 12 butadiene, which was to be made from ethelyne and acetylene . ' - 13 i4 1-4 dibrom-butadlen had p r ev i ous l y Seen made from butadien I t seemed quite probable that this compound could be reduced to the corresponding 1-4 dibrom-butane. The descr ipt ion f o r the manufacture of butadiene along the proposed l ines being very meagre, i t was soon found that too long a time would be p required f o r the study of proper condit ions, so that attemf, was dropped. The lactone being used o f ten in the making of brom-acids by addit ion of hydrogen bromide, i t was decided to use S-va le ro lactone in the formation of the 5-ac id^° The required lactone was made by the aceto-acet ic es ter synthesis from 3-ch lor -a -propyl a lcoho l . Treatment of th i s with concentrated hydrogen bromide solut ion y ie lded the S - a c i d . As a matter of interest ,an attempt to makey^-brom-proprio-nic acid from ethylene dlbromide was made, th i s being analagous with the procedure t r i ed in the case of S-brom-valer ic ac id . EXPERIMENTAL« A. of-brom-n-valer lc Ac id . As already stated in the introduct ion, oc-brom-butyric acid has been prepared by the d i r e c t broicination of n-butyr ic acid? One molecular weight of the acid was sealed up in a g lass tube with one molecular weight of bromine. The tube was then heated. The products of the reac t ion were oc-brom-\'aleric acid and hydrogen bromide. 10 grams of n - v a l e r l c acid were sealed ?/ith 16 grams of bromine In a tube. The tube was heated in a furnace f o r several hours at II0°C. The tube, a f t e r coo l ing , was c a r e f u l l y opened, since a considerable volume of gas v/ould be formed by the reac t i on-CH jCH 2CH 2CH 2COOH + Br2 CH^CHOCI^CHBrCOOH +• HBR. The bromine remaining was expel led by heat ing and the acids f r ac t i ona t ed . Some unchanged n - v a l e r i c acid was recovered, and a small amount of * -bronaua-valer ic acid, bo i l i ng -po in t -about 135° at 30 mm. pressure. oC-brom-n-butyrlc acid has been prepared by the act ion of bromine on the n-acld in the presence of red phosphorus, and the subsequent hydro lys is of the ot-brom-n-buteryl bromide so formed with the exact amount of water required? 10 grams of n - v a l e r i c acid were placed in a f l a sk provided with a r e f l u x condenser. 2 grams of phosphorus were added and then bromine, gradual ly , u n t i l f i n a l l y the mixture remained reddish in colour on he?.ting, Th.; jhos h-srus xxy-bromide formed was f i l t e r e d o f f and just enough water Pi led to decompose the c < - b r o m ~ n - v a l e r y l bromide. The mixture was then boi led f c r a few minutes. A f t e r drying over concentrated sulpnuric acid and so l id pots .-slum hydroxide in dess lcators , the o i l was f ract ionated, and as before a small amount of both the o r i g ina l acid and oC-brom-n-valeric acid was obtained. 4 The method l a t e r found , which corresponds very c lose ly with th is l a s t , i s , b r i e f l y , as f o l l ows . The n -va l e r i c acid Is bromlnated, as be fore , in the presence of red phosphorus. Tne mixture i s poured into ethyl alcohol and the ester of the brom-acid i s formed. B. ^?-brom-n-valeric Acid. No method could be worked out which would be better than those already in the l i t e ra tu re f o r the preparation of the ^ - a c i d . Therefore, since theoc-acid was eas i l y procurable, i t was decided to t ry to make th is into the corresponding* acid with a lcohol ic potassium hydroxide, and then, by treatment of th is unsaturated acid with hydrogen bromide solution, to get theytf-brom-valeric ac id. However, I t was not known whether the potassium salt of the ex-brom-acid would readi ly sp l i t o f f hydrogen bromide, so that th is method was given up f o r one r" already t r i ed out elsewhere? In th is one, c( -brom-n-valeric ester was ref luxed with quinol ine, when the ester of the required unsaturated acid was obtained. Accordingly, some of th is acid was so prepared by th is method and subsequent saponi f icat ion v'lth potassium hydroxide gri£ a c i d i f i c a t i o n with sulphuric ac id . A f t e r extract ion and pur i f i ca t i on , the acid was shaken f o r several days with hydrogen bromide solution saturated at CTC. Une layer f i n a l l y resulted from which the /?-brom acid formed was recovered by d i lu t ing the so lut ion. The acid was extracted with ether and dried as was the o<-compound. An attempt to make the « -b rom-va l e r i c ester required by the s i l v e r sa l t method ?/as not so successful as this i s said to be. To 25 grams of acid was added a water solution of 43 grains of s i l v e r n i t r a t e . The s i l v e r sa l t was f i l t e r e d o f f and dr i ed . I t was then re f luxed with 50 grams of e thy l iodide, but the y i e ld of the a - e s t e r was very poor. The method was there fore discarded f o r the one described immediately before t h i s . (Note:- This acid was made by Mr. Guy Haddington.) C. y-brom-n-valeric Acid. A f t e r consideration of methods which presented themselves and of such as were found in the l i t e r a t u r e , i t was decided to make the Y-acid by a method already w e l l - t r i e d . By the malonic ester synthesis a l l y l bromide was converted to a l l y l - a c e t i c acid , and th is treated with hydrogen bromide y ie lded the Y -ac id . 23 grams of sodium metal were dissolved in 300 grams of absolute ethyl a lcohol , d i s t i l l e d over l ime. Through a r e f lux water condenser was added just one mole (160 grams) of malonic e s t e r . A pasty, white mass was produced. ^COOSt XOOEt NaO&t + CHp • NaHC + EtOH. >xGOOEt COQEt 7 Sl ight ly more than the calculated amount (120 grams) of a i l y l bromide was then added. The reaction wa3 accompanied by the evolution of considerable heat. CK2=CH-CH2Br + NaHC(COOEt)2 * CH2»CH-CH2-CH(COOEt)2 JkvH. The reaction mixture was then heated a short time on the steam bath, re f lux ing , and i t vms found to be neutral . The excess a l l y l bromide and the alcohol were d i s t i l l e d o f f on the steam bath. ( I f a l l the alcohol was not removed here, i t caused d i f f i c u l t y in the drying of the ester l a t e r . ) Su f f i c i en t water was added to d isso lve the sodium bromide, and the ester was extracted with ether. The ethereal solution was dr ied, the ether d i s t i l l e d o f f , and the ester fractio&ated, the portion bo i l ing from 218-225° being retained. (Yie ld-70^ theo r e t i ca l ) . The es ter was treated with twice the theore t i ca l amount of concentrated potassium hydroxide solution (1 .2 gram a lka l i to I gram of water). A f t e r two hours heating on the steam-bath, the ester was completely saponif ied. CH2«CH-CH2-CH(COOEt)2 +2K0H CH2=CH-CH2-CH(CoOE )2+2 EtOH Here a departure was made from the method of the l i t e ra ture in that a step was l o f t out. Prec ip i ta t ion of barium a l l y l -malonate, a3 advised, caused trouble, as the barium hydroxide also formed caused much trouble. So the a lka l i solution was neutralized with the calculated amount of sulphuric acid. C5H5-CH(C00I)2 + H2S04 * C3H5-CH(GOOH)2 K0SO4. Since a l ly l -malonlc Acid is soluble in water, the solution was extracted upwards of ten times. Even with th i s , . the amount of acid obtained was only 20$ of the amount calculated from the o •J * ester used. The acid was dried over potassium hydroxide a f t e r r eo r ys ta i l i z a t i on from ether . Melt ing-point of c rys ta ls - 103°C. The a l ly l -malonlc acid v.-a a then heated on an o i l -bath to 130°, or, as was found equally sa t i s fac to ry , with a small flame, thermometer in the l i qu id , un t i l no more gas was generated. F inal ly the l iqu id was f ract ionated, the f ract ion between l32° & 134° being co l lec ted separately, - t h i s is a l l y l - a c e t i c acid. C3H5-CH(COOH)2 C3H5-CH0COOH + C02. A solution of hydrogen bromide, saturated at O^C, was prepared. Two volumes of this were shaken fo r several days with one volume of a l l y l - a c e t i c acid. Gradually the two merge into one. CH2rCH-CH2-CH2-COOH + HBr CH3-CHBr-CH2-CH2-CU0H. V The Y-brom-valeric acid was obtained by d i l a t i ng the solution and extract ing with ether . The ether being d i s t i l l e d o f f , the acid was washed with water, and dried over concentrated sulphuric ac id . On standing, the acid became quite black, but th is colour can be removed with animal charcoal. Tnen tbe f rac -t ionation of the acid was attempted, i t was found that this could not be e f f e c t e d , even at 30 mm. pressure. In spite of a l l precautions, the 11 qui? burvpei. A very f ine j e t of a i r was introduced beneath the surface of the l iquid by means of a cap i l lary tube, and glass Ss were also used, but to no purpose. Since 110 bo i l ing-po int is given in the l i t e r a tu r e , th is same d i f f i c u l t y has orobablv been encountrerl be fore . V V In general, the malonic ester synthesis g ives a better y ie ld than does the aceto-acet ic synthesis, but recent work has g i v en -us v.-ry yi=?ld r, 3 "• ha: i „.• • ^i'.'.-J - - b. iJ. J •.-•.•. . 1 j i •! . \j j n • ! n i f ' d r l r l c X" . T i t . ; e >o l i - g , " .2. r •-•.«> . ,-r • ,. • , _ 0 . : ^ •. • -,-. - • „ ."! ... ** - ^ . • i'v £ .» 'J.T'.t 3 1- ->\" ± , /COCH-r ^COCH-T.TpO^ :-'; + GH0 Nr-.CH ' + E OH. ^ COO'S' "^COOEt Thr -ug i P. r. f l •:: '..--^r •:•: > ~0 .->? a i ; y l • r x i i d . •ere ad ^ s l > o l y . /COCH- xCOCH-CHo«CH-CHo3r + MaCH ' CH0«CH~CKg-CH " + -Te.3r. vCOOEt vCOOEt The mixture -p.s theo re "luxe 1 Mat51 it. o *> -1 r eac t i on . -The a l coho l - j?3 i i s t i l l e - . ; o f f on a str am-ba.f h, wss added to d i s s o l v e the sodl^e 1 ro -ed io the : -voti-and the a l l y ! ace t o - a c e t i c e s t e r extract ' : - ' v l '• h - t h e r . Af te r '.he e t h e r e a l e x t r a c t ha 1 besn dri-.d wi th anhydrous pota.ee-lee.:. ac id carbonate, the e ther wa a - l i s M i l e ' the st er-f r a c t i o n a t e d . The ; .orti^n V d i i n ; h. t.„ , 200° an.? 2 1 3 C . c o l l e c t e d , be ing a.l -.ost pare -it:v. Y i > -1 il - 70 " . The procedure next fol"1 >w- in the l i t . fu ture was to r e f l u x the e s t e r wi th 3-4 t i r . . ? the t h e o r e t i c a l poount of potassium hydroxide in a l U M - . oat- r . Tn • s v.?.. t r i e d and ht J. • ielde-"* no aid!1 1 ace t i c ac id -/hen tne el;. tor.- s f . irtoer t r ea t - ed , but only a. mixture of o ther , u d e s i r ed products-. lText w s t r i e d a mod i f i c a t i on of t u i s method. AO rirams of potassium hydroxide ./ere d i s s o l v e d In IS grama of a l c oho l , two _ .r-3 r e s u l t i n g . The a l l y l ace t^ -aCc t i c v s t e r ^dd1'd r rad-o a l l y , when the too l a y e r of e s t e r and alcohol. i l " v ; l y d i s s o l v ed Wit COCH-C-Hr-GpT + 2K0H + CrHr-GOOK + CH.-COOK + St OH. gooe^ " Tui-. reaction . •-.£ j"fUxtd int.) 250 o . c . of v/^itr and the acetone vviioie ei'.t : net': 1 ,;ith eth-.r t0 ro .ore .®ri7 ^ i i - l i.'i.n + •• 1 -v. - J —V -L - - - "'• I - t » for-. e en* unchanged est*: r . The aeneous solution ••v3 ac id i f i ed '-.-it.:; sulphuric ^- id a>-d thf-. a l l y l tic a c t ! then e x t r a c ' : : v,r' t • e.thvr. ca lculate" ecter used, a e l i was dr ied and t r e a t s as in the previous method. Since i t had teen decided to use one of the methods of the l i t e ra tu re to maice the Y-brom-val< r i c acid, an attemot was made to obtain i t through the use of the Y- lactone. A b r i e f TO summary of the combination of various procedures in this synthesis f o l l ows : -100 grams of cane-sugar were heated for twenty-four hours with 500c.c. of 1:4 hydrochloric acid on a stean-bath. Phe mixture was f i l t e r e d and 35 grams of sodium hydroxide added gradual ly . The whole v/«s then evaporated " in vacuo" to IOOc.c. and the sodium chloride which s- parated out f i l t e r e d o f f . The laevu l in ic acid vms e ;tr acted with ether and f rac t i onated- ' H.P.- I40°- I70° at 15-30 mm. 34 grams of ?c1.d were dissolved in 12 grams of sodium hydroxide in 100 c . e . of 95,% ethyl alcohol , in a f lask with a ' re f lux condenser attached. During an hour, 13.3 grams of sodium metal in f ine s l i c e s were introduced into the mixture with continual s t i t r i n g . A f t e r a l l the sodium had been added, 30 c . e . T T . :>f the a lcohol 12o t i l l ed o f f . Trie residue wss t reated r i ' .h 25c. o. of ivaier to dec oncost the so-:!' ul. thy l a t e formed in th< react ion and the alcohol x-. su i t ing removed :'y d i s t i l l a t i o n . A f t e r coo l ing , the f i x t u r e rega in ing ••?.?.3 a c i d i f i - d w'.th 7 . tc:.c of d i l u t e sulphuric ac id . The ye l low o i l f l o a ' ivi; on two was removed, the aqueous sol .it ion neutra l i sed with sodium carbonate and extracted repeatedly with e ther . The o i l obtained was f rac t i ona ted and the lac tone , " . P . - .11*3-13^° at 60mm., co l lected. On heating th i s lactone with saturated hydrobromic acid in a sealed tube at 100°C, the Y-bror ; -n-va ler i c acid v;as obtained. The y i e l d s a l l through were very poor. D. ** 8 -b r oa -n - va l e r i c Acid. As has already been stated, i t via<3 hoped to make the S-acid fron 1:4 dibrombutane. however, no method could be evolved which would v i e l d s u f f i c i e n t of th is l a s t com-oound f o r the purpose in v i ew . Theo r e t i c a l l y , the eas i es t way of making the butane seesaed to be by F l t t i g ' s reac t ion , according to the equation-Br-gH?-CHc.-^r 2TTa 3ri-CHo-CK?-Br Br-l GH2)4-Br + 2Na3r. A number of t r i a l s , made under vary ing condit ions of temperature and d i lu t i on gave no r e su l t s . The use of metyl cyanide as a c ca ta l vs t did no /rood, i t mav be that the lack of expected v / v r esu l t s i s accounted f o r by B i s c h o f f ' s "Dynamic Hypothesis". A second poss ib le way of making i : 4 dibrombutane i s the reduction of dibrombutadien. This l a s t compound had already been made by what seemed a simple method, so an attempt was TO made to redupl icate the experiment. Ethylene was prepared by passing ethyl alcohol vapours over anhydrous aluminium sulphate, contained in a combustion-tube heated to 350°C.IThis procedure g ives about 99% y i e l d of ethylene. Acetylene was male from calcium carbide. Any arunonia V V V present in i t was removed by bubbling i t through water, i t was then freed from any hydrogen phosphides by passing through a suspension of calcium hypochlorite in water. At th is point, the ethylene and acetylene were mixed by bubbling them into a f lask containing more water, thus allowing the admixture of the gases in equal volumes. The mixed gases then passed over granular calcium oxide in a tube into a porcelain combustion-tube heated to 500°-600°C which was f u l l of fragments of pumice-stone. The outflowing gases were cooled in a sp i ra l condenser In a f reez ing mixture ( -20°C ) . A small y i e l d of butadien, 3 . P . - -5°C, was obtained, but not su f f i c i en t to be of use. For lack of time the attempt was abandoned. The method f i n a l l y used f o r the S-ac ld was the treatment of the 5- lactone with assaturated solution of hydrobromic acid. The lactone was made from 3-chlor-n-propyl alcohol by both the malonic ester and aceto-acet-ic es ter syntheses. The required chlor-propanol was made by a method which proved quite sa t i s fac to ry 1 ^ . Red i s t i l l ed trimethylene g lyco l was saturated in the cold with dry hydrochloric acid gas. The increase in volume amounted to about one-fourth of the or ig ina l volume of the l i qu id . At f i r s t the mixture was sealed In -tubes 13. th--n --.ated '»n a steam-bath, '. ui i a t t r I t was ?rw.i t;.»*t so l i t t l e pressure was developed that ordinary r~agc.it botti--s with, rubber corks wire-J. irt "'ere quite strong enough. The heating was continued f o r X'our hours, the containing vessel cooled and opened. The l i qu id , now viscous, was agMn satur-ated with hydrogen chlor ide , and heated as N-'.'ore fo r two hours longer . I t was then d i s t i l l e d . There was a great v.Un ; towards bumping, even with glass beads. This was best r<•;;>:••?.led by gently tapping the 3ide of the f rac t l ona t lng - f l ask unt i l a l l the hydrogen chloride had cone o f f , when the bumping ceased. The f rac t ion bo i l ing from I60°- I62° was co l l ec ted , being the chlor-propyl a lcohol . The procedure from here on was,in both the malonic ester and the aceto-acet lc es ter syntheses, exact ly the same as that fo l lowed in the making of the Y-acid, the chlor-prooanol being substituted f o r the a l l y l bromide. In ne i ther case, a f t e r the addition of the halide to the mono-sodium ester , was the-pur i f i ca t i on of the resul t ing compound attempted, since no information could be obtained about e i ther of th*m. They were used in the fo l lowing reactions as i f pure and were found to act f a i r l y we l l . The f i na l product of each react ion w*s 8-hydr oxy-n-valer ic ac id. On d i s t i l l a t i o n , th is y ie lded , by B P. 2/40- 22 0' <xt ico the loss of one molecule of water, 8 -n-va lero- lac tono. This A was heated with saturated hydrobromic acid in a sealed tube to I45°C. The mixture was d i luted and the S-trom-n-valer ic acid extracted with ether. IT.P. of the acid I t . TP j3-bro:..-propriooic Acid. Iii order to get an idea as to bov/ the proposed synthesis of S - t i ' i - v a l e r i c acid fron the dibrom-butane n3.ght go, an ttempt ".-as made to obtainy0-brom-propr3onic acid 1:y drignard's reaction fr >.„ ethylene d'bromide. To ?•:• -ran'S of ethylene d i V - y . l i e in ?00c.c. of ir- ether was aide I te-hal f mole ~ef magn '.si am, in the for-:;. of r i 'oh on, thr a re f l a x condenser. Trhen a l l the ui-. ta l had disso lved, the f lash v;as put in an ice-bath, and a steam of carbon dioxide bubbled through the l i qu id . At the end of SO minutes the temperature rose suddenly fro-- 2° to I5°C, and a so l id set t led out. The carbon dioxide -jas passed in. un t i l no more so l id prec ip i ta ted . The two.- react ions v:ere presumably as f o l l ows : -Br-CH2 - C Ho - Br + Jig * Br-OHo-GIb-hgBr Br-CH2-CH2-i:gBr + COp + 3r-CH2-CH2-C00Mg3r. Three times the theore t i ca l amount of sulphuric acid, cooled, v/as added, since just exactly the theore t i ca l amount did hot dissolve the so l id . 'Tien extract ion of the expected I acid *;/as attempted, three d i s t inc t layers of l iquid resulted. The top one consisted of ».• ther plus a s'.uall amount of t thyl-ne dibro d.de. The middle lay-..r contained sows ether -*nd a Dure ° 1 l i qu id which bo3led entir- l y at 73°-73JG at 8-IOcm. This 1 l i qu id './as pe r f ec t l y ..ilscible with ether, soluble In /.eater, i t s f reez ing-point ./as -AO0, aul bo i l ing-po int 1 2 3 at 760mm. I t s density , determined by depression of f reez ing-po int of water, was 1.73. O '•'!•• ,< r.M i. ~>n &> . I . 1 'J . „ .... •»- T V n ' v - V ' 11 ••*> r - i t VI ;(•>'• 1 » • • o t h i s search. To Dr. Ko.ej 3, Tie ad *£ the De:.si-h,e.)t of Che mist x-y at the Univers i ty of I l l i n o i s , els">, 1 a... indebted f in formation i- • re j?rd to the man a fa c -ure '<f 1:4 dlbrom-butone, as '.veil ^s to Dr. Johnston, now ;-it oo rne l l , wno -un f i l ed me with information in the same 15-v.;. La oh of L t u'rvenled th<- use of this in for:-at ion.. UBC Scanned by UBC Library j^ TjJ-ITTT'pVM QT? C ^ NAUHA'TU. L IE.Hi' T'8 A .pier. TRIE DEL, T.!ACLUCA. A •VU'-.l en 120. P . 233 A anal en 171, ° Zi Q o I .ivcj i . s-jrv. ft : i / - , .  T r^r-y • * ! > P * I 4 . 2. Annalen 267,i,<.l47. 'T0I *~:ARD. A a al e t 3 .i 2, o . 161. I'lriAZL.. 3o r i ch ,e 7-4 , p. 404" . 5. r." fpE, HO"TI3, LOT 2. • i ' t . 7 ITT , SP5T! CTK. A a ; - > - •? — at v. _ , • A ;OrTRAO, 3ISCHOF?. Awns a • - n - • - a'. - t "  .-I.V i.«-!; i w J't , • 1 iu i 3. FiTTi 'r, Mb*S5h;-HSCH7IDT. Aon&l* ZSIDL£R. Annalea 9. F I T T A n n a 1 e n 2Oh,p.94. 10.taxLOH, WL03E. J .A .C.S. 1917,0.427. SKHUBTTS,SAH. J .A.C.S. 1926,p.3155. LO'JIS H31TRI. Cot rotes Ren-lues l02,p.3o3. II.OrAUTHIER. Annales -Is Chiaie <6), l6,.p»350, I2.27RTHEL0T. Annales Cni-'.ie 14) ,9,p*466. PRU1TI2R. Annales Chi ie U 7 ) , 17,p. 17. 17.THIOLS. Annalen 3"3,pp.374-779. 14 .STRAUS• Beriente 42 ,p.277-3. I^.IRIUSR. Conotes Reniues 117,p.553. TX i"'T 'T75; A • • , r 1 T .:> 'T,"' 1 w . e i_v.' V .j . fUi-J 1,-a. —J * , w « . 17.7:720.11. A/rialee de Cniiuiu ( 7 ) , 14 ,p.491. 


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