BY L.
31. D E S S I S A S D F. E. H A S C E
Gernianiuin tetramethyl waq prepared hy the Grignartl reaction. In preliminary e~perimentsit was found to he practically inipossihle to separate the germanium alkyl from ether in the vacuum fractionation apparatus.? This made it necessary t o depart from the usunl procedure so that the amount of E
6
i ether in the product might materially he lesqened. The apparatus that TVRS designed for the purpose is shon-n in Fig. I . The round bottom flask3-4 of one liter capacity carried a sepsratory funnel B fused through the side as shown,
IO j 6
L. >DENNIS I. A S D F. E. H h N C E
and a condenFer c'. The stirrer S passed through a mercury seal. An upright condenser D was fused t o c', and the receiver E. attached t o the lower end of D bv n cork? carried R calcium chloride tube F. TxTenty grams of magnesium turnings and 2 0 0 cc. of dry ether were placet1 in -A, and the mixture was cooled with ice a d salt. K a t e r was started flowing through condenser C'. Eighty gr:inis of methyl broniide was dissolved in about IOO g. of dry ether at - 20'. This solution iva%slowly introduced into A through B, the contents of the flack being vigorously stirred during the addition. VThenthe reaction hecanie quiet. the contents of A was heated and the ether was refluxed for about 3 0 niuiutea. C' n-ac emptied of water. nater was turned on through D, antl the h d k of the ether n a s distilled over into E, and was removed. The stirrer n-aq then rcmowd, flask h \vas closed with a cork, the Grignard reagent in -1n a s heated t o IOO', and ~ u c t j o nTTRS applied at F to remove as much as lio~sib!eof the unconibined ether. The stirrer TTM then replaced in the neck of X,m t l 1 0 0 cc. of xylene. dried over sodiuni, ivaq nddetl through B. TT-ater ivaq turnell on through C', and the content. of the flask 11-asstirred antl n-as heated until the xj-lefie quietly refluxed. Germanium tetrr tl.loritle, one niol to eight moles ?tlgCHaBr,was then dowly introduced through the separator?- funnel B, the contents of the flask being kept warm. K h e n the rwctioii -sa. complete. the water was JTithdrawn from c' and the mixture of germanium tetramethyl and the ether IT-hich iq set free from the Grignard reagent in the reaction nas distilled over into E. The xylene was held back by the empty receiver C. The liquid in E 1va9 then fractionally tlisti!led through a nine-ball column. The greater part of the liquid p::ssec\ over at ja'. Careful antl prolonged fractionation with the vacuum apparatus 01 Laubengayer and Corey failed to >ellarate the ether from the alkjl. In the stud>- of germanium tetraethyl, the zuthors had found that that coinpound \vas not affected by cold, concentrated sulphuric acid. C'onsequently the mixture of the tetramethyl antl ether was treated with about twice it. volunle of cold, concentrated sulphuric acid. The ethyl sulphuric acid separated as a heavy, syrupy layer which n a s easily drawn off in a separntory funnel from the lighter germanium tetramethyl above it. The latter substance TWE washed with v-ater several times In the funnel and lvas then dried over calciuni chloride. An arc spectrum photograph hy Professor Papish shoned the product to be practically free from :ill impurities. A second preparation of aboiit the same amount (6 j cc) n-as found t o be equally pure. The two samples TTere separately distilled with a ball column. the bulk of the material passing over in each case at 43.2'. The constant boiling fraction of the first preparation mas brought into bulb B1, Fig. 11, of the vacuum fractionation apparatus, and that from the second sample into bulb Be. The physical constants of the two samples were determined separately. Each was Qubjected to careful fractionation in the ILsuhcngayer and Corey: J. P h p . Chem., 30, 1043 (1926).
apparatus, antl those portions showing liractically the same vapor tension at oo n-ere retained, while the other siiia11 fractions of different' vapor tension n-ere reiiiovetl from the apparatus. T7ccpor Te~isiouo t os. The values observed in ten determinations with each sample shon.ed ;I niaxiiiiuin variation of 0.5 iimi. -%v. 159.3M I H . . C'arbon and hydrogen were determined by comhustion with co1)per oxide in a current of air. The app:iratus which vias used, antl which Tve regard a.: a tlistinct improvement oyer that employed for the analysis of geriiianiimi tetraethy1,l is shovn in Fig. 2 . The l j d h -1, into which the sanip!e is lxought. is provitletl with two stopcocks as shon-n. nntl thc elid of the neck is ground t o fit the slipjoint E, :\ slipjoint of the apparatus wect ion tletermiiiing the gernianimn '\see later) ,
nncI a slipjoint {not s1:on-n in tlic t!r:iwinp 1 of the ~ - a c i i i i i i ifrnctimation apparatus. -4 wniple of tlie yeminnium tc:ramcthyl i n s first tlistillecl into liulh F of the vaciiiiiii ap!)aratus. $:) was closet1 nntl the brill) was detached ::ntl weighecl. I t ivas then :ignin tittnchetl t o the chain at E antl n suitable portion of it a-a? tlistilletl cn-er in thc iisiinl m r n n e r into the hulh -1of tlie npparntuc for nnnlysi.. The tn-o stopcocks on -4 n-ere closed antl it was n-eighetl. The lnilb I.' or' the ~ - : i c i i i i i i i npparatiis TYRS neiglietl ag&n, This iiicthotl g:i\-e tloiihle n-eighinp on each saniple. Buih -1w s then ::tt:?che:l to the npp:m-ttns as s1ion.n in Fig. 2 . 11 and S :ire tITo heating unit.; of an electric coinbiistion furnace. -4 single quartz tube, filled with copper oxitle. passe(.l through 110th iinit5. The iisiial absorption apparatus n-as attached t o the tiibe fit D. The furnaces n-ere brought' t o a temperature of :ilwut I 5 0 3 antl air m s tlraim through the apparatus through n purifying chain attached to C'. The current through unit 11 was then turned off antl the portion of the c o m h s t i o n tubc lying in S n-as brought' t o n bright red heat heyonc! the point H. The stopcock beyond C' was then closed, antl that of the purifying chain attached t o B, together with t,he two stopcocks of *1, a,nd stopcock F were opened. A1irwas slow1~-drawn t,hroiigh 1 carrying with it the vapor of the sample. This burned x h e n it entered the furnace S:but haelifire of the explosive mixture of alkyl and air \vi23 pre1
Dennis and Hnnce: J. ;lm Chrm. Soc.. 47, 370 !1925!.
all of vented hy the layer of coltl, closeip-packed copper osicle in 31. the saniple hat1 been carrietl out of ;1,unit 31 of the fiirnace was heated, ant1 the combustion \vas completed in the iisual manner. Gerniaiiiiini n-as determined by Iiringing a n.eighetl :iniount of the sample into liulh -4 and attaching that by means of the slipjoint to a 100 cc. flask containing a mixture of equnl mliiines of concentrated sulphuric acitl and fuming nitric acid. -4nupright contlenser W R S fusetl to the upper end of the flask. The ncitl mixture n-:is t2001eel t o : i \ ~ O l i T - 20' nntl the sample n-as sloir-ly driven over I)\- air pressure into the acitl. n-ater-118th was then brought up arouiid the flask, nntl the contents vas 1ie:itctl until oxidation was complete. The solution nnd rinsings were evnporatecl t o clryness in platinum, the excess of su!phmic scitl vas funicd off'. the residiie T V R ~ tlissolT-etl in x ten per cent. c-olution of potawiiuii hytlroxitic. an:l concentratetl sulphiiric acid ~v-asadded until the :icitl conccntrntion TWC: 6 S. (kriiinniuni was precipitatetl from this Pollition :is Gc&. the rci1i:iining steps of the determination k i n g as given by Dennis and Johnson.' Anal. Siil~s..0.1345.0.31.1.;. ('alctl. for (;e(('E3:3)4: ( ' - 0.0486.o.r1\3;= 36.17per cent. 1.1. 0.0122. c.o286=9.11per ccnt. Found: ( ' . 0.0486,0.1137: Xv., 36.1;per c r n t : 13. 0.012~;.0.028h:.\v. 0.12.: per ccnt. 5 1 . 7 1 per cent. Found: Subs.. 0.4866,o . h ; _ ~ 3 .('alctl.: ( ; e , o.?hhi.0.,;6&9= 0.2661.0.3688:a4v. 54.691:er ccnt. Densit!/ of Gel.)tiatiiiotl Tct~oiictli!jl1 1 8 f h s . T-npor density determinations were macle with the vaciiiiiii apparatiis of Lauliengaper nncl ('orey in the iiianner clescrihed hy Dennis, ('ore? niitl lloore.' Tn-o determinations gnve fcr t,lic Twiglit of I liter under stsntlnrtl conditions, 5.932 g. and 5.036g I T , , L;,o,3.i p. Thc calculated density is 5 . 0 2 4 g. Dettsl'fy ns L f q u i d . The tlensity of the liquid ~.aiiiple vas cleterniinecl at 0". Tn-o determinations gnve 1.003 anel 1.009g. per cc. The density as liquid may therefore be repartled c1: I . T 7 a p o ~Tetisioii. The vapor tension TWS detcrniined froin - 89' to +-+6.:' using the apparatus of LaulieIiga,yei nncl ('ore\-. i ?
Temp. ,"C Press., nim. Tenip.,'C Press., mni. Temp.,"C Press., mm.
-89.2 0.0
-12.4 73.2
41.6
--;9.1 -64.8 -49.0
0.8 - 9.6 87.9 43.0
718.6 j4o.j
-40.0
2 . 3
7.0
11.8
0.0
9.3
2 1 . 1
139,:,
342.3
209.j
-29.5 -21.8 24.3 41,4 30.1 .173,2
39.7
679.5
46.5 8.36.0
l?oiling Poitit. The hoiling point of germanium tetramethyl, as taken from the vapor-tension curve, is 43.4'. Index qf l i q f i , n c t i o i i . This was determined with an -4lbb6 refractometer. Four closely agreeing det'erniinations gave 1.3868a t 23.5'. 1
Dennis and Johnson: J. --Im,Chc~m.$or., 47, 700 (19251. Drnnis. Corcy nntl 1Ioorr: ,J. .lm. C'hrm. Soc., 46, 65; 1 9 2 4 ) . ~
J l e l t i ? i g P o i ~ ~ The f . melting point n-as determined in the tube R , Fig. 2 : of the vac.uuni fractionation apparatus by ohserving the temperature at which the solid and liquid phases n w e coexistent. Xgreeing results indicated that the melting point is in the neiphliorhootl of - 88'. Properfirs of Gcruici~ziuni T ' d r u m e t / q l . The siihstance is a colorless, oily liquid of a pleasant, sneetish odor soiiien.hat rpsenihling that of chloroform, hut quite unlike t h t of germanium tetraethyl. It Iiurns with n sooty flame which is yellow on the outer surface hut P ~ O T Y Ra deep-red inner mnntle. Gernianiiini tetranietli;\-l is more rentlily actetl upon liy oxidizing agents than i q the tetraethyl. Sitric ncitl slon-ly ositlizes it at 0'. Chlorine rapidly acts upon it in the coltl. hut lxomine attacks it nnich more slovly. Iodine did not seem to affect it' during n period of 48 hoiurs. ('oncentrated hydrochloric acid and concentrated siilphiiric acitl do not act upon it in the coltl. Germaniuni tetramethyl is solulile without decoiiiposition in alcohol, ether and henzene. It appears t o forin n constnnt hoilinp niisturc n-it11ether. hoiling a t a temperature slightly nhove 34'. Summary This article deals with the preparation of germaniiuni tetranicth>-l. its pnrification and analysis, density as gas. tlensity as liquitl. vapor tension. lioiling point. intles of refraction, melting point m t l soiiie of its cheiiiical properties. There i. a1w clewrihetl a iuethotl for mid+ 1))- comlnistion of a liquid containing carlion nntl liytlrogen. I tliicctr,
.I-(11, Yo?,/:
