Coordination Complexes of the Mercuric Ion with Cyclohexene Citation Hepner, Franklin Ross (1939) Coordination Complexes of the Mercuric Ion with Cyclohexene. Master's thesis, California Institute of Technology. doi:10.7907/6x1m-2793. https://resolver.caltech.edu/CaltechTHESIS:12102024-211142242 Abstract No abstract. Item Type: Thesis (Master's thesis) Subject Keywords: (Chemistry) Degree Grantor: California Institute of Technology Division: Chemistry and Chemical Engineering Major Option: Chemistry Thesis Availability: Public (worldwide access) Research Advisor(s): Lucas, Howard J. Thesis Committee: Unknown, Unknown Defense Date: 1 January 1939 Record Number: CaltechTHESIS:12102024-211142242 Persistent URL: https://resolver.caltech.edu/CaltechTHESIS:12102024-211142242 DOI: 10.7907/6x1m-2793 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 16913 Collection: CaltechTHESIS Deposited By: Benjamin Perez Deposited On: 11 Dec 2024 00:36 Last Modified: 11 Dec 2024 00:38 Thesis Files PDF See Usage Policy. 12MB Repository Staff Only: item control page

COORDINATION COMPL.EXBS o:E' 1PHE M.1~H.CURIC ION WI TH OYCLOH:EXE!ffl Thesis by Franklin R. Hepner In :Partial i?ulfillment of tne 1tequ1.rements tor t.b.e Degree of M.aste.r.- o.f so1enee California Institute of Tsohnology J?asad&na. California 1939 Table of Contents Int roduatioll ••••••••••••••····••••••••••••••••••••••••• 1 List of Notations ••••••••••••••••••.••• , ••••••••••••••• 3 Experimental : :;ection and E.rese nt a tion of Da t a ••• • •••• •• 4 Mate.ri als ............................................. 4 Analysis f .Jt' Cycl o.he~:;;ene. • •••••••••••••• ,. • • •••• • • 5 The Di s tr1 1H1•~i 0n. Mott..od., .......... • •••••••••••••••• 6 Di a t .t~ib aJ ioua a t Low /1.o h 'i Conoe ntr~tt ion OV-Jr .riixte.ndcd l:e:.c ! ods of :C ime. • • •• • •. • ••• • .10 .:r\ U° t L:t Cl' .;;t :.1U.y of tha Se co r~d.a r y Re aotion •• • ••• • .. • •• 13 Gor.irile:x .F c.r 1nB ';;l on Between 1,~e:vc urio Ion an d C;;ralohexer1e • •. • •••• • •••• " •••••• 17 Disoussion of J)a t L. •••••••••••••• " •••• • • • • ••• • •••••••• • . 20 Trea t ment I .. •••••••••••••••••• • •••••••••o•••••••••20 Treatnient II•••••••••••••••••••••••••••••••••••••• 2l Suilllna:l:'y. ·• ••••••••••• • ••••••••••••• • •••••• • •. •·•••• , • .; • • • • 25 References ••••••••• • ••••••••••.••••••••••••• • •• • •••••• ,, 2,.v Coordination Complexes of t.he i\\Iercuric Ion wi. th Cyol.o hexene Unsaturated aompoun ds Jaa ve the property of forming a class of comp ounds o:f r elat ively low stability . ':l:heae ai"e addition or eoor-dina tion a.om.pounds and a.re distinctly o.ifferent from tlle stable compounds .form.eel by addition of' halogens 01~ hydroh.aloge ns . Ooordina ti on eo:-:i.plexes of silver i on with unsa t urn ted oompoimd.s .ha ve been studied reoently. {l) The roaoti on of olefins and silver salts was .t•apid and r eversible so that 1 t -was possiol e t o study it by the d1stri1:mtio:n met llorl. Silver nitrate was shown to form three types of coordination comple xes with ethylene oom:pounds; viz: eom.binations of one silver ion vdth one unsat ura't et'i compound, two sil.ver ions with one unsatur- ated comp ound. and one silver ion with two unsa tura t ea. compounds. T.he formation of aom:pounds from mercu.ry sal.ts and olefins has been very extensively studied. Hofmann and 2 Sand. ( ) showed that ethylene combined with mercuric s a lts in aqueo.us solutions to yi.eld a compound which they designa ted by the :formula CH2 0J:l•CFl2-11gx . or by a second formu.la • CzIL1, ·•Hg ( OH) X,, which represents an intermediate ao.di ti on produot of a molecule of ethylene a nd e. molecule of a b as ic mercuric salt. trianchot {3 ) ela.irn.ed that these were merely molecular addition com.pounds a nd do not correspond to any struotural formula. Othe.r investigat ors (4} {2 } ha ve s h own since th a t cte :- ini te mercnr y-e g_ x•bon bonds exist in these addition compounc.1 .s, thus apparently disproving Llanchot 1 s theory of molecular corn.p ounae. The poss ibility the t both cm:u:plexes o.f tlrn silver type also stable [U 1c1 addition compotmd.s could. exist;, and that the equilibrium be t ween these two tyr:es of oompoumls expla ins the n ass of rJOl.nl)lio at ea. ci.ata c1oes n ot seam to h a ve occn.1.rred to i n vestiga tors hefore .. In this l gbo1..atory Lucas and >;ber~ ( 5 ) fot1nd tL.i'!.t isob ut ene h.yd.r a tf!d only ps1 rtially in the presem1e of rn.e.r- curio nitrate. That is, the oorn.plexed isobutene would not hydrate, hnt coul d still be determined by analysis. From this it seem.ed possible that merou.ry complexes analo.- gous to silver complexes are formed .. In this tllesis is reported a rese arch whi.c h has shown tl1a t mercuric ion ana_ c.1,rclohexene do :form a complex analog ous to tha t g iven by silver io! l and the equilibrium aona·tant for its for- mation h2.s been determi ned. In the research which forms ·the basis for this report there has been no attempt to isolate a oompou.nd and analyze it as t'i one by other investigators of meroury conple1G::s. but the nature of the oorn1Jound was stua,ied ohiefl.y by the distribution method :previously used_ by other investigators in this laboratory. ( 6) For what :follows it will be convenient to r.a.ention (3) here t.he not a tions whie h ere used in recordi ng da t a an d calculations. r hese notat ions conform with those used 1 previously in the laborat ory. B {Bt) = rrotal concentration of oyelohexene in aqueous phase in mols per lite1.... : Conoentra.t ion o.f uncomplexed oyolohe:xene ln ag,11eons phase in mols per liter. - Gon0.ent.ration of eyelohexene in carbon tetrachloride in mol.a per lite·r,.. -• Cono.ent.t"ation of tin-eomplexed rnerourie ion in aqueous phase in ntol.s per liter. (Hgt) = Tetal concentration of mer·c ury in a,iu.eou.s phase in mols per liter.• :. (Bl.rs/ V (:B) : Distribution r a tio of eyolo• hexane bet ween aarbon .tetraehloride and l !-I potassium nitrate. = Concentrati on of the speeies B•~g -t ... in the aqueous ph:i se in mol.s per liter. (Hg• o:n •B+) = Conoentra tion of the speaies Hg•·oli.. BT in the aqueous phase in moJ..s per liter. : Cono·e n.t :ration of added aeid in mole per liter. : Concentration of total acid in the aqueous phase in mols :per lite1'• (4) = =• (Bt) nn 0 [Ulgt }- (ht )J = eonstant recorded . ftBt )- (BJni!.lll__ with negl. igible ( B) c [(Hgt}:.lB"t'T+tB) c /KD] error. Eree~im.e~ta l Seotion and 1}"e sent at,ion o:r Data •. Materials•- In all eaae,s the inorganic ohe:m.ioals were of the C.l?. or Reagent grade. Tlle broma te-b1~omide solution was r:1ade up by weight and usecl as a standard. The sodium thiosuJ.fate solution was prepared and standardi zed ngainst the bromat e-bromide aolu.tion. A stock soluti.on of mercur ic nitrat e was ro.a dti by dissoiving a: weighed. amount of .re.i!gent graa.e o,rystals in water , adding a known r.m10unt of nitric a oid. ju.at suffiaient to redissolve the bas in salts whi c.h had preci1:iit a ted. and then making up to volume. This was titrated with sta ndard pot ass imu thioeyar1ate and. then diluted until the ionic strength of the solution was~ • Carbon te trachlorid e was purified by passi ng in chlorine, allowing the s olu•tion t o remain in eunlig l1t for a time,, removing the chlorine with sodium ll.yd.r·oxide solution, drying with caloiui:n chloride and distil.l ing. Blanks on tb.e c a rbon te t rachlori c1.e showed that i t neither used u:p nor liberated bromine 0 1., iocline. Cyelohexene wa s prepared. by the dehydrat ion o:f eyclohexanol v.ri th sulfuric a ci d . I t was purifiea. by a,istilling, drying ov<er sodiwn at le~~st over .night. and redlstilling over sodium in an atm.ospliore of nitrogen. Solutions o:f {5} cyclohe:xene in carbon t e trFJ.chloride wer.e m.Hde by wei gh ing oyclohexene i.rito a voltunetric flask a nd filling the flask with carbon tetrac hloride to volume. To test for freedom from peroxide -a , the eyol ohexene or 1 ts solution was shaken w:i.th aold-pota ssium iodide-starch solution. . ~~J ts,is, J:or ,C,vclJ>hexene,.- 1 fh-e analysis of the o-yclohexene was oe.rried. out by b:rom.in&tion with standard bromate-bromide solution. t he technique previously de- scribed (?) for cyolohexe ne was a.lightly mod.ified. Bro- nw.te-brorrlid.e solution was put in a titration .flask and the flask evacuatect. 5 ml. of 6 1~ sulfuric. acid were added and the flask wa s all owe a. to stand five minutes or more for the liberation o.f bro ni.n-e. black Gloth t-0 'rhe flask was wrapped in lower the mnount of bromine substitution catalyzed by ligtit. In the analysis of the earbon tetra- ohloride phase 5 ml. of me rourio ni -t rate solution we.re added to the flask. None WijS added to the water phase, so that eondition.s woul(i be comparable for the t1nalysis of each phase. The sample was run in and. the flask shaken for one minute. 10 ml. of 2 N socliurn chloride solution were ad.a.ea to break. a mercury-bromine complex,. Shaking .....~ ,o..,.;.,..,eJ foY bve.. m;-n11.te.s, a.Fte.Y 1V}11c~ timP-Jo.,.,f. of 2.111 f 01 ~sr,1~m i•JiJe. sol.. ~in, were . a.JJe.d 4,-,,J sJ.a./(i719 was continued. for ,'·,one or two minutes_, The vacuum was broken and the contents of the flask were titrated wi th sodium thiosulfa.te solut. ion t.o the starch•iodine end point.. 1H ve minutes or more were .found necessary for the liberation of bromine.. It is thought that mercury (6) inhibited the liberation of bromine, thus giving rise to this time requirement. Shaking was necessary after ad- ding the sodium chloride and before adding potassium iodide because brominatt on was not eompleted with tti.e mercury•bromine complex unbroken. The exoe.a s o:f brom.a te- bronlide could be varied from fifteen to sixty five per oent without introducing a n error greater than t 0.5 per oent itl the a11alysis of cyolohexene. Varying the t im.e of shaking after adding sodium chloride solution from five to eleven !llinutes tfil?tde only tO.l per cent error (twenty per cent excess bromate-bromide was used). The amount of sodium chloride had to be sufficient to form a ohloride with all the meroury present. The Distribution Method.- "The procedure consists in distributing the orga nic compound ~yelohexen~ between carbon tetraohlori ~1e and l N potassium nitrate, and then oombining the resulting distribution ratio with the other data obtained by c"iistributing the same unsaturated compound \2yclohexen~ between oarbon tetraohloride ••• it (J.) and a solution,. whose tot al ionio strength is¥• of mercurio nitrate, nitrio aoid and potassium nitrate. l'he 1 data needed are the eonoentrations of oyelohe:xene in the tw·o p.tiases, the concentration of the mercuric salt, ancl of the nitrio acid in the aqueous phase •. The prooedure fol.l owed for the distributions of cyolohe:x:ene between earbon t e tracllloride and the mercuric nitrate solution was essentially the same as tr.. a.'t used in the silver work.{l) It was found that shaking tlle (7) mixture with air caused th e cyolohexene to absorb oxy.. gen, which resulted in errors in the analysis. ·:rne re- turning of the blue starch-iodine eolor in the titration solution was oonsidered H S an indic ed; ion that peroxide was present. In several cases the oolor would return almost as fast a-s sodium thiosulfate oould be addea. in a titration. This di.fflculty was overeorae by replacing the atmosphere o:f air above the solutions by an atmosphere of ni troge.n.. Shaking the flasks in the thermostat proved irregular and inoonvenient • so meraury sealed stirrers were u.sed for tho mixing of the two phases. tl1ua g i vi.ng more uniform and thorou.f;h agitation. The meohanioal stirring made duplieation of resul.ts possible for the same stirr·in._'s times. distributions. A two neok flask was used for 'Fhrough one was plaeed the mechanical stirrer and in the other was inserted a two hole rubber stopper.. Through one hole in the stopper was a tube with a two way stopeook, am through the aeoond hole was a piece of glass tubing o:f ten mm. inside diameter over the outside ena. of whioh was a pieoe of rubber tube fitted with a screw clamp. See Figure l. Carbon tetraehloride and mereurie nitrate solution were put in the flask and the whole ring stand with the :flask,. stil'\rer. and motor wa s put into the ,..,,ater tber• mostat which was kept at 250 -to.oz0 • rrhe air above the liquids in the flask was displaced by nitrogen. After allowing the contents of t;he f'la.sk to oome to the tem- Figure I. I I / I t Fiqure Z. (8) peratures of the thermost a t the eyolohexene was added in the form of a aertain volume o:f concentrated solution in earbon tetraohloride. tube 111 It was added t hrough the large the rubber stopper while nitrogen was flowing through to prevent the posslbili ty of any air e.nter-ing. The oontents o.f the flask were stirred for a certain time and then allowed to stand until the phases separated quite alearly. S~"llpling was o.one in the f'ollowi.ng ma.rmer: A small amount of nitrogen was allowed to flow through the stopooak out the open tube. As the sorew clamp was opened the stopoook was turned so that nitrogen was flowing into the flask. A sampling pipet (Figure 2} was inser• tad through the large tube and into the phase to be sampled. A ring of rubber tubing on the pipet was pushed against the tubing on the stopper to prevent the escape of nitrogen. Thia forced the liquid up into the pipet. V'lhen it was filled the stopoock on the pipet was turned and the pipet removed. The tip of the pipet was attaohed to the evaeuated titration flask and. the aontenta washed into the flask with carbon tetrachloride or water,, depending upon the phase of the sample taken. The sample was foroed up into tube .A a.nd the wash liquid put in funnel B. pipet was oalibrated to contain, up to the sto:poook .• Before distributions were made a small amount of 1'he (9) ayolohexene wa s dissolved in merolU'ie nitrate solution and samples of this solution were analysed over a period. of several hours. The c oncentra tion of cyelohexene re- mained eonst an·t, which s liowed tha t there was no hydra• tion in the presence of merourio ion. It was pos s ible however tha t hydration of eyolohexene was taking place, but the oyolohexanol formed might use up the same amount of bromine as oyolollexene. Cyclohexanol was purified by- washing with sodium hydroxide solution to remove phenol. washing with wa ter~ wa sh ing with dilute .hydrochlorio aeidt dryi ng with pot a s•s ium carbonate and distilling. rrhe purif'ied cyclohexa nol was taken as the con stant boil- ing frac t ion a t u;go (161.5° oorreeted) !vl.P. 22°c. This puri:fied oyolohe:x:anol was di s solved in carbon tetra.chloride and it used no bromine. A wa ter s.o lu.tion of ay- olohexanol also used no bromine. In order for the distribution method to be valid it was necessary tha t none of the meroury appe ared in the carbon tetra chloride pha se.. To test t his 50 ml.. of earbon tetrHehloride pha s e were evapora ted. just to dryness in a small eva porating dish over a very low flame. One ml. of 6 U nitrio aci d wa s was hed around a nd warmed in the dish to take up any residue which m.a.y have remained (none was visible}. This aolution was diluted with 1 ml. of wa ter and divided into tw·o parts w.tlioh ware placed in two test t ubes. One ml. of a satura ted solution of hydrogen sul f ide in wa ter was added to each of the tubes. ;r here was a very sli gh t dar kening show- (lO) ing t h e possibility o:f mercury. Known aoltuions of mer- cury were tested to se.e the .e xtent of da rkening under sirnila r air crn.mst ancH,s. With 0.-00024 mi.lliequi valents of mercuric: nitra te in one ml. of 3 N nitrie acid t he hydrog en s ulfi de solution ga ve a very s i milar da rken ing . Any l ar g er a mounts o.f mercury gave darker colors and preoipita tes. From this it waa oonoluded t ha t there is less than 0 ..00001 millie q~i valents of mercury per ml .• in the carbon tetrachlor ide. This s mall amount could be fr om clissolved wa ter in the c a rbon tetra ohloride, but for purposes of the eq_u.ilibri.um measurements there wa s a negligible quantity of meroury in the carbon tetraohlo.r ide :phase. Distribut~,ons at Low Aeid CqnoentE~tiop o;Y,jJJ! !Jctended P,!_rJods of TJ.,m~•- In a 500 ml. two neok flask 100 ml.. of 0.1907 F . mercurio n:ttra te solution and 300 ml. of c a rbon tetrachloride solution O.0492 formal in oyclohexene were stirred f or 25 minutes. The phases were allowed to se para te f or 35 minutes and t wo samples of each phase were t ake n o. nd analysed. After t he samples were t aken the solutions were stirred again for 5 minutes. allowed to settle ana two more s amples of each phase a nalysed. This was cont i n ued until t here we.re no mo.re solutions remaining in t i1e fl a sk. noted about this set of da ta. f here were several things 1 The concentration of cyclo- hexene was decre asing in the water pl1a se and incre asing in the c arbon te tra ehlor i de phase, whioh sh ould not be (11) t he oasa unless an equilihri uril ha d 1Jetn1 r e ac hed a nd a i n i ti qlly in t.h.e c ar'b on t d ;raehl or il't e ,, Also t he e ons tan ts oaleula tea. were decre a si ng 'Wi t h t ime . O! a ble I and ?lot 1.) Several rans 1ive.re made v.s.rying tb.e time of s t irring,.. The 1, hne recw:r. de d was t ha t from 'th e s tat•t until t he stir• re.r was s 1;opp eo, before ea e ll sample '1,-;12s t:?. kon. 'rhis i.nela- ded th e time allowed for t ho sepa r -a t ion of pha ses n ee ess ary f or the a.h ntra etion o~ a ll pr e o ftding s ampl es. 1:he 1 times wer e recorded. thus , beoauae if tll~re were a roac1; ion proc e edi ng i n t h e wa t er phase• i t would c ontinue wh i le tha re vm s no agit a t ion, but no dis tr ibut ion wo11ld t ake pl aoe.. J?urthermore, redistribu t ion would be per- m.ittet1. 'by t h e sub [~equent stirring. One ru.n was made with s ti r ring for only five minutes at the s tart, but equilibrium a1-1p a:r en tly ha d n ot been reac l1ecl, beca us e the cons !iant wa.s low (11 .• 25) • a n d on further stirx•ing (five min- utes-, after six or seven mim1tes sta ndi.r.ig ) the cyelohexene we nt fr -o m the 0-.s.: \ rbon tet rachlori•i e into the '1tater phase giving higher oonat a nts (25.05,. then 4-8.8-, 61.0 and finally 63.D)• Twenty minutes of stirring waste.ken to be about the mi n i mum time for equilibr it1.t11 to be est ablish-ea.. Several dete:emi ns.tions, incUc a ted by ;:fin Table I and in Plot i. were ma de in s maller fl asks with only one a nalysis per flask. thus eliminati ng errors du.e to tim.ei of standi ng without stir1~i n ; . (12) Table r = 0.1907 ]' Time Change of. K./Kf at 25° Wi t-h (H.g t} (HNo3 o .osrno F .J1= 1 = f ' Time - -,' - · Cono 'n. of Cffelohexene in 'CCl H:~) 0 1 ... H.zO!Bt) . -,-~ 2tl min. ' o.Ol6l ,,,..._.............,_,__ 0.1038 o,' l hr• 16 min. ' 0t..Q..l61 ,.' -,2 hr. 30 nµn. 'i .0.0,l.6.,6 0.1028 --, .. 0.0169 ' ' ,·' . - ;I~ ' j,i !II,. : t ) tr , K/Ku f f ' •• J jpp • 66.0 ,. ' . 74.6 . ·• . • '• t 74.0 67.o 64.7 0.0172 0 .,09''74: 60.'7 0.0175 0.0971 59.z A,' 8 hr. 25 min.' 0.017s 0.0962 57.2 'll hr. 45 min.' o.01s1 0.09.6 1 66.2 ' f ' ;_p ._. iO min•' o.01a3 1:1~•. p,Q h,r,. ---, ' P'l5 hr. --, ' 55,4 o.01a4 o.0987 ' 68.4 0.0192 0.0977 f 54 ♦ 7 ' ' 0,0165 f 53.4 f o.:i.,032 ' 0.01~4 ff,24 hr. t o.Ol88 / 1 I , l hr. ' ' 0.0960 -, 20 hr. 0,0lQ3 0,0966 'r ' ' 'I ' . ' p· I WO . ..... ' ' • 71.0 0.1004 ' 5 h.r. • f 68.o 0.1005 ' 4 hr. .4 74.4 ' 2 h.r. 24 min•' ' 0.0165 ' -, '3 hr. 06 min. ' 0,0173 t ' 72.7 0.1005 ....... -_ ',. ' ·, . 20 nun. ' 0.015'; ... . ·r- ' o_.1033 ·-r 56 min. ' o,o.J.:58. .,.......,__ ' .0.102s I 0.1017 a,~ ' l hr. 40 min. ' 0.0161 3 hr. 33 min. ' 0.1010 I .... ,, ' ' ' ' ' ' ' ' f ' ' ' ' J ' ' 54a6 ' -. -··· - --,' 72.5 ' • (1 3 ) As a result of' these figures it was thought that oyelohe.xene formed a complex quite rap idly wi tll merou.rio utes of stir1"ing. At same time. and later there is a ti1e seeondary .reaction whioh is much slower. as indiaatod by the decrease in the v~lue of the constant .. tion probably is not reversible. '1\he ti.. end The reac- of the oonoen- trations of eyclohexene in tlle water ptia se f.rom. 0.1083 n1ol per lit.e r to O.0960 mol per liter and the trend of concentrations in carbon tetrachloride from o.0161 n:ol per liter to 0.0183 mol par liter indicate apparently tb.a 't the cone on ·tra tions ar e approaching values which would result from a stable comp ound. of t wo mero111;,y ions with one molecule of ayelohexene; na1tiely 0.0953 m.ol per liter in the wa·ter pb.as-e and. 0.0174 mol per liter in the carbon tetraohloride pb.a-ae •. Further Study of t .rrn Secondary Reaction.SI... . - l"I . , ' h. • Gompounds f o.t•med between olefins and. merom•io aoeta te in al.eohol solution can he titrate d witll ;potas::'i iuru. thiocyanate. {4 e) Eaoh m:aro.ury compound of t his type reacts with one equi• Valent of thiocyanate ins tead o.f with two, as merouria ion does. \Htn this in mind a sample of the water phase of OJle of the distributions was ti t1.•a ted with potassium tiliocyanate. 'l' her·e was a lower a--nount of ma1...curie ion -a hown by t itration th an was present at the s·tart o:f the distribution-. (14) The following experiment was undertaken to follow tlle aonoentration of me1.. cury in the presenoe of oyclo- he:x:ene over a period of ti.me. Two ml. of c,yelohexene were dissolve o. in 100 ml. of 0.286 formal mercuric nitrate. solution. (The oyalohexene dissolved oompletely and gave a clear solution.} The air above the liquid~ was displaced with 11i trogen a nd. the flask was shalt.en vigoously for several seaonds. 10 ml. samples were with- drawn from time to time :~na. titrated with potassium thiooyana te solution... The results are shown in Table II. Table II Time Effeot of Oyolohexene on A:ppa1"ent Jiiercuric Ion Concentration Time ' ' ' ml. of' 0 .1090 N t t KSC.I:i used per 10 ml.. s ample ' (~} ' t6Jt t ' ' ' apparent ' Cor. rected, for Hg(' ' {Hg++) ' (Hj+ +j • (Hg-i-J' o min. ' 52.47 ' o.-286 ' 6.286 Q.ooo Ca.'' -------------------r--··- --,-----,--·--~, 50.86 ,' • .2775 '' u2690 ~0085 '' 1 35 min. t 48.39 1 hr • .3i::...E£.i .n • 1 45 •.38 t .24 '7:t_........ :--·2_0_7_6_•--.-;.........._•.....~·-· _~ ...9__6_____ : 3 hr. 15 min. ' 4;2.31 f .2305 4 hr. 47 min. ' 40.89 11 hr. 10 _min. ' 3?.29 13 hr .. ~O min. ' 37.05 1" .2640 •.2230 ' el75Q ' l ' .1600 ' .Q.1530 ' .1206 ' .0827 ' .1180 ' «Of?40 n ' (a) These a re for titratLm of merourie nitrate solution wi thou.t cyclohexene and .t,ia ve not been corrected for volume o:t added oyolohexene. Correeted values would b-e 51.,44 ml. and 0.2804 rnol per liter. (b) Assuming Hg +T only reacts with thiocyanate .. (a) lig = 0.286 ming;s subsequent values. .-.0220 't t 1 f .2020 • .2420 ' ' (15) The mixture of cyolohe.xene in mercuric nitrate solution had. a very f'oul odor and oaused headaches. The1·e was no odor of oyclohexene. W'hen this was ti tra- tea with potassium thiocyanat e the sweet odor of eyolo- hexene developed. In tha last few samples when drops of potassium thiocyanate were added,, th.a-re was a dark preeipi tate formed which became lighter a s the tit.r ation wa~ continued. The last titration mixture re1n.a ined dark and the end point was very diffioult to see. A similtu" experime nt was performed with 0.-1232 mol per liter of cyclohexe-.n e in O.286 formal merourio nitrate. In this case the samp1.e·s were taken an.a. analysed for oyelohexene by bromina t ion. ir here waa an apparent in' orease in oyclohexene oonc·e ntration vJhieh is unexplainable. The samples analysed for mercury at the s ame time showed the tendency of meroury to decrease as before. The l a st titration mixture gave no definite end point. (16) Ta.'ble III Ti me Ef:feot on Apparent Conc entra tions of Cyolohex~ne and Ma:rou.rio Ion in Wa ter Solution at 25° • Time l ' f 34 min~ ' 0.1 23G f min. f 0.1228 1 f 0-.1275 ' o.2497 1 0.1330 t o. ~330 hr. 31 3 hr. 4 hr,.. • o.• 286 # ---, o•.2684 ' Q.. 1232* 0 rnin. 3 rain. 9 hr .• 17 !!':.in.. ' 0.1530 16 hr. 50 min... ' 0-.1728 f ' f 0~2100 l ' ' f '., f. I- Q~.2246 ' t 0.2537 t * .A weighed amount of cyelohe:xene was dissolved in the solution to give this value. # This value not oorreote d. for volume of added oyolohexene. The apparent inorease of o yelohe.xene and the ap-, parent deoreaae of m.eraurio nitr.!lte indicated more oonclusively that a more oomplicatecl reaction of mercuric ion and e-ycl.ohexene was taki.ng plaee-. This secondary reaotion had very little .s imilarity to the silver eoordination complexes wi t h unsaturated oompounds • .Beoa11se the primary reaction, which was apparently quite rapid. was like that of silver ion, and because the original purpose of this researc h wa s to study the similarities of mercuric ion eomplexes to the silver ion oom.plexes. attention was foeu.sed on the primary re aotion., whioh could be studied even t h ough there wer-e a seeondary reaction.• (17) ?om;plex ]'or:ma.tion Be. .t ween Merolll"io Ion and Cyolo,,., 4 h(3.:xene.- The calculated constants K/KD at the shorter times were considered to be due almost entirely to the primary reaction. These constants- were used to study the reaotion and were obtained in the following manner. Three distriba.tions were made for each ooneentrati0-n with stirring one b.alf hour, one hour• and on.e and one half hours respeotively. 'l1he constants K/KD oaloulated for these three runs were extrapolated to zero ti.me. The oaloula ted coos.tants were not the same for different oonoentrations of merau.ric nitrate. The more dilute solutions of me.rcurio nitrate were prepared by diluting the stook sol11tion with 1 N potassium nitrate to keep the ionic stre-ngth at,.,«• In this way the acid was also being diluted and the effect might have been due to aoid concentration. A series of determinations was made at one concentration of mercnrie nitrate but with different acid concentrations. The oalculated eonstant changed as shown in Table IV. A.t the higher acid eonoentrations there was no drift of the eonstant with time o:f stirring,. but a t the lower acid conoentrations tile drift was the same as indieated in Plot 1, a decrease with time. ., - 'i 41.6' i hr. ,----, ,tl.4' t ' 40.6 ' 41.2' -, ' ' ' . ' 4{:,-.()r 0 .. 1907 '0.21756 '0.,01001 '0.0606 ' ·~ o • i11 • • • 1 t,,., .,, ... , 25.8' 46 • .3 J 44.5' 42 •.2' ·y 46afi --,.......,.._,,>M> , . • 11111p.11 .1a 4 f · · , ., r 45.-9 45.-5 ' 42.4 ---,.' 85.6 ' I • • • ,..._ 47.,4 ' · 1 r r t b r -•___..., 47.7 1 • 46 .. :8 ' •~ -~~ r ' ~ -•- 76, . ... 0 ''· f' · ,_.- SGtzJ.r .... C 20.3 , ,. ' . --:r 46.5 ~ ~ _ . , . . _ .,.,_.,'°' Ulf S,_ • • - •·t~"' I *, ~iit:rl- ues t••J_,fi;,'en Lrofil ·u t ..,1 -:-.·1 ot · • l • t;> e- 1·. and. ..r: ~ - . . . . . . , . _ _ . . . . ~ ---~ , 1 1l __olla4 .' · • ~ ' 1 ... r · - · • ' 79.5 ' - ' 42.5' 21 i:n,•. . y-----,.,...-- · · -- ~-r-. - - 1 0.1907 0.0158 '0.1040 ' ~--~-~..,'0.0980 . (. . ._,,.------_,,.......-----i ~ "-- .__,.,. ""' 24,.,9, - -· 1 o• •.o9 5~t , 0.5490 0.0252 •'0.-037-6 , • • ---r--......,._.,._:- . . - - - ~•..,....__,,._... ,12.4 t 45,.Q t -- T l 0 -.0954 'Q.274O f(} .00364 '0~0137 0 ...2740 ,'0 •.0209---~.,..-'0.0449 8 ~~-6' .....,__, 45 .6' 1 ·--v r 0.0954 '0.2740 ?0;4!00805 ,_ '0.0256' 0.0954 ,. 0.0954 '0 -. 0963 !Q.Olg3 1 0.0529 ---·- I I I.~ '0.0558 ' 108,it~'- 105.• --8' 103.2 ' ................ ~":,.,......,...........,' I -· - f 0.0954 '0.0490 'O.Ol~'-35 ' --F:;f i(r; . ---,---·--,. l hr. l l hr. Ex t.rap•' 'O .02'71 ' ' f r- 0 .0477 '0 .2731 •0 .• 0 :329 {Hgt) r,,·- Ei:tra1>~1ated (B) 0 (Et) ' (B.N0'7)) , .., ,...._,.,,.,, Values of l~ /K"'.u Olltained by Distribu t ion at 25° of Cyelob.exene Se-tween uc4 and Hg( J'W 3} 2 + B.11O3 -r Kl\1O3 1~q. a t y. Table IV co - I-' .--, (1 9 } From this it was seen Ghc:: ti ctuicl affected tl1a constant. so :plI 1'0-<'Hl ing s were ma de \.vi th a Eeokmar.w pH meter to see if hydrogen ion wa s f'orm.ed w h :Jll oyalohaxene was disso.l ved in mero i1rio nit.rate. Headings v1ere t aken on a merouric nitrate solu.•t ion, then. the solution was saturated with oyclohexene Gi.ml readings a gai n taken. Table V sholl'lS Change of pH of Mercurio rq1 tra te Solutions Jben Cyelo-he~ene was Added . pE of Marourio 'pH Immediately after' • ;.~e ~o " l m;, ion . .,• N1• Tirf~ / d" ~ ,, J..'l-lO T.' c:.1• ti. on o..i. 1J 6 .i1. 'f pH af'ter '' t ~ npprox, . o~J. h ours ·t f t ' l.55 ' 1.-16 1 l.04 ' 1.zo ' 1,. 07 • o.• 77 t 1 . 19 ' 0 . 92 o.77 {a} ' (a) l!wo hours for this value .. ll'rom thts it waa evident that hydrogen ion was f'orme d. In order to make oaleula tions of this effe-et 1 t was necessary to know the exact concentrations in the mercuric nitra te- solutions. The- aeid in the stook solution of' mereurie nitrate was determined by preoipitatin.g the mer... oury with hydrogen sulfide,. filtering and washing the preeipitate ., boiling the filt ra te and washings to remove the exoess hydr-og'6n sul.fide • an d titrating the total acid with standard sodium hydroxi(le. Sine-e tne concentration of mercuric nitrate was lcnow~1. , the amount of add_e d acid• wh1oh was the s um of the amount actually af.ded and that originally in the mercur!~ nitrate, c ould be oalculated. (20) Table IV also i nclml es result s f ro;:-) varylrl{; the oom-;,entra tiorw of mei·euric. ni.tra t e, cyclohexene and. a cic1. J)is.ou.ssi on of the Data .rreatment I.- Sinoe acid. oonoentration has stteh a 1 l~n~ge ef:fec t on K/K,. . and si nee it ha.a heen shown tha t ·"' d.i ss ol vi ng oyclohexene in mere i.:tt·ic nitrate solution liberatt1s a cid• e quation I suggests itself for the reaotion }i.c, ++ -t- B -0 + H2-0· ~<""" " A " ... •B·•Off+- t- H+ ~"'6 (i} taking plaoe wben oyolohexene and mercuric ion f'o1"m a complex. The equilibrium eonsta.ut foi: the reaot.ion re- presented by equation I is given in equation II. { II) I:f we <le.fine K0 aa K1/Kn tben K0 is given by equation III if e quation I represents the true state of affairs. (III). (H ) in this treatment is given by equation IV. This treatment seems to fit the data qu.i te satisfactorily. (IV) The values for K0 given by equa t;ions III a nd IV are listed in Table VI .• (21) Values of K0 Obtained by Using :Equa tion I ! (Bt) +(Hrio3 ) R'. 0 •K/Jt . .,. , J) (B+) ' (Bt) ft K/K; UfM03 J 't .(H"'T= ' Ei.qaa t.lOll · J.~-~r ' ' ' 'f I . '111.z"" /1.7 ' t 0.0954'0.0135 '0.0558 1 H-G.. 1 0 •.0490''' 0.1048 l:i:~5 ' l ' t .0954 1 ..-0 153 ' • 0!)29' 85.6 1 .09i;3 1 •.1492 12.a. ' {I-fit)' {B)a 1 . !I ' .0954' .. 0209 t .0449' 42.4' . 2740' ' i f ·-,· ' .0954' .00304' .• Ol3Y' 45.9' . 2740' - .0954 t .00805' .0256' 45 .5t .2740' . -- •.0954' .:0252 .., f iat .1907'' .Ol.58 .0376' 25.7' .5490' ' .1040 t -f 1 f i 76.QT .0980' .3189 . . ' 13.5 .2~96 . 2877 .047'7' .0320 t .0271' 41.2' .2731' lJ.O ' l.5 •.1 .5866 .2020 ' l ' .1907• .01001 ' .0606' 46.t:l' .2756' 13.5 15..4 1 ' ' ' ' ' t ' ' 15.? .3362 f .3002 1 2 .4 Mean Devia.tionz 1. 2 These values vary from 11 •.5 to 15.7. the me a n being 13 •.7 and the mean deviation being :t 1.2. When sil.v er nitrijte forms complexes with oyalohexene there is no ac id libera ted. (l} Even though mer eury s alts like to hydrolyze, it seems probable tha t there is a complex formed similar to t he silver oyolohexene oompibex and represented by equation V. With the assumption of two eomplexes the da t aare better correla ted tha n by tre atment I (Ta ble VI). 1 f Mean-13.7 Treatment II.• ' Assuming both reactions represented by equations I and V and ' t t (22) defining K ' 0• K =Kf K ' \K - depends on hydrogen ion ooneentra .. D D tion a s s hown by equation VI. K~ ) . K/K D :: Ko' ·I {H VI Usi ng the series of' runs with (ilgt) : 0 .. 0954 a first approxima tion to K~ ws,s obtained by plotting K/KD against l 1R"11 using corrected (H+) from Table VI. pro.x imation wa s five. The first ap- 1lhen this value of Ko was used to obtain a better approximation to the hydrog en ion eonoentra tion ·with the rela tion show.n in equ at ion VII. {H+) : K/K •K' (HN03) + (Bt) X ( K ~ ( Vll) K/ KD agijinst the better correatad (H+) is shown in Plot 2. The va lue of K.~ from this plot is the same as the first a pproxil'ilation. Table VII shows the constanoy in K0 obtained 'tly using 14, :: 5 in com1ection with equations VI and VII. Table VII Values of K0 Obtained by ~rre a tm.e.n t II for Rans With (Hgt) = 0.0954 Meam Deviation :'" 0.3 J w (23) Thus at constant mercuric nit rat e oonoentra tion. treat- · ment of the datf.l assuming two kinds of complexes handles very well the effeot of aoid conaentra.tion. l'he low 1 value of K0 fort.he flrst run in Table VII oould be ex.. plained in this manner. It had a relativ ely low initial acid oonoentration whioh mig ht not have been exactly right due to the faot that mercuric nitrate may llyclrolyee slightly to .form more acid. A higher value for the aor• reeted ae1o. oonoentration would give a value of :&: 0 nearer to t ha t of the other runs • . With K.6 : 5, similar ealculations of K0 for other concentra tions o! merourio nitrate disol.ose a trend in K0 with concentration of· mercurio ion. as shown in Table VIII. Table VIII Variation of K0 Obtained by Treatment II With (Hgt) t i 0.0477 .5954 ' 10.6 t ----r------r1. t;" (a j ' ·•1~. '7 ~\) ~ n (a) Average of values in Table VII. (b) Average of two values 13,8 and 13.6. If it is assumed that mercuric nitrate has a different salt effect than potassium nitra te and nitric acid these results are logieal. {24) There are several reaso1:is why treatment II is better th.an treatment I,, In t.t•E>111 tme :n t I tl1e K0 var,ies 1111 th both acid oonoentrl}tion. an<.l mereu.r 1c nitrate oonoentration; while in treatment II K0 varies only witb mer<.H11?ie ni• trate eonoentra ti on. It seem.a right to assume that t~eat• ment II is corx•act becausa the drift of K0 with inereurio nitrate aonocntratim:l is similar to the dt"'ift of tile eon• stant for the silver~~yolohexene oomplex.,'1 } Also tbere ia the sin1ilar1 ty of the reactio.11, ahow11 by 0qt1ation V in tre~tment II to t.te reactio.n. of silver nitrate with 0,yalohe:xene • One oould. argae tha '.& tho d.ifferenoea in salt effects or nl trie acid,, potru:tsi.um ui t ra t~ ~u1:a.. meroar10 nifu.•t; te would oause the varia. t:iona of K0 found by treatment :r•. Rowev-e r; Luo a s end E'berz {5 } found t.r.ia t potassium n1 tI'& te 11.a s the same salt ~ffeot as nitr•io aeid upon 1sobt1te.r:uh It seema lo.gica.l tl1at tl1;i.s would also be true with othsr olef'ins a,ach as oyolohaxe.lr),e . Tliis equality of E!nlt effect is indioated. in treatment II by the constancy of K0 at a constant merourio nitri:.1te ooncentration. J.1otasslv.m. ni• trate and n1tri.G aeid must have equal salt effeGta 1f K0 remains const1:u:1t td.th variation in nitric ao1d at qonstant mercuric nitrate concentration .. (25 ) Coordination e-0.mplexes of the mer0urio ion with oyolohexene have been atud.ie <l chiefly by the distribu• ti'on of cyclohexena between earbon tetrachloride and solutions, at ionie strength of ~• containing merourio nitrate. nitrio acid and potasf! ium nit.rate. Evidence has been presented for assuming there are oom:plex ions of t wo types. viz., B.g•B•OH+, formed 1:-1000.t'o_- ing • to the equation Hg...++B+HzO ~lig•:B•on+ + H+ • and B•Hg.,_"'- • formed according to t h e equation Hg++ +B ~ B •p~ ... + • Equilibrium oonstants ha ve been oalculated for the formation o_f these complexes. 11wo methods of treating results have been considered and tr.1e superiority of one me t hod has been demonstrated on the ba sis of the probable vnlidity of the results whioh it affords. Experimental data, :f'rom v;hich it wa s deduced that a slow seoo11dary reaction waf~ proceeding oonourrently with the other two, were obtained. (26) The author is greatly indebted to Professor h . J,. Lucas for his suggesting this research and for his ad"" viee 1:u1<1 assista nce th1~oughout the course of the re• s -:J arch ana. the writing of this thesis. 1?.he helpful <H•itioism o:f. J).1•~ .'J aul Winstein in t;he 1 interpretation of the data and. the writing of this thesis is gra t;ofully aolmowlerlged.• 'rhe author wishes to expre ss his appreciation tq I1. E. Gullekson for his preparation o:t' the fig1.1res aud plots :f or this thesis. References (1 ) Winstein and Luc a s~ l . Am , Che m. Soa. 60, 836 (19 38) · ------~---- ( 2) ( a} Hofma nn and San d , Ber. 33, 1 ~140 , 2692 (1900) (b} Sand, ....._...__. Ber. 34• 1385, 29"o?r (19 01) (4) ( a } Adamso Roman and. Sperr,y , J • A.mo. ~ • ~ • 1781 (192 }3 ) (b) Sandborn and W ~r vel, ibid., 48, 1409 (l9 26 } (e) Griffith a n d M.ar vel, i bid•• ~. 789 (1931) (d) Hut;(3l a.na. Hibou, Chemi..§. tl .!Jldustrie, Speci a l NO, 296 (F eb• 1 92'} Ch en1. bJtsJ;_. ~ • 3898 (19 2 9) ( e) Wrig ht , JO Am i. Chem .. _,,....,_ 3-)(h ~7 ; 19'J4 (l\1 35) ~ ·· - ti, ; -- ~ - (6 ) Eberz, Welg a, Yost, and Luc as; J o Am. ~............,_ Che m o Soc" --59 4 5 (1937) (8) Fiberz and Luc as, 1-.• ~ Chem.. .......-Soc . ........... 56, 1 ::~ 30 (19 34) ~