The Rate of Decomposition of Ethyl Hypochlorite Citation Ellis, Emory Leon (1932) The Rate of Decomposition of Ethyl Hypochlorite. Master's thesis, California Institute of Technology. doi:10.7907/3DTD-RK20. https://resolver.caltech.edu/CaltechETD:etd-04262004-144509 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 Awards: Caltech Distinguished Alumni Award, 1970 Thesis Availability: Public (worldwide access) Research Advisor(s): Unknown, Unknown Group: Caltech Distinguished Alumni Award Thesis Committee: Unknown, Unknown Defense Date: 1932 Record Number: CaltechETD:etd-04262004-144509 Persistent URL: https://resolver.caltech.edu/CaltechETD:etd-04262004-144509 DOI: 10.7907/3DTD-RK20 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 1508 Collection: CaltechTHESIS Deposited By: Imported from ETD-db Deposited On: 29 Apr 2004 Last Modified: 06 Dec 2021 22:54 Thesis Files Preview PDF (Ellis_el_1932.pdf) - Final Version See Usage Policy. 4MB Repository Staff Only: item control page

OF THY HYPOCHLORITE Thesis by nmory Lb. Ellis In partial fulfillment of the requirements For the cegree of Lastor of Seience. California Institute of 7 echnology sadena, California 1952 Contents Tntroduction. ...csecceeee: Experimental varte......6. erevaretion of eterials. hethod of Yollowing Rete. Dataerccrce .cecvcccscese DiSCusSSion.cwccocrccccveces REACtiONS. .-r.ccccececeee Reaction Rate Constants. MeGhendi Ste sess cccccrecce Temoerature coefficient. SUMMGALY «s+ +2 seeveeseccees ReferenGeSe -cececcseseccece -l- Introduction Ethyl hypochlorite, first preceres by Jendemeyer {1) in 1885, is conveniently mede in an aoveretus like the one deseribed by him (2). The substance is highly unstable, decon- posing at room temperature. In direct sunlight the heat of decomposition is sufficient to cause vigerous boiling, soon followed by explosion of the vepors. In dilute carbontetra~ chloried solution at room temperature, ethyl hypochlorite is reletively stable, since efter tvo to three days, less than ten ver cent has decomposed. This decomposition is auto- catelytic, since after five days 80 per cent or more of the substence has disaypeared (3). No thorough study has been made of the decomposition of alkyl hypochlorites. Chettawey and Backeberg (4) report that the orimary decomposition products of elkyl hypochlorites are the corresvonding alichyles or etones, end “Cl or alkyl chlorides. These reagtions mey be resresented by the following ecustions: --oo01 — = Ry CO + NOL Rg-C-001 —— Ry-CO + R-Cl Chattawey end Beckeberg (5), investigating the chlorination of alcohol, find that ethyl hysochlorite is formed but quickly brea':s dovm in the presence of excess alcohol to give ecetaldehyde end Cl. Teylor, Veehullin and Gemmal (3) report good yields of ethyl ecetate obtained from the decomposition of ethyl hypoehlorite. The reactions vronvosed by them are the following: meer e -2— o,-080 + ¥g-0#,001 —» CH,COOC.Hs + Ha Durand and Haves (6) voint out thet chlorine is also ea »roduct of this decomposition, and suzgest the following equation for its formetion: CHazCH,-OC1 + HCL —> CHsCH OH + Clo The vresent work was undertexen with e view to determining the mechenism of the ¢ decomposition of this extremely interesting substance. Sreliminary tests showed that dilute solutions of ethyl hypochlorite (0.1 to 0.3 mols ser Liter) in dry carbon tetrachloried are cuite stable for several hours, if not for several days, at room temperature. dJhen dry Cl gas is dissolved in the carbon tetrechloride, the decomoosition takes nlace at a meesurabdle rate at 40 or 50°C. ‘The oho tochenical + reaction wes not investigated; all the work referred to in this yerer ves done in the dark, or in the presence of weak artificial light. The dete obtained in the measurement of the rate of decomposition are given in the experimentel pert, and in the diseussion vhich follows the attempt is made to victure 2 mechanism in egreement with the observed facts. Bxeoverimental Part ereparation of Materials: The ethyl hypochlorite used in these experiments was prepared by Sandemeyer's method (2) which is briefly the following. Ethyl alcohol is mixed with 50 NaOH in the proportion, 1 mol eleohol to 2 mols lea0H, end enough water is added to »roduce a clear homogeneous solution. This solution is pleced in an inelined glass tube, jacketed with ice water, and closed at its lower end by a stop-cock. ‘Then the solution has become cold, chlorine is cdmitted at a moderete rete until it is no longer rapidly absorbed. This usuelly requires 20 or 30 minutes, during which time a greenish-yellow layer of the hypochlorite collects above the aqueous phese. The chlorine current is then stopred end the a ueous phase run off through the stopcock. ‘The hypochlorite phase is caught in « separatory funnel containing ice-cold helf saturated sodium bicarbonate solution. ifter gentle agitation for a few seconds the hypochlorite »vhasge is allowed to Sink to the bottom, and is immediately draw off into an ice-cold i flask conteining a few granules of anhydrous calcium chloried. after gentle esitation for 50 or 40 seconds to remove the water that unevoidably agcompanies the hypochlorite, it is pivetted directly inte a glass stoppered flask containing the earbon tetrechloried solvent for thet run. The volatility of the substerice and temperature incertainties made it undesirable to attempt to use the volume ss an accurate measure of the anount ~4— : of material added. Titration of ea sample of the solution immediately efter mixing served to establish the initial concentration of the hypochlorite. Cerbon tetrachloride wes prevared for these runs by drying the commercial CCl, over Po05 for several hours with mechanical ‘stirring, decanting the clear liquid into a dry distilling flask end distilling. The middle portion of the distillate was stored in a glass stoppered bottle until required. Dry hydrogen chloride wes dissolved in the carbon tetra- chloride for most of the runs. It was prepared according to the conventional method, namely, by running concentrated c. Bp. hydrochloric acid into the bottom of a tall bottle containing concentrated sulfuric acid. The gas delivered from the bottle was Led through a sulfuric ecid wash bottle into the carbon tetrechloride to be used for a particular run. About 30 minutes is reguired to obtain a concentration of about 0.1 mols HCl per liter of solution. Lethod of following Rete: About 150 cece of cerbow tetrachloride wes nlaced in a FR flask connected with the HCl generator and =Cl was pessed throuch it until epproximetely the desired concentretion wes reached. this solution was kept in a glass stoppered flask during the : preparation of ethyl hypochlorite. As soon as this had been edded to the flask, the contents were thoroughly mixed. Two. LO cea. Sanples were pipetted into iodine flasks containing an excess of FI and a Imown quantity of stenderd acid. The ~5- n remainder of tne solution was pipetted into thin walled test tubes, previously dram out preparatory to sealing. In all except one run, 10 Gea. were pleced in each tube. after being sesled off, the tubes were placed in a wire rack and lowered into en oil be h which was kept at e constent temperature ‘by means of a mercury regulator. The menipuletions from the addition of the hypochlorite to the carbon tetrachloried, to the placing of the secled tubes in the thermostat requirea about fifteen minutes. Preliminary trials indicated thet the rate of decomposition et 25° is slow enough to justify the selection of the time of plecing the tubes in the thermo- stet as zero time for that run. At regular intervels one of the Semples wes withdrawn and analysed. Analyses were made according to the following proceedure. Stendard acid ‘or distilled water if the ecidity of the sample to be anelyzed was known to be sufficient) was pipetted into a 500 cea. conicel flask containing a few crystals of KI. A semple tube was them removed from the thermostat, quickly washed with alcohol, placed in the flask and broken with a glass stirring rod. The flask wes then stoppered and sheken vigerously for at least 30 seconds. This shaking is necessary to provide sufficient contact between the two phases to complete the liberation of the iodine. The iodine set free wes then titrated ‘to a starch end point with 1/10 thiosuldate solution. Then a few drops of phenolyhthalein indicator were added and tne conte” contents of the flask titreted to neutrality with standard alkali. Since hydrogen ion does not ehter into the thiosulfate -~6- reaction, this alkali titration is a measure of the excess acid in the flask after the liberation of iodine from the XI. Data: The following twelve tables summarize the data obtained from twelve runs under different conditions. The first column gives the time in minutes from the instant of placing the sealed samples in the thermostat. The uncerteinty in the time recorded (due to variation in the manipuletions, es washing, cooling, breating tube in flask, ete.) is not greater then one minute. The second colum gives the millimoles of iodine set free, computed from the thiosulfate titration. It should be noted that one mol of hypochlorite or one mol of chlorine sets free one mol of iodine: | EBtOCL + 217 + H” —» EtOH + I ” Cle + 21 ~» I, + 217 The third colum records the millimols of lla0H required to titrate the sample to neutrality following the thiosulfste titretion. One must, of course, subtract the number of milliequivelents of acid added initielly in order to obtain this value. In other words, since the Lliberetion of iodine from FI taxes place cuantitetively only in ac fe - Qu solution, and since one usuelly is required to add acid to the titration flesk before breaking the sample tube in it in order to insure sufficient acidity for this decomposition, one must subtrect this acid from the UeaOH titration to obtain the velue of the net leor. Lay “os In the first of the two equations above, hydrogen ion is T= - used up in the reaction. ‘Assuming thet ethyl hypochlorite is the only substence present in the solution which will liberate iodine (see discussion below) one must edd to this "net laoH" the number of millinoles of iodine set free (i.e. the number of millimoles of EtOC1l in the sample) in order to obtain values for the quantity of "Cl present in the sample at the time of enelysis. These velues are given in ¢olumn four, end are in effect the algebraic sum of the values in columm two end three. the data from these tables are presented granhicelly in figures 1 to 12, where the concentration of =toCl and of "Cl, expressed in mols per liter, cre plotted agseinst time. . Table Ie Gonditions of Run #1, Thermostat temperature 50°C. Volume of samples 10.00 G.Ge Time > 4llimoles I. Lilliequiv's lillimols NCL set free net lacH" in semple ae) 2.179 -0.549 1.630 re) 2.177 -0.557 1.620 45 1.661 0.567 22028 75 1.549 0.578 2127 105 1.454 0.764 £0218 155 1.401 0.872 Beeld 165 1.319 02999 20518 195 | 1.282 1.073 £0055 228 1.255 1.152 22587 285 1.160 1.257 £ed97 Table 2. “Conditions of Run #2: Tempereture of thermostat 50°d. | Volume of samples 10.05 c.ca. (to ECL addei to carbon tetrachloride) Dime Lillimols I. Lilliequiv's Lillimols HCl set free "net MaoH" in semple ) 2298 -246531 -0.053 0 20294 -24538 ~0.044 120 £2285 -2.181 0.102 560 £eB9 22519 -0 .040 1440 24260 22285 ~0.025 3020 - £24184 -22079 0.105 2410 22027 -1.735 0.292 5870 0.5385 ---= a 5900 0.4612 1.059 1.520 5920 © 0.4886 1.023 1.512 ‘Conditions of Run #3: Temperature of thermostat 50°C. | | — -Yolume of samples . 10.00 @ec. Time Lillimols Ip Lillieguiv's Lillimols HCl set free met VecH" in sample ) 1.976 ~i.264 0.712 ie) 1.967 ~1.281 0.686 30 1.255 0.187 1.440 60 1.142 0.361 1.503 90 1.094 0.406 1.500 120 1.038 0.517 1.5556 150 — 1.006 0.556 1.562 180 | 0.978 0.592 1.570 270 0.900 0.689 1.589 500 0.887 0.705 1.592 330: 0.868 0.767 1.605 360 | 0.856 0.730 1.586 o. B90 0.830 ° 0.751 1.581 -ll- Table 4. ‘Gonditions of Run 4: Temperature of thermostat 50°C. | | Volume of samples 10.00 Gece rime Lillimols I. Milliequiv's Lillimols £Cl set free met wade" in sample fe) 0.882 -0.147 0.735 0 0.895 -0.162 0.753 50 0.772 -0.069 0705 60 0.757 0.003 0.760 90 0.753 0.029 0.782 120 0.753 0.045 0.798 180 _ 0.748 0.081 0.829 240 0.724 0.110 0.834 500 0.721 0.156 0.857 360 0.709 0.159 0.868 390 0.703 0.163 0.872 420 0.699 0.180 0.879 -12- Table 5. Conditions of Run #5: Temperature of thermostat 50°C. Volume of samples 5eOC GeG- Time Lillimols I, Lailliequiv's lillimols HCl | set free net WaoQH" in sample 0 3.589 1.478 26111 O 50578 -~1.462 20116 30 1.557 0.452 1.989 50 1.471 0.463 1.934 70 1.375 0.5352 1.907 85 1.3508 01584 1.892 100 1.257 0.640 1.897 115 | | 1.286 0.649 1.935 130 1.267 0.647 1.914 145 1.200 0.689 1.889 160. 1.174 0.724 1.898 175 | 1.182 0.752 1.814 190 1.lil 0.726 1.837 205 1.138 — 0-745 1.883 ‘Conditions of Run he: | Temperature of thermostat 40°, Volume of samples 10.00 GG. Time — Millimols Is ‘ydlliequiv's Lillimols cel set free ‘net tadH" in sample fe) L971 ~0.848 1.123 15 1.721 ~0.499 222 30 1.502 -0.011L 1.491 45 1.420 0.157 1.577 60 1.404 0.208 1.612 75 1.575 0.271 1.646 110 — | 1.319 02566 1.685 140 1.290 02452 1.742 170 1.253 0.505 1.753 200 0280 0.553 1.776 L 260 © 1.168 0.646 1.814 -14- © “Conditions of Run Amy Temperature of thermostat 40°C. Volume of samples 10.00 Gece Time Lillimols I, Lilliequiv's Lillimwols HCl set free - met Nadu" in sample 0 20541 ~1.751 0.610 15 1.991 -1.465 0.526 30 20197 -1.553 0.644 45 2.058 -1.227 0.831 60 1.627 -0.297 1.330 75 1.320 0.358 1.658 90 16267 0.425 1.692 LOB mmm ee 120 1.249 0.404 1.6535 150 1.221 0.447 1.668 180 — 1.201 0.489 1.690 “Gonditions of Run “8: Temperature of thermostat 40°a. Volume of semples 10.00 cece Time lillimols I, williequiv's iillimols “C1 | set free - net LacH" in semple 0) 1.006 0.258 1.264 15 0.911 0.506 Leel? 50 0.923 0.251 L.1L74 45 0.928 0-270 1.198 75 0.920 0.211 1.131 155 0.892 0-330 L222 195 0.892 0.385 1.277 045 0.844 0.570 1.414 360 0.845 0.496 1.039 560 . O.787 0.586 1.575 Conditions of Run #9: Temperature of thermostat 40°C, Volume of semples 10.00 oc. (fo ethyl hyvochlorite added; chlorine dissolved in Col to e concentration of 0.10 mols ver liter; ethyl «leohol sdde. to a concentration of 0.20 mols per liter). Time iillimols Is Milliequiv's Millimols =o set free net Nady" in semple fe) 1.0353 0.579 1.412 15 0.910 0.405 1.515 30 0.870 0.429 1.300 45 0.881 0.512 1.393 195 0.687 0.902 1.589 225 0.624 0.995 1.617 270 0.616 1.019 1.655 285 0.605 1.047 1.650 -17- Mable 10. Conditions of Run #10: Temperature of thermostat 40°C, Volume of samples 10.00 Gece (Added ethyl alcohol to usual reaction mixture to a concentration of 0.17 moles per liter). Tne Lillimols I. Lilliequiv's ‘illimols I set free "et ifaoH" in sample 0 1.826 ~1.599 0.227 15 1.786 ~1.513 0.473 20 0.9359 --- ~=— 45 0.845 0.558 1.203 60 0-821 -—- --- 75 0.798 0.513 1.511 120 0.680 04537 1.317 135 0.649 0.671 1.520 165 . 0.591 0.756 1.547 195. 0.558 0.805 1.363 205 0.477 0.905 1.382 -18- ~ Meble ll. Conditions of Run #1l: Temperature of thermostat 40°C. Volume of semples 10.00 Gea. (No éthyl nypochlorite edded; chlorine dissolved to a coneentration of 0.181 mols per liter; ethyl alcohol sdadcd to a soneentration of 0.40 mols er Liter). Time Lillimols IT, Lillieauiv's lnillimols <C1 set free met iadH" in sample Q 1.810 O.271 2.081 LO 1.553 0.721 22254 30 1.547 1.069 20416 45 1.2453 1.255 20478 60 1.153 1.380 2.533 90 0.998 1.610 22608 120 0.884 1.764 £2648 155 0.817 1.817 2654 150 0.766 -~ _- L765 0.694 1.956 24630 Conditions of Run #12: Temperature of thermostat 40°C. ‘Volume of sarples 10.00 GeGe Mime: Lillimols I, Lilliequiv's Lillimoks 2C1 set free Tet acu" in sample 0 14598 ~0.474 1.124 15 1.552 -0.596 1.156 30 1.452 ~0.258 Lecld 45 1.349 -0.050 1.299 60 1.290 0.063 1.5538 75 1.185 -- -- 90 1.254 0.144 1.578 105 L.£77 0.L70 1.347 120 » 1.1935 0.209 1.402 165 L.1lél 03500 1.441 2LO 1.062 0.553 1.415 awit 4017 D12U2 207 = 24 “Ter erery dH ttf a mz UOLD41{U2ZIUOD a Time mi UOL{DAZUZIUCD gui f at ‘UOLLDALUBIUO aud} f ~24 - ; Ss ‘y Q = S = BuUIt Seon! 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Reccreecte 7 : i : = io as ta ae 5 tf L(t | ae i Hl i | ale 5 taht HH sedate ea ot Pre t ee ; i : Ps + F in i ee Lon ren coy C 7 7 . Ae te L- pach eT | : i : : an oan aan oe ri ‘ai - pfs “eft anne &) a ae M4 4 i_ eee VT Ta a ~ am + i 7 i { | T 7 H 4. \ I iT iti i J : | - * t 1| aa |; mani eel I | | Ll H : Discussion ‘The reections taking plece in this system are by no means epparent. Preliminary experiments at 25°C. showed that the rete of diseppearence of oxidizing substences from the carbon tetrachloride solution is more rapid in the presence of dissolved Wel. L comparison of Run #2 with say Run #1 shows this difference. The work of other investigators on dthyl hypochlorite and related substances indicste thet in mey undergo decomposition in several weyse We will consider in the following paragraphs some of the res reactions that may take place. Chattaway and Backeberg (4) have prepared e series of alkyl hypochlorites. They find that the n-propyl, i-propyl, n-butyl end i-butyl hypochlorites are very unstable, and keep only a short time even at ice temperetuvres. The tert-butyl and tert- emyl hypochlorites ere relatively stable, and cen be kept at room temperature in the dark. ‘The »oreperetion of a nypnochlorite from benzyl eleohol was attempted, but apparently the substance is so unste 5 ble thet it decomposes almost as fast as it is formed, to give benzaldehyde. The chief decomposition products of the oth. a other hypochlorites are indiceted by the following ecuaticns: & R-Cip0GL — R-CHO + ECL Ro-CHOCL —* R,-CO + HCL R.-Cocl —_ R_-CO + R-Cl Teylor, lachullin, and Germmal (5) report 80 to 90% yields of ethyl acetate, obtained from the decomposition of ethyl hypochlorite, for which ¢h OS ° ? Gh they postulate the following reactions “4. stool — _ oe + 31 Re Hg0HO * Etocl —> Etoac + Cl Durand end Naves (6) point out that ethyl hypochlorite reacts with BOL to. regenerate the alcohol end chlorine. This reaction, under the proper conditions, can be violent. 3. EtOCL + HCL —» EtOH + Oly The evidence of Chattaway and Backeberg (5) indicates that the reverse of this aetion takes plece when chlorine is passed into alcohol. YWone of the ebove reactions have been reported as taking place in a system strictly analogous to the one under considere— tion, namely, in dilute carbon tetrachloride solution. The purpose of the present paper is to set up a tentative mechanism whieh accounts in a qualitative iff not in e quantitative way for the date obtained. This mechanism will then form a convenient point of departure for additional experimentel work. In attempting to work out a mechanism aceovnting for the observeé facts, it is more satisfying to consider only those reactions 4 £1 known to take place than to set up a series of hypothetical reactions for which there is no evidence. Such a tentative mechenism is developed in the following pages. “hile its guentitative agreement leaves much to be desired, it hes the recommendstion that the deviations can to some extent be expleined, end no new hypothetical reactions had to be introduced. In ell the reactions considered above, one mol of "Cl is produce for every mol of BtOCl decomposed. Even if sreaction 3 above takes vnlece to completion, the subsecuent disanpeerance . ~34-— a of Cl, would be expected to liberate an equivalent quantity of Hol. 4 casval inspection of the tables or curves will show that this amount of SCl was seldom found. In the case of most of the runs, the discrepancy is not large enough to become of mejor importance. In the case of Run #5, where the initial BtOCl concentration is about Live times thet of most of the other runs, there is Little or no 4Cl formed in the decomposition. Apparently, to investieste the reactions by which itocCl disappears without forming ecuivale:t amounts of HCl, it will be necessary to work en high Jtocl concentrations. Reection Rate Constents: In the expression for the rate of reaction -de/dt = k B(c,d) eis the concentration of oxidizing substances and d that of NOL et the time t, es determined by titration. In order to determine the wey in which the reaction rate denends upon the two veriables ¢ and d, we gen assume various funetions and eveluate the expression, solving for k. The constancy of k with varying velues of ¢ end d (i.e. from run to run) is the test that whould select the proper form of the function of the reaction. The constant Ek can be evaluated from the sbove equation in the form of the definite integrel, using the zxperimental date for eny pair of points in © run. However, the formetion of the integral necesserily involves the stoi~ chionetric relationship between c and ds. As was mentioned ~35— above, the increase in d is not identical with the decrease in ¢, end apparently their relationshivs vary from run to run. + a better way of testing the constancy of k involves the graphical determination of the slope of the curve. With reasonable care its valve can be obtained with less that 10% errore The values of ¢c and d to substitute in the funetion are read off he curves at the point where the tangent is taken. in this WEY , different funetions of ¢ and a4 of the form otd? were tried. m and n were varied separately, being given tne values 1/2, 1, 3/2, 2, ete. Of sixteen forms tried, seven of the functions gave about the same constency in k; for the other nine, k varied over a much wider rense. Another method of attack is the following. If between any two runs at the same temperature, the value of either c or d is the same while the value of the other variable is different in the two runs, one can determine roughly from a consideration of the concentrations and retes involvec the manner in which the rate changes with one of the veriables. However, the results of these comparisons were not decisive, partly at least because enough really compeareble runs were not eveilable. lechenism: The following set of equations represents the mos satisfactory mechanism that has been worked ovt up to the oresent time. I. EtocL + HCL —g <=ZEtoH + Cl TI. HtOCl + EtOH —~» CH.CHO + EtOH + HCl. | | -36- "TET. EtOCL + CH,CHO —+ TtoAo + HCl In Run#2 we see that EtOOL alone does not react at en avpresieble rate, but that the prodvets of some slow reaction serve to ecsellerate the decomposition. According to tre equilibrium reaction (I.) HCl is necessary to the formation of StQk which in turn is necessary for the further decom :osition of Et0Cl. Also, the presence of excess elcohol or cldehyde should speed the reaction. No runs were made with aldehyde added. Runs §$9,10, and 11 all contain excess alcohol. as pection of the curves shows, the slopes are appreciably erester than runs et the same temperature and comparable concentrations not conteining eny edded alcohol. (Compare +93 ena #8, or “LO end #12) Up to thes point, no assumstions regarding the above series of reactions other than those implied in simply «writing them out have been meade. Reaction I. can have any reasonable velue for its equilibrium constent, end the equilibrium may be otteined slowly or repidly. The relative rates of reactions IT II. and III. are of no immediate importance to the above considerations. Before specific reaction rate constants can be celeuleted it is necessary to make essumptions regarding the above reactions. First, we will assume thet reedtion I. is rapid end reversible. This assumption implies that reactions II. and III. are the rete controling factors. For their retes, we gan write the expressions: | -de/dt = kp.(EtOC1)(EtoH) * k..(UtoCl)(CH.CHC) rz In the sbsence of date on the soneentration of aldehyde, we cennot celeulats kg. However, if we assume that citer the initial stages of the reaction are over, & more or less steady state with respect to aldehyde concentration is attained, ky (st0cl) (Stow) = k,,(BtoCl) (CH;CHO) and -de/dt = 2&k,(Stocl)(Etc#) Substituting for (2toOCl) its velue in the equilibrium exvuression (2t0H)(Cl.) _ x (TEtOCT) (HEL) ~~ . The rate expression becomes Oy “y Pa K (HC1) or ~de/at = k(EtOH)*(cl.) / (HC1) vy In the runs in which the st g srting materiel was atocl, with no added alcohol, the velue of the Cl, concentration equais the concentration of alcohol. ‘Sines the iodine titration cannot distinguish bctween ol, and EtOC1L, the curve plotted represents actually the sum of Ztocl and Clo. & further assumption must be made before it is possible to use the analyticel data for the purpose of calculating rate conctants, nemely, that the equilibrium in reaction I is so far to the right that the consideration of the iodine titration as a measure of the ¢ 2 concentration introduces no appreciable error. The accompanying tabke showc the ecaleuletion of the rete conetants uhder the above at eble of Reeetion Rete Conetents: Run 7¢ Sime {rin) ‘one ECL (d) Cone. Cl, ox 10° Sone 2tOe b (= sa/t tort) 2¢) a a wols/liter = = fe) ffl) wee ee = 10° 1 50 Oe5 O.LES7 3.1160 156 fo 3.74 L nee 50 2.8 G.1l1L52 0.1855 188 ec 7.5 i. LEB 5 £220 G.0872 G.1401 275 e 5.97 3 360 50 5675 0.0750 62.5 3 4.38 g 270 50 6.3 0.0669 7269 3 5.49 o 150 50 12.5 0.0556 102 e 6eO1 4 £40 50 1.50 0.C110 58.0 3 4,5) 5 190 50 £5.0 0.1452 1100 ry 3,30 5 145 50 30.6 0.1578 0.2400 158 @ 3.07 5 685 50 50.5 9.1168 0.2516 1780 C 331 é 260 40 10.6 0.0846 i 0.1168 259 G 405 ie) 140 40 121.5 0.0452 3.1290 £14 fed 2.58 6 506 40 21.0 0.0208 0.1404 276 e 1.58 7 180 40 7.0 020469 6.1201 173 is) 1.98 3 545 40 2.00 0.0587 0.0792 49.8 is) 2.56 2 270 40 one) 0.1019 0.0616 25 0 01616 0.655 10 125 40 19.0 G.0670 0.9649 27.4 0.2549 0.856 iL L175 40 v1.6 0.1956 0.0694 5504 0.2884 1.05 il 90 40 ne) 0.1610 0.0998 99.5 0.3188 0.706 1l 45 40 6222 0.123 0.1245 195 0.3455 0.530 Les 165 40 505 0 -0300 . 6.1141 148 3 1.27 ~38= assumptions. The slopes of the curves given in the table were °o btained graphically. The agreement is not very satisfactory. oO For example, the rate constents of Runs 9, 10, and 11 are all somewhat Low. However, the variations in the conditions of the different runs arc considerable, and one gen expect that factors negligible in one run will exert an appreciebls influence ia a another. | observed by considering the changes in the conditions of th es to have 0g wn runs, and the effect one would expect these chan on the relation between the velocities in reactions II and III, or in the position of the equilibrium in reaction I, speculation of this sort has no special significance for the present purpose. It is clear that there are too many inter-related reactions to permit a sound quentitative treatment of this system without further information. The most profitable line for additional work on this problem seems to be the seperate a study of resetions © and 5. This might yield cata thet would 2 be guite useful in clarifying not only this problem, but also the more general one of the mechanism of chlorine substitution. Temperature Coefficient: The temperature coefficient of reactions are usually revorted as the retio of the reaction rate constants at T 10 end 7 °C; 210 = Kee 10 / Lae Temperature coefficients hove been found to very for different m mo! ad e ce) pom rt oa “ a) . M fe} — a a ° wm Oo S ose <i Cl @ doc a — i co . Oo a rt oO i) Oo SS ee J fo) . GS oa a i) _S + ra) Go on) — CQ Q ~ B od G SG oO rd o OQ a os 4 son oO & “— qo uS Ki Oo ra) w ren] o Py ~~ a a oof 4 om +s ea met Sy ou © 3) ° o oOo FH Mm Fs oO ato > choy © f4 4d OO a o rf w FS Oo 8 OO SS El 8 Lop ord yy ro co) o 4 ro) S 5 Kad i © oO 63 ad Dy off rt ~@ ow oy a nal ay e r~ al Wo w oO GA ee re Qo KD rol « yy 3 c Qo g bd . . a) OQ oO sy et ad _— co > oO rj et o $3 we rep) A mQ uD -_ ° 2 oO * fan a} a oO a 42 o (0p) co oO © ma ey a “ a) ae Oo ee) ww roof com) CO ° eed sa Mal hort 3 a CO ° oat eis a By og rs Oo rf ~~ ° g ee on ‘ct ct oO rs ma) 0 ~~ RD o oO m ro) ao Ea} a S oad * be = m4 ro) CO ed i m 0 © 4 rd ro) 3 ie) fo) ws Ne) oO ; oj as) n> o - : se o > w 4 Oo 4 Ps ed my ort S4 + oO S q ° Q a a] io) SH a ca) ad ® 4 a4 vad a 54 wt ue iS] ea) * bl cy ce 0 Gy 3 wa a fe) rt a &) oA os) * ce) oh 5 SH Hi re a “sp « ort m p eed * oO e > © is) tos Ea Oo » G om ta Qe - O vy @ 2 O er 4 wD fe) Q o Oo 2 a ca ry m a) od my xe ped cab) nm Q@ w~ 2Q we OO VY o Oo - Pa ct wo rat q co cS wa is re) oO oO ba n wa 63 nd Cy FO bey ¢. qd Oo 2 a Pp Ss - wt o 1s sf) a) ite) 2 H " - 7 Oy SS OQ wi 2 a ® Poo i ws ro) sq Peo Pa us us a) SB 4 2 8 oy +4 8 @ ar cs Fre] 43 fa Q ro) S w as) eS ad - oa cS > ad oO . G Po 4 S ocd wa N ro art ort Hy tf) ret =) ae) ras) ag =) a ae) » g g w ad Be oS ie) o oS M4 @ we 9) ce) ret) fy ea pa td i 6g as 4 rod -t Oo? w> w> fy ~Q Oo SM ord Gof PP » © " DQ Oo ct fa) ci oO ca G4 oO sy ri SS o oO rd aN an) Ht LO ce] CO art oO [o)