Title solubility of compressed acetylene.

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Chemstry of 18 ssue Date 1954-09-10 URL http://hdl.handle.

1 Ttle The solubltes of compressed acet solublty of compressed acetylene Author(s) Hraoka, Hroyuk Ctaton The Revew of Physcal Chemstry of 18 ssue Date URL Rght Type Departmental Bulletn Paper Textverson publsher Kyoto Unversty

2 The Revew of Physcal Chemstry of Japan Vol. 24 No. 1 (1954) THE SOLUBLTES OF COMPRESSED ACETYLENE GAS N LQUDS, The Solublky of Compressed Acekylane Gas n Wa}er BY HROYUR HfRAOKA ntroducton The measurements of the solublty of compressed acetylene gas n acetone were performed early by M. P. E. Berthelot and P. M. E. Veulle` and W. Sller * and recently by P. Holemann and R. Hasselmannrl. The measurements of ts solublty n other lquds, however, have not been done yet. Now then, n ths experment, the solublty of compressed acetylene ga4 n water s measured n the range of pressure from 5 to 40 kg/cm' and that of temperature from 1 to `C, usng the bubblng method. There s a plan to extend ths study over other lquds. -Apparatus and Mekhod ~f v. c ~Y y w BC B ~; ~; ~; ~,,; ;; -----' a A N Flq 1 8 h F6 2 1) c. P. 1) Holemann and R. Hasselmann, Clunr. ng. T cg.. 25, 466 (1953)

3 The Revew of Physcal Chemstry of Japan Vol. 24 No. 1 (1954) 14 H. Hcaeoxn The expermental apparatus conssts of the parts of the hgh pressure cylnders and the lqud phase analyser shown n Fgs. 1 and 2, respectvely. n Fg. 1, a glass vessel of about 400cc, s whch water s flled to one thrd capacty at the start of each run, s nserted nto a cylnder A. The end of the ppe (lmm n nner dameter) shown by a dotted lne n the cylnder, s about 2cm apart from the bottom of the glass vessel. A large cylnder B of about 0 cc capacty s used as a reservor to keep the pressure flactuaton as small as possble durng the samplng and also n the course of the bubblng procedure, and moreover serves to make the temperature of the nlet gas that of the thermostat prevously. A, B and ther ppe lnes between them are below the level of the water n the thermostat, whch s held at constant temperature wthn --1-1/ C. Vs are hgh pressure valves and G s a Bourdon type gauge by whch pressure can be read accurately wthn the error of 1 / of the pressure used. The samples are taken out through V whch s connected to the apparatus of the lqud phase analyser shown n Fg. 2. n Fg. 2, a s a lqud burette graduated to O.OScc, b a gas burette, each bulb of whch havng 35cc capacty and c also a gas burette graduated to O.lec. A, B and C are mercury reservors belongng to a, b and c, respectvely. M s a manometer, by means of whch the pressure n the burettes s kept at the barometrc one. All the burettes are held n the water jacket and kept at constant temperature by crculatng water. The purty of acetylene gas s from 99.5 to 99.6 : and the water used as a solvent s free from the carbon doxde dssolved n a dstlled water. The procedures to establsh the equlbrum from both sdes of the hgh pressure and the low pressure are the same as adopted by R. Webe et al.'> to brng about the equlbrum and from the results obtaned no dfference s found between the two approaches. The experment s conducted n the followng manner. Acetylene gas s ntroduced nto the part of hgh pressure through V, to replace the ar n t, and compressed to a nearly desred pressure, then all valves except V, are closed. After keepng the thermostat at the desred temperature, the gas s bubbled at the rate of about 2 ltres per mnute. On carryng out the bubblng procedure, V, s opened and V. s closed. Then the compressed gas s led nto the apparatus through V, and s allowed to expand to the atmosphere through V;, so as to keep the pressure at a requred level, whch s several to ten per cent hgher or lower than a desred pressure, usng the pressure gauge of the compressor. After ths procedure V; s closed, Va opened and the gas allowed to escape through V6 to keep a desred pressure by means of the gauge G. After the bubblng procedure s fnshed, V_ s opened and V V, and V~ are closed. f the pressure change s recognzed standng at rest for several hours, the gas s bubbled agan at a desred pressure, because the system s not n equlbrum. 21 V. L. Gaddy. R. Webe and C. Hers, Ld. Eng. CHtnr., (1932); J. Am, Clmur. Sot., 55, 947 (1933)

4 0 The Revew of Physcal Chemstry of Japan Vol. 24 No. 1 (1954) The Solubltes of Compressed Acetylene Gas n Lquds, 15 After equlbrum s establshed, the lqud phase analyss s carred on n the followng procedure. Frst, V_s s slghtly opened n order to replace the gas n the ppe between V, and V, wth the saturated soluton. Then both heads of the mercury columns of manometer beng balanced, the cock f s closed. As V, s slghtly released, the cock g or h s opened and the bulk of gas separated from the water s collected n the gas burettes, nearly at the barometrc pressure by the mercury reservor B or C. After a certan nuantty of the sample s taken out, V, s closed and the pressure n the burettes s kept correctly at the bazometrc one. The quantty of the lqud samples taken out s 3 or 5cc. After standng for a long tme n order to reach the equlbrum at the temperature of the water jacket and the bazometnc pressure, the lqud and the gas are measured n the burettes of the lqud and gas, respectvely. The pressure drop n the hgh pressure appararus due to the samplng s recovered so rapdly that the pressure fall would not gve the measurable nfluence on the equlbrum n the apparatus. The pressure fall observed s wthn 1% of the total pressure. Accordng to the above mentoned procedure, the next samplng s performed n successon. The results of these measurements are reproducble at each temperature and pressure. Resulks The results expressed as the number of cc of acetylene (S. T. P.) contaned n lg of water, whch s denoted by r hereafter, are gven n Table 1. n Fg. 3 the number of cc of the gas (S. T. P.) per gram of water s plotted aganst the total pressure or za 4 c c"~. ~, C Lc 6~.'\ a ~: a ]s ~o ]0'C a' a~.~ ~. a"~ 3VC Presau r< rc j, Fueac[s 5 to v 'LO a ss d0 Pressure or Fugacty, kg/cm= Fg. 3

5 The Revew of Physcal Chemstry of Japan Vol. 24 No. 1 (1954) lf H. H~woxn ' Table 1 Temp. Press. kalcm= The e~ solublry~of acetylene n water (cc~hjb-hx s.o 7 4, ll ~ C.5 40 tb Table 2 The absorpton coeffcent of acetylene n water (x-c:dfcc-h_a/kg/cm-) Temp, C Press. k8/cm' s z6 ~ 1.033* L ZG L.oo oss2 L.6o L os1 o.; s~ The values of L. W. Wnker the fugacty of the acetylene. n order to correct for the gas quantty dssolved n the lqud burette, the values of L. W. Wnklers are added to the amounts obtaned from the gas burettes. The total pressure s assumed to be equal to the partal pressure of the acetylene gas n the hgh pressure appazatus, because the vapor pressure of water s neglgble compared wth the partal pressure of acetylene, whle the vapor pressure of water n the burettes s taken nto account, as t s not to be neglected wth the bazometrc pressure. n Table 2 the absorpton coeffcents of acetylene n water defned by equaton (1) are gven, a=f Vzyz (cc-c:h,jcc-h:o/kg/cm=) () where f s the fugacty of acetylene gas and Vo s the number of cc of the gas (S.T.P.) dssolved n Vc cc of the lqud and n the values of Table 2 the densty of the water 3) L. W. Wnkler, LandalbBurnsltn, ;lat. Cr1. Tabfe,

6 The Revew of Physcal Chemstry of Japan Vol. 24 No. 1 (1954) The Solubltes of Compressed Acetylene Gas n Lquds, 17 ' s constant assumed at to be each 1.OOg. t s notced from Table 2 that the absorpton coeffcent s temperature. Table 3 The fugacty of acetylene (cg/cm') Temp_ Press. kg/cm" D G The fugacty of acetylene gas s calculated by graphcal ntegraton usng the state dagram measured by R. Kyama et al. > and equaton (2), n P =- f a 11 PZdP' Z=RT (2) where J, P, V, T and R are fugacty, pressure, volume, absolute temperature and gas constant, respectvely. The values of the fugactes calculated from the dagram of R. H.vewtons) are about 2:b lower than those gven n Table 3. From Fg. 3 or Table 2, equaton (3) s derved, r=k. f (cc-cah:/8-ha0) (3 ) where K s constant, and numercally equal to a n ths experment. n Tables and 2, and Fg. 3 the data above 5kg/cm' at 1 C and 15kglcm' at 10 C are not gven, because the measurement s not to be performed owng to the abnormal phenomena descrbed below, whch take place above 7kg/cm' at 1`C and kg/cm= at 10 C. That s to say, under these condtons the crculaton of the gas s frequently nterrupted. From the gradual decrease of the pressure at rest after the bubblng procedure, t may be assumed that the equlbrum s not establshed. n the case above mentoned a small quantty of the water evolves a large quantty of the gas whch s unable to be measured by the present apparatus. So, t should be consdered that some substance, maybe acetylene hydrate*, s formed at these and pressures, and the soluton becomes hgh vscous due to ths sub- temp ratvres stance. 4) R. Kyama, T. kegam and K. noue, Ths Jourral, 21, 58 (1911) 5) R. H. Newton, nd. Eng. Chenr., (1935) r The detals of ths hydrate wll be reported.

7 The Revew of Physcal Chemstry of Japan Vol. 24 No. 1 (1954) RADKA Table 4 The heat of soluton Lp xal~ (Kcal/mole) Pressure, 0 kg/cm' 1 so xp~"r LS xpf[a` Lp u[. s xe~'~o' fo- /" , t o~ as v ' f the heat of soluton s expressed by Q and assumed to be constant at a gven pressure n the temperature range of ths experment, the relaton between Q and absolute temperature T, s thermodynamcally gven by equa- J ~ ~ ton (4 ), whch holds for the 1/T'x 109 present acetylene water soluton Fs. 4 from equaton (3), where Q s postve n the case of exothermc dssoluton and C constant. A plot of values of the logarthm of the solublty as a functon of the recprocal of absolute temperature s gven n Fg. 4, and the values of the heat of the soluton calculated, usng equaton (4), are gven n Table 4. As wll be seen from Fg. 4, straght lnes are obtaned for any pressures and the heat of soluton s decreased wth the ncrease of pressure The author has great preasure to express hs hearty thanks to Prof. Ryo Kyama, Dr. Jro Osug and Mr. Kezo Suzuk for ther knd gudances throughout ths re search and ther revsons of ths paper. The author s ndebted to the Department of Educaton for the Grant n Ad for the Fundamental Scentfc ndvdual Research shared out Prof. Ryo Kyama. The Laboratory of Physcal Chemstry, Kyoto U~lversty.

TitleSynthesis of melamine from urea, II.

TitleSynthesis of melamine from urea, II. TtleSynthess of melamne from urea, II Author(s) Knoshta, Hdeo Ctaton The Revew of Physcal Chemstry of 7 Issue Date 9-0- URL http://hdl.handle.net//7 Rght Type Departmental Bulletn Paper Textverson publsher