A knowledge of the equilibrium water content of hydrocarbon systems under pressure is important to the national gas industry. The information available on the solubility of water in hydrocarbon, hydrogen sulfide, and carbon dioxide systems is reviewed in this paper and the influence of the more important variables such as temperature, pressure and molecular structure on solubility in liquids and gases is discussed. A suitable chromatographic technique bas been developed for determining low concentrations of water. Tailing of the water peaks bas been eliminated by adding water to the carrier gas stream The method is applicable for both gas or liquid samples and is effective in the presence of hydrogen sulfide. The experimental study of water solubility in methane-hydrogen sulfide systems at a temperature of 16F has shown that the presence o/ hydrogen sulfide causes only a modest increase in water content at pressures up to 1,400 psia. Theoretical considerations and data on pure hydrogen sulfide and carbon dioxide suggest that the effect of both these compounds will be greater at higher pressures and in the liquid phase. Introduction Before transporting or processing natural gases and gas condensates, it is usually necessary to dry them using suitable dehydration equipment. The design and operation of this equipment requires a knowledge of the amount of water present in the fluid at the reservoir and operating conditions. This is influenced by temperature, pressure and composition, particularly when certain nonhydrocarbon components are present. Field experience indicates that hydrogen sulfide and carbon dioxide, for example, alter the usual water solubility relationships appreciably. However, an extensive search of the literature does not reveal any quantitative data on such systems. For sweet natural gases, generalized empirical correlations such as the one proposed by Katz, et al, can be used to predict water solubility with confidence at most temperatures and pressures of interest. However, existing theoretical relationships do not permit a calculation of the deviation from these curves when polar substances like hydrogen sulfide are present in the system. Thus one must resort to an experimental approach to obtain the necessary information. The fact that laboratory experimental methods frequently involve the use of mercury which reacts with hydrogen sulfide in the presence of water, and that hydrogen sulfide interferes with many chemical reactions specific for water has contributed to the difficulty of studying water solubility in systems containing hydrogen sulfide. In this investigation the water content of a limited member of methane-hydrogen sulfide mixtures was determined using a special technique with gas chromatography. REVIEW OF PUBLISHED DATA Experimentally determined water solubility data have been reported for methane, ethane, propane, n-butane, 1-butene, hydrogen sulfide and carbon dioxide. These studies report the effect of pressure, temperature and molecular structure on water solubility in single component gases and liquids. SPEJ P. 293^
ether. This is based on the fact that the changes observed in the infrared for chlorophyll b in ethyl ether did not occur in chloroform even when the mole ratio of trinitrobenzene to chlorophyll b was 18:l. Consequently, a sufficient amount of complex is not present for the nnir runs of chlorophyll b in order to gain much information about the system. There obviously is some complexing since the proton resonance of trinitrobenzene is shifted about 60 cycles to higher fields indicating it is within the diamagnetic shielding zone of the chlorophyll ring. Also there is a considerable paramagnetic shift of the phytyl oxygen bonded methyleiie group. The only proton which experiences n diamagnetic shift is the cy proton. It seems likely that the system here would be quite similar to the chloropliyll a complex. The shift of methylene protons is again inlerpreled its arising from displacement of the hydrocarbon tail from the region of the ring by trinitrobenzeneThe conclusion that chnrge-transfer interacl ion occurs in the vicinity of the cy and 0 protons of lhe chlorophyll molecule is in disagreement with some of the current opinions which regard the cyclopentanone region (ring V) an important center of high electron density.However, it seems quite logical that the area of the chlorophyll molecule which will be involved in electron donation will depend on the environment in which the molecule is placed. It is very likely that solvent perturbations will be a major factor in determining this region. Furthermore, steric considerations with the acceptor molecule must not be neglected. This may be a contributing factor in the present situation. If the hydrocarbon tail is preferentially oriented in such a way that it is within the vicinity of the porphyrin head as ninr results imply, then perhaps large molecules, such as trinitrobenzene, must interact with the upper part of the chlorophyll molecule where steric interactions with the tail are minimized. Obviously it would be of interest to investigate systems like the one presented here or else similar ones in various solvent systems. A systematic stjdy of this type could reveal what role solvent plays in influencing the site of electron donation. Nelson13 has investigated the electronic energy levels in chlorophyll derivatives. He found values of 4.03 eV for ethyl chlorophyllide a and 5.16 eV for ethylchlorophyllide b. This means that ethyl chlorophyllide a is a better electron donor than ethyl chlorophyllide b in the solid film. If solvent effects are small, the binding constants for TNB in ether should be larger for chlorophj7ll a than for chlorophyll b. This is what is observed here. A quantitative correlation has not been made. Acknowledgments.The cell Zn(Hg)IZnClz(s)lIAgX in pyridinelAg(s) has been used to study the behavior of the nitrate, picrate, chloride, cyanide, and thiocyanate of silver(1). Correlating the potentiometric behavior with the conductance data for these different silver salts eventually made possible the evaluation of the standard potential of the reac...
An iterative method has been devised for the simulation of chemiluminescence data during the oxidative decomposition of aa' azobisisobutyronitrile in the presence of ethylbenzene. From this simulation the cross termination rate constant of the two types of peroxy radicals present has been estimated.
47longer abrasion period, showed that they have a segmented structure ( Fig. 2(A)) similar to that commonly observed on a larger scale in metal cutting; this structure is believed to arise from instability of plastic flow during chip formation.'The chips are heavily distorted, but no details of a dislocation substructure could be resolved. Numerous dark spots ~1 0 0 A in diameter were seen in the chip structures. The electron diffraction pattern from a complete chip ( Fig. 2(B)) shows broad rings containing sharp spots, consistent with a heavily distorted matrix containing small crystallites. Dark-field images formed using diffraction spots on the diffuse rings confirmed that the dark spots in Fig. 2(A) are small crystallites. The chips recrystallize when they are annealed at 500" to 700"C, apparently by the growth of the crystallites, to produce a fine polycrystalline structure. The crystallites present in the chips therefore appear to be recrystallization nuclei. It is well known that temperature transients of several hundred degrees may be produced during abrasive wear; and it is possible that the nuclei are formed by the heating of chips by the plastic work done during their formation.The profiles of abrasive particles approximate negativerake-angle cutting tools; an analysis of the grinding of metals on this assumption suggests that frontal and lateral bulges are formed as the particles move across the surface? A mech-anism of material removal during the abrasion of rutile may be postulated on this basis. The stress distribution at the point of contact between the specimen and an abrasive particle with negative effective rake angle is such that plastic deformation under compressive constraint occurs in front of the particle as it moves across the surface. Since the groove cut is narrow #compared to the grain diameter, the plastic zone is effectively located within one crystal for a considerable part of its length, and the usual restriction on plastic deformation in a polycrystal because of the limited number of slip systems will not apply. The large plastic work done as a result of the high yield stress results in a significant increase in temperature in the plastic zone, considerably reducing the yield stress and thus favoring further plastic; strain? The bulge formed eventually becomes unstable and shears in front of the abrasive particle, forming a segmented chip, and at the sides of the particle, forming fins. Cutting of a previously distorted surface will occur as abrasion is continued and will probably result in changes in the detailed structure of the debris fragments. HE enthalpy of fusion of Pb,SiO, was determined using T quantitative DTA.' Measurements were made with a noninductively wound resistance furnace containing 3 symmetrically positioned P t sample holders 3/s in. in diameter mounted on Pt-PtlORh thermocouples with thermocouple wells extending approximately halfway into the sample holders.20a Calcined ALOa was used as a reference material, and reagent-grade KCl (AH1=84.5 cal/g)' served as a...
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