Hydrogen sulfide hydrate

After crystal structure II was deduced, a definitive x-ray diffraction study of tetrahydrofuran/hydrogen sulfide hydrate was undertaken by Mak and McMullan (1965), two of Jeffrey s colleagues. The crystal consists of a face-centered cubic lattice, which fits within a cube of 17.3 A on a side, with parameters as given in Table 2.2a and shown in Figure 1.5b. In direct contrast to the properties of structure I, this figure illustrates how a crystal structure may be completely defined by the vertices of the smaller 512 cavities. Because the 512 outnumber the 51264 cavities in the ratio 16 8, only 512 are clearly visible in Figure 1.5b. 

Simple Hydrogen Sulfide Hydrates with Inhibitors... 

Figure 6.51 Methanol inhibition of simple hydrogen sulfide hydrates.

Figure 6.52 Simple hydrogen sulfide hydrates with various inhibitors.

Hydrogen sulfide hydrate with various inhibitors... 

Glew, D.N. 2000. Aqueous nonelectrolyte solutions. Part XVII. Formula of hydrogen sulfide hydrate and its dissociation thermodynamic functions. Can. ]. Chem. 78 1204-1213. 

The optimum temperature of the cold tower is as low as possible without risking formation of a third phase in addition to vapor and aqueous solution. Table 13.24 gives the temperatures at which solid hydrogen sulfide hydrate or liquid hydrogen sulfide form in the system HjS-HjO. At 300 psi, the minimum safe cold tower temperature is around 30°C. The rapid increase in condensation temperature above 300 psi is another reason for this being the optimum pressure. Before the first pilot plant for the GS process was operated, the possibility of hydrate formation was not recognized, and freeze-ups occuned until the cold tower temperature was raised above 30°C. 

Chemistry, isotopic composition, and origin of a methane-hydrogen sulfide hydrate at the Cascadia subduction zone. Earth and Planetary Science Letters, 156 173-183. 

CHHN2O, 1,4-Dichlorobutane - urea host structure, 38B, 594 CH7AI2NO1oSi2f Dickite - formamide, 42B, 500 C2H8O 7.67 H2O, Ethylene oxide hydrate, 30B, 267 43B, 802 CftH80 H2S 17 H2O, Tetrahydrofuran hydrogen sulfide hydrate, 30B, 268... 

The elastic properties of hydrates are important to understanding the sonic and seismic velocity field data obtained from the natural hydrates-bearing sediments. Data on the mechanical properties of CO2 hydrates are hmited. Table 10.3 shows the elastic properties of ice, CH4 hydrates, and CO2 hydrates. It should be noted that these properties may vary for different guests and occupancies. For example, Kiefte et al. [21] measured the compressional velocity of methane, propane, and hydrogen sulfide hydrates as 3.3, 3.7, and 3.35 km/s, respectively. 

Table 8 Comparison of Theoretical and Experimental Stretching and Bending Frequencies (cm ) for Hydrogen Sulfide Hydrate ...

Arsenious oxide, trivalent antimony (73), sulfurous acid (74), hydrogen sulfide (75), stannous ion, and thiocianate (76) have been recommended for the titration of iodine. However, none of these appears to have a greater sensitivity for the deterrnination of minute quantities of iodine than thiosulfate. Organic compounds such as formaldehyde (77), chloral hydrate (78), aldoses (79), acetone (70,80), and hydroquinone have also been suggested for this purpose. 

In the feed preparation section, those materials are removed from the reactor feed which would either poison the catalyst or which would give rise to compounds detrimental to product quality. Hydrogen sulfide is removed in the DBA tower, and mercaptans are taken out in the caustic wash. The water wash removes traces of caustic and DBA, both of which are serious catalyst poisons. Also, the water wash is used to control the water content of the reactor feed (which has to be kept at a predetermined level to keep the polymerization catalyst properly hydrated) and remove NH3, which would poison the catalyst. Diolefins and oxygen should also be kept out of poly feed for good operation. 

Ethylene imine Hydrazine hydrate Hydrogen sulfide. Hydroxylamme salts Inorganic Hg. compounds lodates Iodides... 

Addition of hydrogen sulfide results in formation of monomeric gem dithiols or trimeric thioketals (511,512). The initially reported thione formation (513-515), analogous to hydration of morpholinocyclohexene... 

Cyanamidopyrimidine (15) was converted to the thioureido derivative 16 by reaction with hydrogen sulfide and ammonium hydroxide and then cyclrzed to 18 with hydrazine hydrate. Cyclization to 18 presumably took place by elimination of a molecule of ammonia from the aminoguanidine intermediate 17 (65JCS3357) (Scheme 11). 

Projections, linearly independent, 293 Propagation, of polymerization, 158 Propane, hydrate, 10, 33, 43, 46, 47 hydrate thermodynamic data and lattice constants, 8 + iodoform system, 99 Langmuir constant, 47 water-hydrogen sulfide ternary system, 53... 

The parameters A, B, and C are dependent on the particular nature of the gas. Katz developed a simple method for gas mixtures that takes the composition of the gas into account [942,1086]. Furthermore, a graphic method is available that permits the estimation of the hydrate-forming temperatures at pressures for natural gas containing up to 50% hydrogen sulfide [129]. 

Gas hydrates are non-stoichiometric crystals formed by the enclosure of molecules like methane, carbon dioxide and hydrogen sulfide inside cages formed by hydrogen-bonded water molecules. There are more than 100 compounds (guests) that can combine with water (host) and form hydrates. Formation of gas hydrates is a problem in oil and gas operations because it causes plugging of the pipelines and other facilities. On the other hand natural methane hydrate exists in vast quantities in the earth s crust and is regarded as a future energy resource. 

Radon forms a series of clathrate compounds (inclusion compounds) similar to those of argon, krypton, and xenon. These can be prepared by mixing trace amounts of radon with macro amounts of host substances and allowing the mixtures to crystallize. No chemical bonds are formed the radon is merely trapped in the lattice of surrounding atoms it therefore escapes when the host crystal melts or dissolves. Compounds prepared in this manner include radon hydrate, Rn 6H20 (Nikitin, 1936) radon-phenol clathrate, Rn 3C H 0H (Nikitin and Kovalskaya, 1952) radon-p-chlorophenol clathrate, Rn 3p-ClC H 0H (Nikitin and Ioffe, 1952) and radon-p-cresol clathrate, Rn bp-CH C H OH (Trofimov and Kazankin, 1966). Radon has also been reported to co-crystallize with sulfur dioxide, carbon dioxide, hydrogen chloride, and hydrogen sulfide (Nikitin, 1939). 

Treatment of nitriles with gaseous hydrogen sulfide in the presence of anion exchange resin (Dowex 1X8, SH from) at room temperature affords the corresponding primary thioamides.27 Treatment of nitriles with 70% sodium hydrosulfide hydrate and magnesium chloride hexahydrate in DMF or methanol affords primary thioamides in high yields.28 Primary thioamides have been... 

Hacisalihoglu, B., Demirbas, A.H., Hacisalihoglu, S. 2008. Hydrogen from gas hydrate and hydrogen sulfide in the Black Sea. Energy Edu Sei Teehnol 21 109-115. 

---