Methyl chloride, 7, 31 Table

The halocarbons, which are not destroyed in the troposphere by reactions with hydroxyl, pass into the stratosphere where they are photo-dissociated to liberate chlorine atoms which attack ozone. Only one of them is of natural origin, methyl chloride CH3CI, but there are also several industrial products, especially carbon tetrachloride, CC14, trichlorofluo-romethane, CFC13, and dichlorodifluoromethane. Methyl chloride (Table III) has a natural marine origin (for details, see ref. 12), but it is certainly present also in the smoke produced when polyvinyl and other products containing chlorine are burnt. In addition, it is produced naturally not only in forest fires, but also in tropical agriculture based on the cultivation... 

Table 2. Temperature Dependence of Vapor Pressure, Density, and Enthalpy of Methyl Chloride...

Production and sales data for methyl chloride, as reported by the U.S. International Trade Commission for the years 1945 to 1989, are given in Table 3. Production grew tremendously in the 1960s and again in the late 1980s. Methanol hydrochlorination was used to produce about 64% of the methyl chloride in 1969 and about 98% by 1974. The principal U.S. producers and their capacities are shown in Table 4 (54). These capacities do not include the 100 + million kg per year used by The Dow Chemical Company, Occidental, and Vulcan to captively produce other chloromethanes. 

Table 3. U.S. Methyl Chloride Production and Price Statistics...

Ref 54. Vulcan has recently bought out Vista. The historical growth rate (1979—1988) for methyl chloride is 1.7% per year. The projected growth rate through 1993 is projected demand in 1993 is 264,000 t. Methyl chloride is used primarily in the manufacture of siHcones (Table 5). Table 5. Uses of Methyl Chloride 1 to 2% per year. The... 

The principal uses of methyl chloride, as reported by the U.S. Tariff Commission, are given in Table 5. More recent analyses by the ChemicalM.arketing Reporter the breakdown in 1989 and show significant changes in the end use pattern. 

The increasing ranges of pressure and temperature of interest to technology for an ever-increasing number of substances would necessitate additional tables in this subsection as well as in the subsec tion Thermodynamic Properties. Space restrictions preclude this. Hence, in the present revision, an attempt was made to update the fluid-compressibihty tables for selected fluids and to omit tables for other fluids. The reader is thus referred to the fourth edition for tables on miscellaneous gases at 0°C, acetylene, ammonia, ethane, ethylene, hydrogen-nitrogen mixtures, and methyl chloride. The reader is also... 

Table 1 lA presents tabulations of the safety of important refrigerants, but this list does not include aU available refrigerants. Table 11-5 summarizes a limited list of comparative hazards to life of refrigerant gas and vapor. The current more applicable refrigerants from the m or manufacturers of the CFC and HCFC refrigerants and their azeotropes/ blends/mrxtures are included, but the list excludes the pure hydrocarbons such as propane, chlorinated hydrocarbons such as methyl chloride and others, inorganics, ammonia, carbon dioxide, etc. See Table 11-6. The CFC compounds have a longer and more serious ozone depletion potential than the HCFC compounds, because these decompose at a much lower atmospheric level and have relatively short atmospheric lifetimes therefore, they do less damage to the ozone layer. Table 11-7 summarizes alternate refrigerants of the same classes as discussed previously. Table 11-8 correlates DuPont s SUVA refrigerant numbers to the corresponding ASHRAE numbers.

Methylene Chloride and Chloroform.—Curves for CH3C1, CH2C12 and CHC13 (Table IX) are shown in Fig. 7. The maximum for methyl chloride lies at 1.80 A. we do not consider this value... 

Copolymers. Copolymers have also been studied (16-18). While one comonomer contains 1-2 quaternary nitrogen in a flexible pendant chain, the other comonomer was nonionic. Copolymers of the methyl chloride salt of dimethylaminoethyl methacrylate (one quaternary nitrogen atom) and dimethylaminoethyl methacrylate (DMAEMA) and of MDTHD (2 quaternary nitrogen atoms) and DMAEMA, N,N-dimethylacryl-amide (NNDMAm) or dimethylaminopropyl methacrylate (DMAPMA) have been studied and the results summarized in Table VI. 

Cost estimators have provided reliable cost data as shown in the following table for the chlorinators in the methyl chloride plant addition. Analysis of the data and recommendations of the two alternatives are needed. Use present worth for i = 0.10 and i = 0.20. 

Table 3 The contribution to the observed secondary a-deuterium KIEs for the SN2 reactions between microhydrated chloride ion and methyl chloride at 300 K. ...

The calculations were performed at the semiempirical level using AMI parametrization. The results for the methyl chloride reaction (Table 8) supported Williams earlier findings for the methylammonium ion-ammonia reaction (p. 147) and the results by Wolfe and Kim in that the inverse secondary a-deuterium KIE arose from an increase in the C —H stretching force constants which accompanied the change from sp3 hybridization at the a-carbon in the reactant to the spMike hybridization in the transition state. More important, however, were the observations that (i) the total KIE is dominated by the vibrational (ZPE) component of the KIE with which it correlates linearly, and (ii) that the inverse contribution from the C —H(D) stretching vibrations is almost constant for all the reactions. Ibis suggests that the contribution from the other vibrations, i.e. the rest in Table 8, determines the magnitude of the KIE. In fact, Barnes and Williams stated that the... 

Table 8 The AMI calculated semiclassical secondary a-deuterium KIEs, the stretching and other contribution to the KIEs and the C—Cl transition state bond lengths for the identity SN2 reactions between chloride ion and substituted methyl chlorides.0...

The reaction of CIO- with methyl chloride can only proceed via the Sn2 process. An inverse KIE of 0.85 is measured (Table 10.3). The reaction with /-butyl chloride presumably proceeds via an E2 mechanism (since Sn2 attack on the Cl substituted carbon is blocked) and the observed KIE of 2.31 (Table 10.3) is consistent with that conclusion. The isotope effects for both species are nearly the same as the effects measured in the condensed phase (compare Tables 10.3 and 10.4) and measure the relative contributions of the two paths. The results indicate that the E2 pathway becomes the dominant channel as the substrate becomes more sterically hindered. 

Table 3. Measured (Black and Law 2001) and ab initio vibrational frequencies for methyl chloride, C CX.Ab initio frequencies are calculated with GAMESS, using the Hartree-Fock method and 6-31G(d) basis set. The ratio of each measured and model frequency is also shown.

Similar plots have been obtained for the gas-phase rearrangement of 35 (A = CH3 Aik = ethyl Alk = methyl) and 36 (A = CH3 Aik = methyl Alk = ethyl) in 720 torr methyl chloride in the temperature range from 40 to 120 Regression analysis of the relevant Arrhenius curves leads to the activation parameters listed in Table 22. 

Devulcanization in the Presence of Benzyl Chloride and Methyl Chloride. The above results suggest that catalyst efficiency might be improved when devulcanization is carried out with added alkylating agent. We find that this is, indeed, the case. Added benzyl chloride or methyl chloride further decreases the crosslink density for a given concentration of catalyst (Table 11). However, 1- and 2-chlorobutanes appear to be ineffective, possibly because of dehydrochlorination. 

All of the modes discussed above present important shifts npon denterinm snbstitution (Table 1). Consequently, the authors came to the conclusion that they mainly involved motions of hydrogen atoms. The isotopic ratios (vh/vd = 1-30 to 1.36) are in this case comparable to those for the hydrogenic stretching and deformations modes found in methyl chloride (vh/vd = 1.31 to 1.37). ... 

Calculated CX stretching frequencies for these compounds (repeating the data in Appendix A7) are provided in Table 7-3 and compared to measured values. As expected, limiting (6-311+G basis set) Hartree-Fock frequencies are all larger than experimental values. In fact, with the sole exception of methyl chloride at the 3-2IG level, Hartree-Fock frequencies are always larger than experimental frequencies, irrespective of choice of basis set. 

As seen from the data in Table 7-4 (abstracted from frequencies provided in Appendix A7) symmetric methyl group CH stretching frequencies change with substitution. The smallest value is for methylamine (chosen as the reference compound) and the largest is for methyl chloride. (Ethane has been excluded from this comparison as the symmetric stretch here involves all six hydrogens.)... 

Methane Conversion. The results for the conversion of methane on praseodymium oxide are shown in Figure 1 and Table I. The major products were carbon monoxide, carbon dioxide, ethylene, and ethane both in the presence and absence of TCM in the feedstream while small amounts of formaldehyde and C3 compounds were detected. Water and hydrogen were also produced. The catalyst produced low methane conversion (ca. 6%) and selectivity to C2+ compounds (ca. 30%) in the absence of TCM in the feedstream. On addition of TCM the conversion of methane after 0.5 h on-stream was increased by almost two-fold (11.9%) and increased still further to 17.2% after 6 h on-stream. The selectivity to C2+ also increased with time on-stream to 43.3% after 6 h on-stream. It is noteworthy that over the 6 h on-stream with TCM present the ratio increased from 1.0 to 2.1. No methyl chloride was... 

Praseodymium chloride pretreated in a helium flow at 750°C for 1 h produced a low conversion of methane and selectivity to C2+ compounds after 0.5 h on-stream both in the absence and presence of TCM (Figure 2 and Table I). When TCM was present, the conversion and selectivity increased to 17.1 and 46.4% after 1.8 h onstream, respectively, and then the values remained almost constant. In the absence of TCM, the conversion and selectivity also increased to 16.0 and 54.5%, respectively, after 1.8 h on-stream while in the latter case the values decreased gradually to 11.7 and 37.2% over 6 h on-stream. Although no TCM was added to the feedstream, methyl chloride was formed in the reaction. After 0.5 h on-stream, the selectivity to methyl chloride was 2.6% but decreased to 0.1% over 6 h onstream. The XRD pattern of the catalyst after the reaction with TCM present in the... 

In Table 3.8, rate constants are given for the reactions of several carbanions with methyl chloride. Most of the data was obtained in a flowing-after glow instrument. 

TABLE 3.8. Rate Constants for Reactions with Methyl Chloride"... 

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