Grades methyl chloride

A representative technical grade of methyl chloride contains not more than the following indicated quantities in ppm of impurities water, 100 acid, such as HCl, 10 methyl ether, 20 methanol, 50 acetone, 50 residue, 100. No free chlorine should be detectable. Traces of higher chlorides are generally present in methyl chloride produced by chlorination of methane. The boiling point should be between —24 and —23° C, and 5—95% should distill within a range of about 0.2°C. It should be clear, colorless, and free from visible impurities. 

A schematic flow chart of this process is shown in Fig. 6. The feed is composed of 25-35 wt% purified isobutene and the required amount of isoprene (0.4-1.25 wt%), dissolved in cooled liquid methyl chloride. Purity of supplied isobutene is variable and preliminary drying and fractionation in a two-tower system remove water, n-alkenes, f-butanol, and diisobutenes. The polymerization grade (>99.5%) fresh isobutene is then mixed in a feed blend drum with isoprene (purity >98%) and a recycle stream of diluent and unreacted monomers. A concentrated catalyst solu-... 

Materials. The purity and analysis of isobutene, methyl chloride, and aluminum chloride have been described (16). Ethyl chloride gas (U.S.P. grade, 99.99% minimum purity, Matheson Co.) was further purified by scrubbing through Molecular Sieves (5A, Linde Co.) and BaO, and distillation into the dry box. Vinyl chloride (99.9% minimum purity, Matheson Co.) was distilled into the box, cooled to —78° C., and filtered cold until free from solid matter. Propane gas (instrument grade and natural grade, Matheson Co.) was passed over Molecular Sieves and then condensed into the box. 

Methyl cellulose and hydroxyalky methyl cellulose manufacture involves in part Williamson synthesis with methyl chloride and alkoxylation. The various ethers are used primarily in building materials and in industrial applications (O Table 13). Higher grades with greater purities consist of modified vegetable gums, and they find uses in controlled release applications in pharmaceuticals, and in food products and cosmetics where they serve as emulsifiers and texture agents. 

It was by chance that we found a contact mass, by means of which we could overcome this problem for the first time. Fig. 2 depicts a typical surface structure of the sample "CuCb/Siiech/Zn This sample consisted of technical-grade silicon, 5 wt.% Cu as CuCb and 0.5 wt.% zinc promoter Its especially simple surface structure, see below, was surely due to its short reaction time the sample reacted for only 20 min with methyl chloride. But, already after this short time, it had reached its full activity, see second section, and also its full selectivity for the main product dimethyidichlorosilane (about 80%). 

Artie [Du Pont], TM for refrigeration grade of methyl chloride. 

Materials. Methane (ultrahigh purity grade) was obtained from the Matheson Co. and used without further purification. The following analysis was supplied with the methane C02 - 5 p.p.m. 02 - 5 p.p.m. N2 — 19 p.p.m. C2H6 — 14 p.p.m. C3H8 - 5 p.p.m. Methyl chloride (high purity grade) was obtained from the Matheson Co. and used without further purification. 

Cellulose ethers have the polymeric backbone of cellulose, a natural carbohydrate that contains a basic repeating structure of anhydroglucose units. During the manufacture of cellulose ethers, cellulose fibres are treated with caustic solution, which in turn is treated with methyl chloride or propylene oxide. The chemical reaction yields a fibrous product, which is purified and ground to a fine powder. Commercial grades vary chemically and physically for matching the desired applicative properties. 

The purified isobutylene is then blended with a recycled methyl chloride stream containing a low level of isobutylene ( 5%). Finally, the comonomer, iso-prene or p-methylstyrene, is added. In this blending process, control of the ratio of comonomer to isobutylene is very important. This is because it has a significant impact on the composition of the polymer produced, the conversion of monomer, and the stability of reactor operation. For these reasons, a combination of both an analyzer and a mass balance control can be used to maintain the composition of the feed blend. The feed blend contains 20-40 wt% of isobutylene and 0.4-1.4 wt% of isoprene or 1-2 wt% of p-methylst5Tene, depending on the grade of butyl rubber to be produced the remainder is methyl chloride. 

Methyl chloride is available for commercial and industrial use in various grades having much the... 

A mixed ether, hydroxypropyl-methylcellulose, is also available. This is prepared by treating alkali cellulose with a mixture of methyl chloride and propylene oxide. Commercial grades of the polymer generally have a methoxy content of about 30% and a hydroxypropoxy content of about 5—10%. The mixed ether has increased organo-solubility and thermoplasticity over the methylcellulose counterparts. 

The physical properties of methylene chloride are Hsted in Table 1 and the binary a2eotropes in Table 2. Methylene chloride is a volatile Hquid. Although methylene chloride is only slightly soluble in water, it is completely miscible with other grades of chlorinated solvents, diethyl ether, and ethyl alcohol. It dissolves in most other common organic solvents. Methylene chloride is also an excellent solvent for many resins, waxes, and fats, and hence is well suited to a wide variety of industrial uses. Methylene chloride alone exhibits no dash or fire point. However, as Htde as 10 vol % acetone or methyl alcohol is capable of producing a dash point. 

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