Methylation process chemistry

Alternatives to the methyl chloride dkect process have been reviewed (31). Processes to make phenyl and ethyl siUcones have employed dkect-process chemistry. Phenyl chloride has been used in place of methyl chloride to make phenylchlorosilanes (15). In addition, phenylchlorosilanes are produced by the reaction of benzene, HSiCl, and BCl (17,31). EthylsiUcones have been made primarily in the CIS, where the dkect process is carried out with ethyl chloride in place of methyl chloride (32). Vinyl chloride can also be used in the dkect process to produce vinylchlorosilanes (31). Alternative methods for making vinylchlorosilanes include reaction of vinyl chloride with HSiCl or the platinum-catalyzed hydrosilylation of acetjdene with HSiCl. ... 

In an effort to understand better the catalytic chemistry associated with this reaction, the reactivity of dodecylnitrile or dodecylamine was measured under the same experimental conditions. The results listed in Table 1 show that the nitrile and the primary amine are much more easily transformed into N-dimethylalkylamine than the ester or the acid (Table 2). The rate determining step in the methylation process is directly related to one of the first reactions converting the ester or the acid into nitrile. It can be assumed that ... 

Methyl formate chemistry. The first step in the carbonylation process for formic acid, formamide, and DMF is the production of methyl formate via the reaction illustrated in Eq. (25) ... 

Fatty acid methyl ester (FAME) sulphonation Summary sulphonation reaction process chemistry... 

Up to this point, the focus has been on improving the yield of the catalytic reaction to reduce CO2 emission. However it is important to consider entirely new process chemistry that might reduce the number of steps, lower the temperature, and as a result, also lower CO2 production. An excellent illustration of this point involves the production of methyl methacrylate (MMH). Current commercial catalytic routes use C4 feedstocks and involve two high-temperature gas-phase catalytic steps followed by esterification. The first two steps occur above 350°C with an overall yield of about 75%. The main by-product is carbon dioxide. A new process to methyl methacrylate is under development by Asahi Chemical.This process combines the second and third steps into a single oxidative esterification step... 

The Eastman acetic anhydride [108-24-7] process provides an extension of carbonylation chemistry to carboxyUc acid esters. The process is based on technology developed independendy in the 1970s by Eastman and Halcon SD. The Eastman acetic anhydride process involves carbonylation of methyl acetate [79-20-9] produced from coal-derived methanol and acetic acid [64-19-7]. 

Herm/es/Djnamit JS obe/Process. On a worldwide basis, the Hercules Inc./Dynamit Nobel AG process is the dorninant technology for the production of dimethyl terephthalate the chemistry was patented in the 1950s (67—69). Modifications in commercial practice have occurred over the years, with several variations being practiced commercially (70—72). The reaction to dimethyl terephthalate involves four steps, which alternate between liquid-phase oxidation and liquid-phase esterification. Two reactors are used. Eirst, -xylene is oxidized with air to -toluic acid in the oxidation reactor, and the contents are then sent to the second reactor for esterification with methanol to methyl -toluate. The toluate is isolated by distillation and returned to the first reactor where it is further oxidized to monomethyl terephthalate, which is then esterified in the second reactor to dimethyl terephthalate. 

Sanding is carried out at this stage and, after clean-up, the final colour or top-coat is applied. There is some variation in the resin chemistry used. Alkyds crosslinked with melamine-formaldehyde are widely used for non-metallic pigmentation. Metallics are usually based on acrylics for better durability. The acrylic may be thermoset with melamine-formaldehyde or a thermoplastic lacquer (plasticised copolymer of methyl methacrylate). A thickness of about 50ftm is applied and stoved for 20 min at 130°C (lacquers receive a bake-sand-bake process for a smoother appearance). 

Alkylcatechols are important as chemicals and chemical intermediates in the fine chemistry industry for the synthesis of flavouring agents, agricultural chemicals and pharmaceuticals [1]. 3-methyl catechol has a special value from the industrial point of view. Previously y-alumina was found to be an effective catalyst for the gas-phase methylation of catechol with methanol [2]. The process can be schematically presented as ... 

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