Processes 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. ... 

Typically, this rearrangement process is catalyzed by an inorganic Lewis acid and inorganic or quaternary onium iodide in a polar, aprotic solvent (e.g., ZnR, KI, N-methyl pyrrolidone) (8,9). For years, however, commercial processes utilizing this chemistry were unattractive due to the high cost of 1 and poor reaction selectivity. 

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 ... 

Problem 32.8 Graft copolymers can be made by each of the following processes. Show the chemistry most likely involved, and the structure of the product, (a) Polybutadiene is treated with styrene in the presence of a free-radical initiator, (b) Poly-(vinyl chloride) is treated with methyl methacrylate in the presence of benzoyl peroxide, (C,H5C00)2. 

Of the methacrylics, methyl methacrylate (MMA) is by far the most important intermediate, with a production of approx. 2 X 10 t/a (1.6 X 10 t/a for Europe and USA [la]). It finds its main application in polymers as Plexiglass or Perspex, a crystal-clear artificial glass with high hardness, resistance to fracture, and chemical stability. About 80 % of the MMA is produced on the basis of the Acetone-Cyano//ydrin (ACH) process [lb]. This process involves stoichiometric chemistry and is characterized by an overall yield of MMA of about 80 % (based on acetone) with the stoichiometric production of about 2.4 t of ammonium bisul-fate/sulfuric acid waste per ton of MMA. This process is therefore faced with increasing environmental costs. As a consequence, several alternative catalytic processes for MMA production are - and have been - under development. 

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) ... 

Acetic Anhydride via Methyl Acetate Carbonylation. The second major development, pioneered by Tennessee Eastman (25) is the carbonylation of methyl acetate to acetic anhydride, which also comprises the first example of a totally integrated synthesis gas-based process for such chemistry, dependent entirely on coal as feedstock. 

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

Conjugated dienes can be selectively hydrated to ketones in the presence of cationic ruthenium complexes with bipyridyl ligands. The role of ruthenium is to catalyze the isomerization of allylic alcohols formed by the addition of water to diene. This method allows one to convert butadiene to methyl ethyl ketone in high yield [187]. Hydration of triple bonds is one of the oldest catalytic processes of organic chemistry. Though this reaction has no industrial value, it can serve as a tool of fine organic synthesis. The hydration can be catalyzed by rhodium salts under phase-transfer conditions [188]. The more exotic process of the hydrolysis of phenylacetylene to toluene and carbon monoxide catalyzed by ruthenium complex should also be mentioned [189] ... 

To explain this outcome 1,2-migration of a methyl group has to be assumed, and although this is a rare process in organoaluminum chemistry it finds a closely related parallel in a thoroughly studied cuprate process [14]. 

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]. 

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