Acetone, purification cyanohydrin

One of the most important appHcations of this process is that of methyl methacrylate manufacture. In this process (81), acetone cyanohydrin is treated with sulfuric acid at 100°C, affording the corresponding methacrylamide sulfate which is esterified with methanol. After purification, methyl methacrylate (99.8% purity) is obtained in a yield of ca 85%. 

The two established Hnls, those from L. usitatissimum and P. amygdalus, have found biocatalytic applications for the production of (i )-cyanohydrins. The former of these Hnls is the least widely applied, the natural substrates being acetone cyanohydrin or (i )-2-butanone cyanohydrin (Table 1) [28]. Although an improved procedure for the purification of this enzyme has been reported [27] it is still only available in limited quantities (from 100 g of seedlings approximately 350 U of enzyme are obtained). It was found that this enzyme transforms a range of aliphatic aldehyde and ketone substrates [27], the latter of which included five-membered cyclic (e.g. 2-methylcyclopentanone) and chlorinated ketone substrates. In contrast, attempts to transform substituted cyclohexanones and 3-methylcyclopentanone failed and it was even found that benzaldehyde deactivated the enzyme. 

Commercial acetone cyanohydrin (Aldrich Chemical Company, Inc.) was used without further purification. 

Xu, L.L., Singh, B.K. and Conn, E.E. (1988) Purification and characterization of acetone cyanohydrin lyase from Linum usitatissimum. Arch. Biochem. Biophys., 263, 256-64. 

Acetone, CH3COCH3, [1, 5, before Acetone cyanohydrin]. Mol. wt. 58.05, b.p. 56-57°. For commercial sources of pure acetone, see 1. 1110. For the purification of reagent required for the preparation of carbohydrate acetonides, Whistler and Wolfrom1 recommend that technical-grade acetone be refluxed with small amounts of permanganate until the purple color persists, distilled, and dried for 2 days over anhydrous potassium carbonate or calcium sulfate, filtered, and distilled. 

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