Sulphonate esters iodination

Distilled fatty methyl esters with low iodine values are used as the starting raw material for the production of SME. The fatty methyl ester is first reacted with sulfur trioxide at 80-90°C in a falling-film reactor. The dark product obtained from this process is bleached using hydrogen peroxide. After bleaching, the lighter color product is neutralized with alkali to produce an a-sulphonated methyl ester. 

Peroxy acids are useful oxidizing agents and are generally analysed on the basis of their ability to oxidize iodide ion to iodine which can be determined titrimetrically or colorimetrically. They also oxidize alkenes to epoxides, ketones to esters or lactones, thioethers to sulphoxides and sulphones, and tertiary amines to amine oxides. 

One of the most important requirements to produce quality methyl ester sulphonate is the use of a high quality methyl ester feedstock. The best of the feedstocks currently used are highly refined palm oil derivatives. These feedstocks have low acid values, a narrow molecular weight distribution, contain little or no paraffinic compounds and have been extensively hydrogenated to reduce their iodine value to a very low value (less than 0.5). The latter is essential because high iodine values indicate the presence of double bonds in the feedstock which will result in dark coloured products upon sulphonation. 

Cyclization of the unsaturated epoxy-ester (100), to a-pyrone (101), has been effected using iodine and toluene-p-sulphonic acid in benzene. ... 

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