Methyl ester sulphonates

Horie, K. (2004) New process of methyl ester sulphonate and its application. Proceedings 6th World... 

The sulphonates derived from fatty acid alkyl esters (mainly, as sodium salts of a-sulphomonocarboxylic esters or, in other words, methyl ester sulphonates) become more and more attractive in view of their renewable raw material sources, such as triglycerides of animal and vegetable origin. Fatty acid alkyl esters are produced via a direct transesterification of triglycerides with alcohol, typically methanol, or via direct esterification of fatty acids. The same thin-film sulphonation techniques (see Table 1.5) with gaseous SO3 are used today to manufacture these surfactants [62, 70]. The two-step sulphonation can be represented by the sequential reactions [70, 71] shown in Fig. 1.4. 

FAME may become in the future a possible organic feedstock to be sulphonated to Fatty Acid Methyl Ester Sulphonate (FAMES). This feedstock is naturally renewable as it is produced from oils/fats or fatty acids. There are several possible process routes for the manufacture of FAME. Transesterification of fat triglycerides is the predominant method for manufacture of mixed fatty acid methyl esters, and direct esterification of fatty acids (FA) is practised if very selective cuts of product, in general as an intermediate detergent range alcohol, are desired. Methyl cocoate is a mobile, oily liquid above 25"C with a yellow tint and a characteristic fatty acid pungent odour. FAME sulphonation to FAMES is technically possible but hardly applied up to now (1990). 

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. 

Hydrogen peroxide may be used as a bleaching agent in fatty acid methyl ester sulphonation. 

Thus, if a mole ratio of about 1.2 1 of SO3 to ester is used, the initial reaction gives about 50% conversion of starting material, the products being intermediates I and II. On ageing, these intermediates release SO3, which reacts with the remaining ester, and the final product is a mixture of FAMES acid (FAMES = Fatty Acid Methyl Ester Sulphonate) and SFAS acid (SFAS = Sulphonated Fatty Acid Sodium salt, RCH-COONa). 

Fatty acid methyl ester sulphonates quality... 

FAME-SA Fatty Acid Methyl Ester - Sulphonic... 

FAMES Fatty Acid Methyl Ester Sulphonate... 

Base-induced elimination of sulphinate from homoallylic sulphones , from y-ketosulphones , and from 1,2-bissulphones has been used in synthetic sequences ranging from the preparation of retinoic acid and of its methyl ester , to a novel pentannulation sequence that leads to a range of cross-conjugated dienes , as exemplified by equation (69). The overall yield for the two steps was 63%. 

Solid esters are easily crystallisable materials. It is important to note that esters of alcohols must be recrystallised either from non-hydroxylic solvents (e.g. toluene) or from the alcohol from which the ester is derived. Thus methyl esters should be crystallised from methanol or methanol/toluene, but not from ethanol, n-butanol or other alcohols, in order to avoid alcohol exchange and contamination of the ester with a second ester. Useful solvents for crystallisation are the corresponding alcohols or aqueous alcohols, toluene, toluene/petroleum ether, and chloroform (ethanol-free)/toluene. Carboxylic acid esters derived from phenols are more difficult to hydrolyse and exchange, hence any alcoholic solvent can be used freely. Sulphonic acid esters of phenols are even more resistant to hydrolysis they can safely be crystallised not only from the above solvents but also from acetic acid, aqueous acetic acid or boiling n-butanol. 

A recent procedure for the preparation of methyl esters involves refluxing the carboxylic acid with methanol and 2,2-dimethoxypropane in the presence of toluene-p-sulphonic acid as the catalyst (Expt 5.146). The water produced in the esterification process is effectively removed by acid-catalysed reaction with the ketal to give acetone and methanol. 

As a class of surfactant, sulphonated methyl esters (SMEs) have been known since the 1980s, but have not been widely commercialised. Through the late 1990s into 2000, there were signs of increased use in Asia and the United States across a variety of applications. They share many similarities with olefin sulphonates but, importantly, they are made from renewable oleochemical feedstocks. This is preferred by many formulators, particularly in cosmetic and personal care applications. 

Chemistry and general properties. The product is prepared by reacting a fatty acid, typically oleic acid (a 08 1 acid), with oleum, or preferably sulphur trioxide. If a saturated fatty acid is used, the product is an a-sulphofatty acid, R(S03H)C00H and the reaction mechanism is thought to be similar to that previously suggested for the sulphonation of methyl esters. With the use of an unsaturated acid, such as oleic, the picture becomes more complex. The reaction chemistry is not fully understood, but the product is a mixture of y-hydroxy sulpho fatty acid and o -sulphonated oleic acid. 

Raw materials. It is possible to use any fatty acid as a feed material for sulphonation but economic considerations dictate that oleochemical material be preferred. Fatty acids are readily obtained from vegetable and animal oils and fats which are fatty acid triglycerides. These are transesterified to generate glycerol and three moles of a fatty acid ester, normally a methyl ester. The methyl ester can be distilled to give a specific cut and the fatty acid finally isolated by hydrolysis or hydrogenation of the ester. It is common to use animal fats (tallow) in which case the dominant C chains are 16 and 18. 

METHYL ESTER STEARIC ACID see MJWOOO METHYL ESTER of WOOD ROSIN see MFT500 METHYL ESTER of WOOD ROSIN, partially hydrogenated (FCC) see MFT500 METHYLE (SULFATE de) (FRENCH) see DUDIOO 4,4 - (1 -METHYL-1,2-ETHANEDIYL)BIS-2,6-PIPERAZINEDIONE see PIK250 METHYL ETHrVNE SULFONATE see MJW250 METHYL ETHANE SULPHONATE see MJW250... 

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. 

On heating the 2-yS-azidomethyl penam sulphone (85) with suitable acetylenes, a series of 2-/S-(l,2,3-triazolyl)methyl penam sulphone esters was obtained, which upon deprotection gave the free acids (86) [48, 49]. In particular, reaction of (85) with either vinyl acetate or (trimethylsi-lyl)acetylene provided the parent triazole, tazobactam (30), after hydrogenation (and prior potassium fluoride-18-crown-6 treatment in the case of the TMS acetylene) [50]. 

Esters, Carboxylic Acids, and Ethers.—The rates of hydrolysis of 3(3- and 6(3-acetoxy-4 ,5 -epoxides and 1 a-acetoxy-2(3,3 (3-epoxides were observed to be accelerated relative to those acetates not containing a neighbouring epoxide group.24 Bile acid methyl esters were readily prepared from the carboxylic acids by reaction with methanol in the presence of toluene-p-sulphonic acid.25 Bile acids were readily converted into the amino-amides (14) by successive reaction with Bu N-... 

The latter was converted via the alcohol, toluene-p-sulphonate, and nitrile to homodaphniphyllic acid. Its methyl ester (164) was subsequently found as a natural product. ... 

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