Problem statement: Acetol is used as organic intermediates because it contains both hydroxyl and carbonyl functional groups and mainly use to produce polyols and acrolein. It also widely uses as reduced dyes and skin tanning agent. The commercially used acetol is made from petroleum-based that leads to high cost of production. Approach: This review highlighted applications of acetol and established methods and factors affecting acetol selectivity. Global market of acetol and its contribution in Malaysia were also surveyed. Results: Multiple ways which was through dehydration of glycerol or dehydrogenation of polyols and sugar alcohols could be applied to produce acetol. Conclusion: The approach using glycerol as feedstock since its economic viable in the presence of metal supported acidic catalyst is the very promising and reliable because it's high conversion and selectivity. The production under optimum conditions still remained as an open challenge to all researchers.

Dihydroxystearic acid (DHSA) ester was synthesized enzymatically to overcome the problems associated with chemical processes. Immobilized enzyme, Lipozyme IM and Novozym 435, were employed as catalysts in the esterification reaction between DHSA and monohydric alcohol. Various factors that may affect the esterification reaction were studied, such as initial water content (a w ), organic solvent, substrate concentration and the influence of alcohol chain length. It was found that the percent conversion was higher in organic solvents with log P (the logarithm of the partition coefficient of solvent in octanol/water system) from 2.0 to 4.0. The reaction was not affected by a w from 0.09 to 0.96. Increasing the mole ratio of alcohol to acid above 2.0 did not increase the percent conversion of ester. The ester was identified by Fourier transform infrared and 13 C nuclear magnetic resonance spectroscopy.Hydroxy fatty acid esters are of considerable industrial interest compared with ordinary esters because of their different behaviors including solubility, surface-active properties, and thermal stability (1). These compounds have interesting applications, such as plasticizers, mold release agent, waxes, surfactant and chemical intermediates (2). Sulfonated wax esters of ricinoleic acid are promising surface-active compounds (3). Current manufacture of these esters is realized by reacting a fatty acid/hydroxy fatty acid and an alcohol at high temperature in the presence of a tin, titanium, or sulfuric acid catalyst for up 20 h. This high-temperature process can lead to degradation of the ester and undesired side reactions; additionally, the resulting energy costs are high (4).Lipase-catalyzed reactions operate at mild conditions, which prevent degradation of starting materials and reduce side reactions. Application of lipases in various biochemical modifications of fats and oils is well established, and the catalytic activity of lipases toward hydroxy acids is also well studied by various workers (4-7). For example, Rhizomucor miehei lipase has been employed in the esterification of 12-hydroxystearic acid and alcohol (4). Mukesh et al. (5) have produced ricinoleic acid wax esters by R. miehei lipase-catalyzed esterification of ricinoleic acid or alcoholysis of castor oil. Wagner et al. (6) and Hayes (7) also employed R. miehei to prepare wax ester by esterification or alcoholysis reactions.The aims of the present study are to investigate the enzymatic esterification reaction of the carboxyl group of dihydroxystearic acid (DHSA) with monohydric alcohol (Scheme 1) and to examine the effect of various reaction parameters. MATERIALS AND METHODSMaterials. DHSA was prepared in the laboratory (8). 1-Octanol (purity, 99%) and 1-octadecanol (purity, 99%) were purchased from Sigma Chemical Co. (St. Louis, MO). 1-Decanol (purity, 98%), 1-dodecanol (purity, 98%), 1-tetradecanol (purity, 98%), and 1-hexadecanol (purity, >95%) were from Merck (Darmstadt, Germany). Lipozyme IM (lipase from R. miehei) and Novozym 435 (lipase from Candid...

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Dihydroxystearic acid (DHSA) was prepared from palm oleic acid and characterized by chromatographic and spectroscopic methods (gas chromatography, thin-layer chromatography, Fourier transform infrared and nuclear magnetic resonance spectroscopy) as well as wet chemistry. The crude product has a melting point of 62°C, acid value of 179, saponification value of 178, and hydroxyl value of 196. The yield was about 90% based on unsaturation. The product obtained was found to contain DHSA, saturated fatty acids, and unknown products. DHSA is soluble in alcohol, and its solubility decreased by increasing the alcohol chain length. An irritancy test of DHSA indicated that purified DHSA is nonirritating.

The esterification of palm-based 9,10-dihydroxystearic acid (DHSA) and 1-octanol in hexane as catalyzed by lipase from Rhizomucor meihei (Lipozyme IM) followed Michaelis-Menten kinetics. The esterification reaction follows a Ping-Pong, Bi-Bi mechanism. The maximum rate was estimated to be 1 micromol min(-1) mg(-1) catalyst in hexane at 50 degrees C, and the Michaelis-Menten constants for DHSA and 1-octanol were 1.3 M and 0.7 M, respectively.