Xi:Irritant;53571-83-8Relevant articles and documents
Dialkyl 3,3′-thiodipropionate and dialkyl 2,2′-thiodiacetate antioxidants by lipase-catalyzed esterification and transesterification
Weber, Nikolaus,Klein, Erika,Vosmann, Klaus
, p. 2957 - 2963 (2007/10/03)
Medium- and long-chain dialkyl 3,3′-thiodipropionate antioxidants such as dioctyl 3,3′-thiodipropionate, didodecyl 3,3′- thiodipropionate, dihexadecyl 3,3′-thiodipropionate, and di-(cis-9-octadecenyl) 3,3′-thiodipropionate were prepared in high yield by lipase-catalyzed esterification and transesterification of 3,3′-thiodipropionic acid and its dimethyl ester, respectively, with the corresponding medium- or long-chain 1-alkanols, i.e., 1-octanol, 1-dodecanol, 1-hexadecanol, and cis-9-octadecen-1-ol, in vacuo (80 kPa) at moderate temperatures (60-80°C) without solvents. Immobilized lipase B from Candida antarctica (Novozym 435) was the most active biocatalyst for the preparation of medium- and long-chain dialkyl 3,3′-thiodipropionates showing enzyme activities up to 1489 units/g, whereas the immobilized lipases from Rhizomucor miehei (Lipozyme RM IM) and Thermomyces lanuginosus (Lipozyme TL IM) were by far less active (～10 enzyme units/g). Maximum conversions to dialkyl 3,3′-thiodipropionates were as high as 92-98% after 4 h of reaction time. Similarly, dihexadecyl 2,2′-thiodiacetate was prepared in high yield using 2,2′-thiodiacetic acid or diethyl 2,2′-thiodiacetate and 1-hexadecanol as the starting materials and Novozym 435 as the biocatalyst.
Stabilizer for synthetic resins
-
, (2008/06/13)
Synthetic resins, particularly polyolefins, are markedly improved in their resistances to heat and oxidation by the incorporation of a 2-methyl-4-t-butyl-5-hydroxyphenylalkanoic acid ester alone or in combination with a thioether-type antioxidant represented by the general formula STR1 wherein R represents an alkyl group of 12 to 20 carbon atoms, or by the general formula STR2 wherein R represents an alkyl group of 4 to 20 carbon atoms.
