- Efficient esterification of long chain aliphatic carboxylic acids with alcohols over ZrOCl2·8H2O catalyst
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Direct condensation of equimolar amounts of long chain carboxylic acids and alcohols could be achieved by using zirconyl chloride as an efficient catalyst. ZrOCl2·SH2O showed high activity for esterification between primary acids and alcohols; however, it was less active in the combination of branched acid and secondary alcohols to give the corresponding esters. Georg Thieme Verlag Stuttgart.
- Mantri, Kshudiram,Komura, Kenichi,Sugi, Yoshihiro
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- Protic acid immobilized on solid support as an extremely efficient recyclable catalyst system for a direct and atom economical esterification of carboxylic acids with alcohols
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(Chemical Equation Presented) A convenient and clean procedure of esterification is reported by direct condensation of equimolar amounts of carboxylic acids with alcohols catalyzed by an easy to prepare catalyst system of perchloric acid immobilized on silica gel (HClO4-SiO2). The direct condensation of aryl, heteroaryl, styryl, aryl alkyl, alkyl, cycloalkyl, and long-chain aliphatic carboxylic acids with primary/secondary alkyl/cycloalkyl, allyl, propargyl, and long-chain aliphatic alcohols has been achieved to afford the corresponding esters in excellent yields. Chiral alcohol and N-t-Boc protected chiral amino acid also resulted in ester formation with the representative carboxylic acid or alcohol without competitive N-t-Boc deprotection and detrimental effect on the optical purity of the product demonstrating the mildness and chemoselectivity of the procedure. The esters of long-chain (>C10) acids and alcohols are obtained in high yields. The catalyst is recovered and recycled without significant loss of activity. The industrial application of the esterification process is demonstrated by the synthesis of prodrugs of ibuprofen and a few commercial flavoring agents. Other protic acids such as H2SO4, HBr, TfOH, HBF4, and TFA that were adsorbed on silica gel were less effective compared to HClO4-SiO2 following the order HClO4-SiO 2 ? H2SO4-SiO2 > HBr-SiO 2 > TfOH-SiO2 ? HBF4-SiO2 ≈ TFA-SiO2. When HClO4 was immobilized on other solid supports the catalytic efficiency followed the order HClO4-SiO 2 > HClO4-K10 > HClO4-Al 2O3 (neutral) > HClO4-Al2O 3 (acidic) > HClO4-Al2O3 (basic).
- Chakraborti, Asit K.,Singh, Bavneet,Chankeshwara, Sunay V.,Patel, Alpesh R.
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supporting information; experimental part
p. 5967 - 5974
(2009/12/24)
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- Liquid-liquid biphasic synthesis of long chain wax esters using the Lewis acidic ionic liquid choline chloride·2ZnCl2
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The first liquid-liquid biphasic synthesis of wax esters in a Lewis acidic ionic liquid, choline chloride·2ZnCl2 by the esterification of long chain carboxylic acids with long chain alcohols is described. The reported reaction system has the advantages of both homogeneous and heterogeneous catalysis with high product yield and the ease of product as well as catalyst separation without the use of an organic solvent. The ionic liquid studied plays the dual role of solvent as well as catalyst and is recycled up to six times without any significant loss of activity.
- Sunitha, Sadula,Kanjilal, Sanjit,Reddy, P. Srinivasa,Prasad, Rachapudi B.N.
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p. 6962 - 6965
(2008/02/13)
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- PROCESS FOR PRODUCING CARBOXYLIC ACID ESTER AND ESTERIFICATION CATALYST
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A process for carboxylic acid ester production by which a carboxylic acid ester comprising an alcohol and a carboxylic acid each having 10 or more carbon atoms can be produced in a high yield. The catalyst used can be reused. The process generates a small amount of wastes and is less apt to pose an environmental problem. Also provided is an esterification catalyst usable in the process. In the esterification of a C10 or higher carboxylic acid and a C10 or higher alcohol, use is made, as a catalyst, of a hydrate of a salt of at least one metal selected among aluminum, gallium, indium, iron, cobalt, nickel, zinc, zirconium, hafnium, and niobium.
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Page/Page column 21-22
(2008/06/13)
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- Lip treatment composition
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A lip-treatment composition for topical application to the lips comprising a base comprising oil, water and a structurant, and at least one active component active with regard to the lips, gums, teeth, throat, or oral mucosa.
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