- Biomass-derived dibasic acids to diesters with inorganic ligand-supported catalyst: synthesis, optimization, characterization
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Several attempts have been made to obtain aliphatic dicarboxylic diesters from esterification reaction to develop the biomass-derived platform molecules and green manufacturing processes. In this paper, Na3(H2O)6[AlMo6O18(OH)6], an Anderson-type polyoxometalate, firstly, was reported as a catalyst for diester synthesis from dicarboxylic acid to diester which showed an well productivity and selectivity characterized by 1H and 13C. Response surface methodology (RSM) integrated with the desirability function approach was used to determine the best operative conditions, and the optimal reaction parameters for maximum dipropyl succinate yield (77 ± 2.5%) were identified as 1.19?mol.% catalyst loading, 4.9:1 propanol/succinic acid ratio, 113?°C, and 9.6?h. Three batches of tests were carried for catalyst recycling with 78–75% yield even after 6 cycles of esterification. In addition, the substrate carbon chain was increased for investigation of substrate scope achieving satisfactory results and all products were characterized by 1H and 13C nuclear magnetic resonance spectroscopy.
- Chen, Zhe,Han, Sheng,Lu, Deli,Xu, Yumeng
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- Mono-substitution of symmetric diesters: Selectivity of: Mycobacterium smegmatis acyltransferase variants
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A method for selectively reacting one, out of two identical carboxylic esters in a symmetric diester has been developed. An esterase from Mycobacterium smegmatis (MsAcT) has a restricted active site resulting in a narrow acyl donor specificity. This constraint was used to develop a selective synthesis route from divinyl adipate (a symmetric diester) towards mixed vinyl adipate esters. To find a suitable catalyst, the wild type (wt) MsAcT and two MsAcT variants: A single point mutant (L12A) and a double point mutant (T93A/F154A), were immobilized and studied under solvent-free conditions. Out of the tested catalysts, MsAcT L12A was the most selective for mono-Transesterification of divinyl adipate. When divinyl adipate was reacted with 1.5 equivalents of a hydroxyl vinyl ether full conversion of DVA was observed yielding over 95% mixed diester. Furthermore, the limitations for longer dicarboxylic esters were studied, showing that MsAcT T93A/F154A tolerated up to at least dimethyl sebacate.
- Finnveden, Maja,Semlitsch, Stefan,He, Oscar,Martinelle, Mats
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p. 4920 - 4927
(2019/10/05)
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- SKIN EXTERNAL PREPARATIONS AND COSMETICS
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An object of the present invention is to provide skin external preparations and cosmetics which contain a branched acyl carnitine and have excellent formulation stability. A skin external preparation of the present invention includes a carnitine derivative represented by the following Formula (1) and/or a carnitine derivative salt represented by the following Formula (2), and an amphoteric surfactant. In Formula (1), R1 and R2 are each independently a C1-18 optionally branched, saturated or unsaturated aliphatic hydrocarbon group. In Formula (2), R1 and R2 are the same as in Formula (1), X? is a specific anion and Y+ is a specific cation.
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- Cosmetic composition
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A composition suitable for topical application to mammalian skin or hair for inducing, maintaining or increasing hair growth comprises: (i) a first chemical inhibitor chosen from proteoglycanase inhibitors, glycosaminoglycanase inhibitors, glycosaminoglycan chain cellular uptake inhibitors or mixtures thereof; and (ii) a cosmetically acceptable vehicle for the chemical inhibitor; provided that when the first chemical inhibitor is a weak inhibitor, such that a 1 mM aqueous solution of the inhibitor reduces proteoglycanase activity, glycosaminoglycanase activity or cellular uptake of glycosaminoglycan chains, by from 5 to 50%, in accordance with at least one of the assay tests as herein described, then there is also present in the composition a second chemical inhibitor and/or an activity enhancer. When minoxidil is the sole chemical inhibitor, then the activity enhancer is a penetration enhancer chosen from a limited number of materials, including certain esters and cationic polymers. The total amount of chemical inhibitor present in the composition is sufficient to increase hair growth in the rat, when said composition is applied topically thereto, by at least 10% more than that obtainable using a control composition from which the said inhibitors have been omitted.
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