- Efficient Enzymatic Preparation of Flavor Esters in Water
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A straightforward biocatalytic method for the enzymatic preparation of different flavor esters starting from primary alcohols (e.g., isoamyl, n-hexyl, geranyl, cinnamyl, 2-phenethyl, and benzyl alcohols) and naturally available ethyl esters (e.g., formate, acetate, propionate, and butyrate) was developed. The biotransformations are catalyzed by an acyltransferase from Mycobacterium smegmatis (MsAcT) and proceeded with excellent yields (80-97%) and short reaction times (30-120 min), even when high substrate concentrations (up to 0.5 M) were used. This enzymatic strategy represents an efficient alternative to the application of lipases in organic solvents and a significant improvement compared with already known methods in terms of reduced use of organic solvents, paving the way to sustainable and efficient preparation of natural flavoring agents.
- Perdomo, Igor Chiarelli,Gianolio, Stefania,Pinto, Andrea,Romano, Diego,Contente, Martina Letizia,Paradisi, Francesca,Molinari, Francesco
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p. 6517 - 6522
(2019/06/20)
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- Method for synthesizing propionate through ester-ester exchange path
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The invention provides a method for synthesizing propionate through an ester-ester exchange path and relates to a method for synthesizing the propionate. According to the method, reaction raw materials include, but are not limited to ethyl formate, propyl formate, butyl formate, ethyl acetate, propyl acetate, butyl acetate and the like; the method for synthesizing the propionate through an ester exchange one-step method is adopted. A catalyst comprises alkaline materials including ionic liquid, soluble strong base, solid base and the like respectively; the catalyst has the advantages of high catalysis efficiency and no pollution. By taking methyl propionate and ethyl acetate reaction as an example, KOH is used as the catalyst, the mol ratio of the raw materials is 1 to 1, the reaction temperature is 60 DEG C and the reaction time is 5 min; the conversion ratios of the methyl propionate and the ethyl acetate can reach 70 percent or more; products comprise ethyl propionate and the methylacetate. The whole reaction path has the characteristics of short synthetic route, simple technological flow and high yield and the catalyst is stable, does not become inactive and can be repeatedlyutilized.
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Paragraph 0030-0031
(2019/04/04)
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- A clean enzymatic process for producing flavour esters by direct esterification in switchable ionic liquid/solid phases
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A clean biocatalytic approach for producing flavour esters using switchable ionic liquid/solid phases as reaction/separation media has been developed. The phase behaviour of different IL/flavour acetyl ester (geranyl acetate, citronellyl acetate, neryl acetate and isoamyl acetate) mixtures was studied at several concentrations, resulting for all cases in fully homogeneous liquid media at 50 °C, and solid systems at room temperature. By using an iterative centrifugation protocol on the solid IL/flavour ester mixtures at controlled temperatures, the solid IL phase and the liquid flavour ester phase can be easily separated. The excellent suitability of an immobilized Candida antarctica lipase B (Novozym 435) catalyst in the esterification reaction between an aliphatic carboxylic acid (acetic, propionic, butyric or valeric) and a flavour alcohol (isoamyl alcohol, nerol, citronellol or geraniol) in N,N′,N′′,N′′′-hexadecyltrimethyl-ammonium bis(trifluoromethylsulfonyl)imide ([C16tma][NTf2])IL has been demonstrated, the product yield being improved up to 100% under appropriate reaction conditions (enzyme amount, dehydrating molecular sieves, etc.) at 50 °C. The enzymatic synthesis of sixteen different flavour esters was carried out in [C16tma][NTf2] by means of this approach, providing products of up to 0.757 g mL-1 concentration after IL separation. The residual activity of the enzyme/IL system during seven consecutive operation cycles was shown to be practically unchanged after reuse.
- Lozano, Pedro,Bernal, Juana M.,Navarro, Alicia
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p. 3026 - 3033
(2013/01/15)
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- PROCESS FOR PRODUCTION OF DIALKYLTIN DIALKOXIDES
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An object of the present invention is to provide a process for producing a dialkyl tin compound from a composition of deactivated forms of a dialkyl tin catalyst, and to provide a process for producing the dialkyl tin catalyst from the dialkyl tin compound and using the dialkyl tin catalyst to produce a carbonic acid ester. According to the present invention, a process for producing a dialkyl tin compound is provided that subjects a composition of the deactivated forms of the dialkyl tin catalyst, formed when producing an ester compound, to an alkyl group redistribution reaction and/or dealkylation reaction.
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Page/Page column 43
(2009/07/25)
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- Solid acids in liquid phase esterification
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Catalytic activity of different protonated zeolites such as HY, Hβ, HZSM5 and sulfated oxides such as SO42-/Al 2O3, SO42-/SiO2, SO 42-/ZrO2 in the esterification of propionic acid with various alcohols (C1-C5) over solid acids as catalysts has been investigated. The catalysts have been characterized for their total surface acidity, BET surface area and sulfur content in sulfated catalysts. Catalytic activity studies have been conducted in liquid phase under refluxing conditions. A systematic study has been made to find out the effects of nature of alcohols, amount of the catalyst and the duration of reaction in the synthesis of propionate esters. Product analysis has been done quantitatively by gas chromatography and qualitatively by GC-MS. All the catalysts have been found to be active towards the formation of propionate esters as the major reaction product. A good correlation between the concentration of acid sites and the catalytic activity of the catalysts has been observed.
- Nagaraju,Mohamed Shamshuddin
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p. 1165 - 1170
(2007/10/03)
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- Esterification of isoamyl alcohol using solid acid catalysts
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Catalytic activity of different solid acids obtained by calcination of hydroxides of Al, Si, Zr and Ti as well as their sulfated forms has been investigated in liquid phase esterification of isoamyl alcohol with propionic acid. The catalysts have been characterized for their textural properties, surface acidity, surface area and sulfur content. The major product of the catalytic reaction has been found to be isoamyl propionate. The yield (%) of the ester has been found to depend on the textural properties, total surface acidity and surface area of the catalysts. In the case of sulfated zirconia which exhibited highest acidity, isoamyl ether has also been formed to an extent of 0.6-4.5%. Effects of amount of catalyst, duration of the reaction and the molar ratios of the reactants on the yield of ester have been studied. A plausible reaction mechanism for the formation of isoamyl propionate is described.
- Nagaraju,Shamshuddin, S. Z. Mohamed
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p. 2060 - 2065
(2007/10/03)
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- Catalytic esterifications of carboxylic acids and alcohols by sodium bisulfate monohydrate
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The efficient esterification of primary and secondary alcohols with aliphatic carboxylic acids in the presence of a catalytic amount of sodium bisulfate monohydrate to afford the corresponding esters in high yields.
- Li, Yi-Qun
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p. 3901 - 3903
(2007/10/03)
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- Preparation of salicylic acid resin supported FeCl3 lewis acid catalyst and its application in organic synthesis
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The catalytic effects of salicylic acid resin supported FeCl3 catalyst on the esterification of alcohol and carboxylic acid and on the acetalization (ketal formation) of aldehyde (ketone) and alcohol have been investigated.This catalyst is convenient to use, noncorrosive, easy to be separated from reactants and can be repeatedly used.
- Huirong, Yang,Yingde, Li Bina Cui
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p. 1233 - 1238
(2007/10/03)
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- A study on synthesis of esters by superacid resin catalysts
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Superacid resin as catalyst, instead of the strong acid cation exchange resin and sulfuric acid was used to synthesis n-butyl lactate. Some factors affection reaction, such as time, moles ratio of reactants and catalyst amount were studied. Results made known that time was shorten very much. Under our optimum conditions the ester yield was over 99.5%. In the other hand, superacid resin as catalyst was used to synthesis other esters, had result of raise ester yield and shorten the time of esterification.
- Yang,Li,Fang
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p. 3269 - 3275
(2007/10/02)
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