Employing lipase of candida antarctica (calb) as catalyst in the acetylation of para-aminophenol in aqueous and water-free medium

Candida antarctica lipase B (CaLB) is one of lipase classes enzymes that has many advantages to be used in the process of synthesizing organic compounds. In this study, some experiments were conducted to examine the ability of CaLB as a catalyst in the para-aminophenol (PAP) acetylation to produce paracetamol as the result. Two types of research have been carried out, the first one is to utilize CaLB to catalyze acetylation of PAP in a water-free reaction medium, and the second one is to use CaLB as catalyst in aqueous medium through oxidative amidation reaction. Reaction in water free system was held in ethyl catalyst acetate as solvent that also act as the acyl donor, while in the aqueous medium, acetylacetone was used as acyl donor and ethyl acetate as source to produce peracid that will be used as oxidator. Analysis was done by HPLC and TLC densitometric to follow the amount of paracetamol produced. The results of CaLB-catalyzed acylation in water free system showed that the enzyme could accept PAF and ethyl acetate as a substrate in a nucleophilic substitution reaction, resulting in paracetamol as a product. However, the yield from the acylation of PAP is still not satisfactory. In the reaction in aqueous medium, CaLB has been proven to show its activity to catalyze the acylation of PAP with acetylacetone, as well as the reaction of peracid formation from ethyl acetate. The results show that this strategy can work well and give better yields than the other reaction in water-free medium.

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Synthesis of geranyl acetate by transesterification of geraniol with ethyl acetate over Candida antarctica lipase as catalyst in solvent‐free system

Flavour and Fragrance Journal ◽

10.1002/ffj.3502 ◽

2019 ◽

Vol 34 (4) ◽

pp. 288-293 ◽

Cited By ~ 3

Author(s):

Kalpesh V. Bhavsar ◽

Ganapati D. Yadav

Keyword(s):

Ethyl Acetate ◽

Candida Antarctica ◽

Solvent Free ◽

Geranyl Acetate ◽

Candida Antarctica Lipase ◽

Free System ◽

Solvent Free System

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IMMOBILIZED LIPASES AS BIOCATALYSTS FOR ORGANIC SYNTHESIS 1. TRANSESTERIFICATION OF ETHYL ACETATE WITH ALCOHOLS IN THE PRESENCE OF FREE Candida antarctica LIPASE B

Environmental Engineering and Management Journal ◽

10.30638/eemj.2005.040 ◽

2005 ◽

Vol 4 (4) ◽

pp. 449-462

Author(s):

Brindusa Dragoi ◽

Emil Dumitriu

Keyword(s):

Ethyl Acetate ◽

Organic Synthesis ◽

Candida Antarctica ◽

Candida Antarctica Lipase B ◽

Candida Antarctica Lipase ◽

Lipase B ◽

Immobilized Lipases

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Chlorination of 2,4,6-trichlorophenol in acidic aqueous medium

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19851842 ◽

1985 ◽

Vol 50 (8) ◽

pp. 1842-1851 ◽

Cited By ~ 1

Author(s):

Petr Švec

Keyword(s):

Reaction Mechanism ◽

Aqueous Medium ◽

Hydrogen Chloride ◽

Reaction Medium ◽

Model Experiments ◽

Sulfuric And Hydrochloric Acids

The course of chlorination of 2,4,6-trichlorophenol (I) in water and approximately 20% sulfuric and hydrochloric acids has been investigated. In all these media the reaction gives primarily 2,4,6,6-tetrachloro-2,4-cyclohexadienone (II) which is subsequently chlorinated under formation of polychlorinated alicyclic ketones or isomerized to give the more stable 2,4,6,6-tetrachloro-2,5-cyclohexadienone (III), the precursor of further arising chlorinated 1,4-benzoquinones. The ratio of the arising polychlorinated alicyclic ketones to chlorinated 1,4-benzoquinones is significantly influenced by concentration of hydrogen chloride in the reaction medium. On the basis of model experiments, the reaction mechanism of exhaustive chlorination of 2,4,6-trichlorophenol has been suggested.

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Polymer structure and catalytic activity of ion exchangers

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19811577 ◽

1981 ◽

Vol 46 (7) ◽

pp. 1577-1587 ◽

Cited By ~ 8

Author(s):

Karel Jeřábek

Keyword(s):

Catalytic Activity ◽

Ethyl Acetate ◽

Active Sites ◽

Crosslinking Agent ◽

Reaction Medium ◽

Polymer Structure ◽

Local Concentration ◽

Ion Exchangers ◽

Styrene Divinylbenzene ◽

Kinetics Of

Catalytic activity of ion exchangers prepared by partial sulphonation of styrene-divinylbenzene copolymers in reesterifications of ethyl acetate by methanol and propanol, hydrolysis of ethyl acetate and in synthesis of bisphenol A has been compared with data on polymer structure of these catalysts and with distribution of the crosslinking agent, divinylbenzene, calculated from literature data on kinetics of copolymerisation of styrene with divinylbenzene. It was found that the polymer structure of ion exchangers influences catalytic activity predominantly by changing the local concentration of acid active sites. The results obtained indicated that the effect of transport phenomena on the rate of catalytic reactions does not depend on the degree of swelling of the ion exchangers in reaction medium but it is mainly dependent on the relative affinity of reaction components to the acid groups or to the polymer skeleton.

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ChemInform Abstract: Candida antarctica Lipase B Catalyzed Synthesis of Acetamides Using [BMIm(PF6)] as a Reaction Medium.

ChemInform ◽

10.1002/chin.200938049 ◽

2009 ◽

Vol 40 (38) ◽

Author(s):

Kishor P. Dhake ◽

Ziyauddin S. Qureshi ◽

Rekha S. Singhal ◽

Bhalchandra M. Bhanage

Keyword(s):

Reaction Medium ◽

Candida Antarctica ◽

Candida Antarctica Lipase B ◽

Candida Antarctica Lipase ◽

Lipase B

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Enzymatic synthesis and application of fatty acid ascorbyl esters

Hemijska industrija ◽

10.2298/hemind120522079s ◽

2013 ◽

Vol 67 (2) ◽

pp. 239-247 ◽

Cited By ~ 2

Author(s):

Marija Stojanovic ◽

Milica Carevic ◽

Mladen Mihailovic ◽

Zorica Knezevic-Jugovic ◽

Slobodan Petrovic ◽

...

Keyword(s):

Fatty Acid ◽

Vitamin C ◽

Organic Solvents ◽

Molecular Sieves ◽

Reaction Medium ◽

Log P ◽

Acyl Donor ◽

Vinyl Esters ◽

Ascorbyl Esters ◽

Acyl Donors

Fatty acid ascorbyl esters are liposoluble substances that possess good antioxidative properties. These compounds could be synthesized by using various acyl donors for acylation of vitamin C in reaction catalyzed by chemical means or lipases. Enzymatic process is preferred since it is regioselective, performed under mild reaction conditions, with the obtained product being environmentally friendly. Polar organic solvents, ionic liquids, and supercritical fluids has been successfully used as a reaction medium, since commonly used solvents with high Log P values are inapplicable due to ascorbic acid high polarity. Acylation of vitamin C using fatty acids, their methyl-, ethyl-, and vinyl esters, as well as triglycerides has been performed, whereas application of the activated acyl donors enabled higher molar conversions. In each case, majority of authors reported that using excessive amount of the acyl donor had positive effect on yield of product. Furthermore, several strategies have been employed for shifting the equilibrium towards the product by water content control. These include adjusting the initial water activity by pre-equilibration of reaction mixture, enzyme preparation with water vapor of saturated salt solutions, and the removal of formed water by the addition of molecular sieves or salt hydrate pairs. The aim of this article is to provide a brief overview of the procedures described so far for the lipase-catalyzed synthesis of fatty acid ascorbyl esters with emphasis on the potential application in food, cosmetics, and pharmaceutics. Furthermore, it has been pointed out that the main obstacles for process commercialization are long reaction times, lack of adequate purification methods, and high costs of lipases. Thus, future challenges in this area are testing new catalysts, developing continuous processes for esters production, finding cheaper acyl donors and reaction mediums, as well as identifying standard procedures for purification of products which will not require consumption of large amounts of non-biocompatible organic solvents.

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