Search results

1

The influence of the catalyst on the kinetics of ethyl metacrylate synthesis

100%

Grzesik M., Witczak T.

Polish Journal of Chemical Technology

|

2007

|

vol. 9

|

issue 1

7-9

EN

The synthesis of ethyl metacrylate in the liquid phase was studied. Tungstophosphoric and molybdophosphoric acids, which belong to heteropolyacids group, were used as a catalyst. The chemical compounds from this group are often utilized in the catalysis with regard to their activity and selectivity. The rate equations, reaction rate constants and equilibrium constants have been determined. The reaction order and the kinetic parameters of the kinetic relations were determined by the integral method. All rate equations are formulated with activities taking the non ideal effects of the compounds into consideration. It was found that the kinetics of the esterification of the presented reactions was non-elementary

2

Niobia supported on silica as a catalyst for Biodiesel production from waste oil

100%

Tesser R., Vitiello R., Carotenuto G., Garcia Sancho C., Vergara A., Maireles Torres P. J., Li C., Di Serio M.

Catalysis for Sustainable Energy

|

2014

|

vol. 1

|

issue 1

EN

The activity and stability of niobia supported on silica catalyst have been tested in continuous micro-pilot reactors, for biodiesel production starting from acid vegetable oils. A catalyst was prepared by the impregnation of silica pellets with a loading of 12% of Nb and was extensively characterized. The activity of this catalyst in both esterification and transesterification was tested in a continuous micro-pilot laboratory plant in which acid oil was fed (FFA 10% w/w) at a temperature of 220°C and at a pressure of 60 bar. The niobia based catalyst resulted in a very active catalyst in both esterification (FFA conversion = 95-90%) and transesterification reactions (FAME yield = 80-90%), and the activity remained quite constant for more than 100 h on stream. Notwithstanding this stability, a non-negligible leaching phenomena has been detected, in the case of long-time continuous runs, as the Nb concentration on the spent catalyst resulted lower than that on the fresh one. The obtained result confirms that the leaching of the active specie is one of the most strong problem in heterogeneous catalysis for biodiesel production.

3

Biosynthesis of ethyl butyrate with immobilized Candida rugosa lipase onto modified Eupergit®C

88%

Spinelli D., Coppi S., Basosi R., Pogni R.

Biocatalysis

|

2014

|

vol. 1

|

issue 1

EN

Lipase from Candida rugosa was immobilized onto the modified Eupergit®C. The support was treated with ethylenediamine and subsequently activated with glutaraldehyde. Enzyme immobilization efficiency was 85%. The optimum pH was close to 6.5 for both the free and immobilized lipase. Immobilized lipase retained its maximum activity in a temperature range of 55 – 60°C. Subsequently, ethyl butyrate synthesis was investigated using immobilized enzyme by esterification of butyric acid with ethanol in solvent-free conditions (23% product yield) and using hexane as a solvent (65% product yield). The acid-alcohol molar ratio and different enzyme amounts were tested as efficient reaction parameters. The biocatalyst maintained 60% of its activity when reused in 8 successive batch reactions in organic solvent. Therefore, the immobilized lipase has demonstrated its potential in practical applications such as short-chain ester synthesis for the food industry.

4

Optimization of rapeseed oil fatty acid esterification with methanol in the presence of sulfuric acid

88%

Brinks J., Malins K., Kampars V., Prilucka J., Apseniece L.

Polish Journal of Chemical Technology

|

2013

|

vol. 15

|

issue 4

54-59

EN

The interest in biodiesel production from low cost feedstocks is still increasing. Such feedstocks usually contain large amounts of free fatty acids, which make the currently employed base catalysts inefficient, thereby promoting the use of acid catalysts. Due to the high activity and low cost, sulfuric acid could become the most widely used acid catalyst for biodiesel production. Research undertaken so far using sulfuric acid for esterifi cation of fatty acids has shown that the products obtained fail to meet the requirements of the standard EN 14214. This paper describes a systematic study of rapeseed oil fatty acids esterification in order to obtain a product complying with the standard EN 14214. The influence of sulfuric acid concentrations (0.1-3.0%), methanol molar ratios (1:1-20:1) and reaction time (0-360 min) was evaluated. Finally, a two-stage esterification process was developed, where in optimal conditions esterification yield of 97.8% and ester content of 99.6% were achieved.

5

Esterification of palmitic acid with epichlorohydrin on anion exchange resin catalyst

88%

Muresan E., Oprea S., Malutan T., Vata M.

Open Chemistry

|

2007

|

vol. 5

|

issue 3

715-726

EN

The esterification reaction of palmitic acid with epichlorohydrin catalyzed by an anionic macroporous resin was studied. Purolite A-500 resin proved to be a very effective catalyst in the synthesis of 3-chloro-2-hydroxypropyl palmitate. The effects of certain parameters such as speed of agitation, catalyst particle size, catalyst loading, temperature, initial molar ratio between reactants on the rate of reaction were studied. It was found that the overall rate is intrinsically kinetically controlled. The structure of synthesized ester was confirmed by FTIR and 1H NMR analyses. [...]

6

A convenient synthesis of long-chain 4-substituted benzyloxycarbonyl alkanethiols for the formation of self assembled monolayers on metal substrates

88%

Angelova P., Kostova K., Hinrichs K., Tsankov D.

Open Chemistry

|

2005

|

vol. 3

|

issue 4

658-667

EN

New 4-substituted benzyl esters of 16-mercaptohexadecanoic acid were prepared by developing a practicable synthetic procedure and using readily available staring materials. The compounds synthesized have been characterized by NMR, MS, IR spectra and elemental analysis. The mercapto derivatives are precursors for the formation of self-assembled monolayers on metal substrates.

7

Pervaporation applied for dewatering of reaction mixture during esterification

75%

Krasiński A., Wierzba P., Grudzień A., Hajmowicz H., Zawada K., Synoradzki L.

Chemical and Process Engineering

|

2016

|

vol. 37

|

issue 1

8

Uncommon applications of statistical methods of the design of experiments in chemical technology and environment protection

75%

Lewandowski G., Ćwirko J.

Polish Journal of Chemical Technology

|

2007

|

vol. 9

|

issue 4

63-67

EN

The review of literature related to the applications of statistic methods of design of experiments in chemical technology and environment protection was presented in the work. The research that consists of two stages: a stage of choosing the best variables describing an experimental object and a stage of proper experimental investigation, seems particularly interesting.An interesting example of an application of statistical strategies in environmental protection is the optimization of photoactivity of TiO2/SiO2 mixture, received by a sol-gel technique. TiO2, due to its specific feature, was applied in the photocatalytic methods of removing toxic compounds from water and air. In the experiments there were used two designs - the fractional factorial design 25-1 (as the elimination one) and the central composite design (as the proper one). Following the data analysis from the elimination plan two variables were eliminated, which helped to simplify the research object.Among other uncommon applications of the design of experiments: the optimization of the conditions for the extraction of natural pigments used in dyeing food, the production of fatty acid methyl esters used as diesel oil substitutes (biodiesel) and the optimization of a supercritical fluid extraction methodology for the analysis of castor oil, should be mentioned.

Refine search results

The influence of the catalyst on the kinetics of ethyl metacrylate synthesis

Niobia supported on silica as a catalyst for Biodiesel production from waste oil

Biosynthesis of ethyl butyrate with immobilized Candida rugosa lipase onto modified Eupergit®C

Optimization of rapeseed oil fatty acid esterification with methanol in the presence of sulfuric acid

Esterification of palmitic acid with epichlorohydrin on anion exchange resin catalyst

A convenient synthesis of long-chain 4-substituted benzyloxycarbonyl alkanethiols for the formation of self assembled monolayers on metal substrates

Pervaporation applied for dewatering of reaction mixture during esterification

Uncommon applications of statistical methods of the design of experiments in chemical technology and environment protection