Wyniki wyszukiwania - Biblioteka Nauki

1

Modele kinetyczne reakcji syntez metakrylanów butylowych

100%

Grzesik M. , Skrzypek J. , Nowak P.

Inżynieria Chemiczna i Procesowa

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1999

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tom T. 20, z. 3

375-386

PL

Badano proces estryfikacji kwasu metakrylowego alkoholami n-butylowym i izobutylowym w izotermicznym reaktorze okresowym bez wyprowadzenia wody. Na podstawie uzyskanych wyników opracowano modele kinetyczne badanych procesów z uwzględnieniem reakcji odwracalnych. Wyznaczono stałe równowagi chemicznej oraz parametry równań kinetycznych.

EN

The esterification process of methacrylic acid with n-butanol and isobutanol have been studied in an experimental isothermal batch reactor. Basing on experimental results, the rigorous kinetic models were derived, including the reversible reactions. The equilibrium constants and kinetic parameters have been determined.

2

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

80%

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

Catalysis for Sustainable Energy

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2014

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tom 1

|

nr 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

Badania procesu estryfikacji kwasu benzoesowego glikolem dietylenowym

80%

Krogulecki A. , Kałędkowski B. , Szemień M.

Przemysł Chemiczny

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2007

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tom T. 86, nr 10

974-977

4

Consider reactive separations

80%

Kołodziej A. , Jaroszyński M. , Janus B. , Kleszcz T.

Ars Separatoria Acta

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2009/2010

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tom No. 7

11-20

EN

Reactive separation (RS) is the combination of a chemical (catalytic) reaction and a separation technique. For reactive distillation (RD), the reaction is combined with distillation. Rapid development of RS is the result of growing environmental demands and increasing energy costs. Several processes are performed using RD, such as esterification, etherification (fuel antiknocks), and hydrodesulphurisation. Other RS techniques also develop rapidly. However, the success has not come without some serious problems. The heterogeneous proton catalysts still do not meet the requirements of many processes. The column internals with a built-in catalyst are rather sparse and expensive and their characteristics are not studied well enough. Therefore intensive studies are still being performed. This study presents a brief summary of the processes realisable with the usage of reactive distillation, catalysts, and column internals. Some interesting research results and application examples are also quoted.

5

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

80%

Grzesik M. , Witczak T.

Polish Journal of Chemical Technology

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2007

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tom 9

|

nr 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

6

Biodiesel Production of Palm Oil Mill Effluent by Using Hydrotalcite Catalyst

80%

Agustina T. E. , Heraldy E. , Hadiah F. , Hasanudin , Arita S. , Prakoso T. , Sari T. I. , Suprapto B. Y. , Putra M. F. K. , Ramadhani D. L.

Journal of Ecological Engineering

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2022

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tom Vol. 23, nr 6

172--181

EN

Biodiesel is currently preferred for consumption and has been widely used as a substitute for diesel. This study aimed to determine the effect of various methanol-to-oil ratios in the esterification process and also the effect of hydrotalcite catalyst weight on the transesterification product. The catalyst was characterized with SEM, XRD, FTIR, and TG-DTG-DTA. The esterification process was operated at various oil-to-methanol ratios, i.e., 1:12–1:36 and the transesterification was performed using several catalyst weights, 0.5%–2.5%. The results showed that the optimum conditions of esterification were at the 1:30 molar ratio of oil-to-methanol, which decreased the amount of acid number by 95.75%, while the optimum condition of transesterification was at 1.5% catalyst weight. The characteristics of biodiesel using 0.5–2% hydrotalcite catalyst (acid number, total glycerol, free glycerol, ester levels, viscosity, density, oxidation stability) have met the Indonesian biodiesel standard of SNI-04-7182-2012.

7

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

70%

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

Polish Journal of Chemical Technology

|

2013

|

tom 15

|

nr 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.

8

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

70%

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

Polish Journal of Chemical Technology

|

2013

|

tom Vol. 15, nr 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.

9

Esterification of palmitic acid with epichlorohydrin on anion exchange resin catalyst

70%

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

Open Chemistry

|

2007

|

tom 5

|

nr 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. [...]

10

Fast and easy preparation of a novel highly acidic sulfonic-functionalized SBA-1 cubic mesoporous catalyst and its application in the esterification of palmitic acid

70%

Abbasi A. , Mahjoub A. R. , Badiei A. R.

Materials Science Poland

|

2010

|

tom Vol. 28, No. 3

617--624

EN

Propylsulfonic acid-functionalized cubic mesoporous silica was prepared through in situ oxidization of mercaptopropyl groups with H2O2 during co-condensation of tetraethyl orthosilicate and 3-mercaptopropyl trimethoxysilane under strong acidic conditions. The materials obtained with 5-20 mol % loadings of sulfonic acid groups had surface areas of up to 1300 m2/g and pore sizes of around 2.5 nm. Next, the catalytic activity of this material was investigated in esterification of palmitic acid as a compound model in the process of biodiesel production. Methyl ester production by this new nanoporous catalyst shows a very remarkable yield during a mild liquid phase reaction.

11

Carbon-based acid catalyst from waste seed shells: preparation and characterization

70%

Wang L. H. , Liu H. , Li L.

Polish Journal of Chemical Technology

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2015

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tom Vol. 17, nr 4

37--41

EN

A carbon-based solid acid catalyst was prepared by the sulfonation of carbonized seed shells of Jatropha curcas (J. curcas L.). The structure of amorphous carbon consisting of polycyclic aromatic carbon sheets attached a high density of acidic SO3H groups (2.0 mmol · g−1) was identified with scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The performance of the solid acid catalyst was evaluated for biodiesel production in the esterification of oleic acid with methanol. 95.7% yield of biodiesel was obtained after 2 h reaction and the conversions with reused catalyst varied in the range of 95.7% to 95.1%, showing better activity and stability than commercial catalyst amberlyst-46. It was also observed that the prepared catalyst showed enhanced activity in the transesterification of triolein with methanol when compared with other solid acid catalysts. A synergistic effect results from the high density of SO3H groups and the good access of reactants to the acidic sites can be used to explain the excellent catalytic activity, as well as the strong affinity between the hydrophilic reactants and the neutral OH groups bonded to the polycyclic aromatic carbon rings.

12

A novel highly acidic sulfonic functionalized SBA-1 cubic mesoporous catalyst and its application in the esterification of palmitic acid

70%

Abbasi A. , Reza Mahjoub A. , Badiei A. R.

Materials Science Poland

|

2010

|

tom Vol. 28, No. 2

565--572

EN

Propylsulfonic acid functionalized cubic mesoporous silica was fabricated through in situ oxidization of mercaptopropyl groups with H2O2 during co-condensation of tetraethyl orthosilicate and 3-mercaptopropyl trimethoxysilane under strong acidic conditions. The materials obtained with 5-20 mol % loadings of sulfonic acid groups had surface areas of up to 1300 m2/g and pore sizes of ca. 2.5 nm. The catalytic activity of this material was investigated: tests were performed on the esterification of palmitic acid being a model compound in the process of biodiesel production. Methyl ester yield on this new nanoporous catalyst is very remarkable during a mild liquid phase reaction.

13

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

70%

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

Open Chemistry

|

2005

|

tom 3

|

nr 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.

14

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

70%

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

Biocatalysis

|

2014

|

tom 1

|

nr 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.

15

Novel and facile synthesis of transparent-monolithic TiO2 gels by sol-gel method based on an esterification reaction

70%

Elghniji K. , Rabah Z. A. , Elaloui E.

Materials Science Poland

|

2016

|

tom Vol. 34, No. 3

633--640

EN

Transparent TiO2 monoliths were obtained through a modified sol-gel route from titanium isopropoxide as a precursor. By controlling the hydrolysis of this precursor through the intermediate of esterification reaction between acetic acid and isopropanol at 40 °C, transparent TiO2 xerogel monoliths were obtained. The monoliths prepared by this method were transparent in the wavelengths between 400 nm and 700 nm. Fourier transform infrared (FT-IR) spectroscopy suggested that the acetic acid played also an active role as a chelating agent, forming Ti[(OH)y(OOCCH3)x] less reactive species. Powder X-ray diffraction confirmed the amorphous-to-anatase phase transformation with the formation of unknown Ti-containing complex at 90 °C. Only anatase TiO2 could be observed in the samples calcined at 250 °C and 450 °C. Optical aspects of the gel (transparent-transluscent transformation of monolithic gel) and gelation time were controlled by changing the amount of external water.

16

Oczyszczanie ścieków technologicznych z kwasu octowego metodą destylacji reaktywnej - modelowanie kinetyki reakcji estryfikacji

60%

Hehlmann J. , Sobecki M. , Gądek M.

Rocznik Ochrona Środowiska

|

2011

|

tom Tom 13

859-874

PL

Zainteresowanie ochroną środowiska leży u podstaw zrównoważonej gospodarki światowej. Koncepcja wytrzymałości światowego systemu ekologicznego opiera się na dwóch podstawowych pojęciach: potrzeby i ograniczenia. W myśl tej tezy prowadzone są poszukiwania nowych "ekologicznych" technologii oraz metod modernizacji już istniejących. Destylacja reaktywna jest jednym z tych innowacyjnych trendów. Pomimo faktu, że w przemyśle chemicznym idea tworzenia procesów hybrydowych nie stanowi novum, to jednak dopiero na przestrzeni ostatnich lat, wskutek wzrostu popytu na dodatki do benzyn bezołowiowych, proces destylacji reaktywnej zaczął cieszyć się zainteresowaniem. W roku 1984 koncern Eastman Kodak Chemicals wykorzystując destylację reaktywną rozpoczął produkcję MTBE na skalę przemysłową. Kombinację dziewięciu kolumn destylacyjnych i reaktora zastąpiono jedną kolumną reaktywną [1, 2].

EN

The paper presents possibilities of reactive distillation column application in recovery of acetic acid from waste water and industrial streams. Reaction zone of RD column is equipped with hybrid structural plate. This is new apparatus solution for reactive separation process. There was investigated kinetics of esterification in diluted water solution. Experimental conversion was compared with modeling in process simulator using pseudo homogenous and heterogenous kinetics equation. Hybrid structural plate (Fig. 1b) is a solution that allows to perform the esterification reaction of acetic acid using methanol. The study aimed at mapping the process conditions used in the plate column used in RD column. Satisfying (ca. 50%) conversion rate of 99.5% acetic acid was obtained. The reaction in aqueous solution runs slower, due to the diluted streams of reagents, shift of the equilibrium of reaction and limited use of catalyst accumulated in the perforated container. Presented construction solution, with some modifications, is the subject of the patent application being developed [15]. Esterification of concentrated solutions of acetic acid in plate devices can be described with a heterogeneous model, and diluted with pseudohomogenic model. Mass transport, assuming ideal mixing in the heterogeneous system is very complicated and seems to have a slightly different mechanism for three-phase system (vapour/liquid/solid) in the reactive column with plates working on the idea barbotage than catalytic structural fills. Application of kinetic equations from pseudohomogenic or heterogeneous models is correct for the RD column equipped with only the dumped or structural fill of KATAPAK type [14], working under the streamlined regime.

17

Wykorzystanie frakcji izobutenowej w procesach eteryfikacji i estryfikacji związków pochodzących ze źródeł odnawialnych

60%

Kijeński J. , Jamróz M. E. , Tęcza W. , Migdał A. , Jarosz M. , Walisiewicz-Niedbalska W. , Zielecka M.

Przemysł Chemiczny

|

2006

|

tom T. 85, nr 8-9

594-597

PL

W reakcji eteryfikacji gliceryny izobutenem zastosowano grupę stałych katalizatorów kwasowych opartych na Nafionie. Stosowano różne techniki tworzenia kompozytów Nafionu w celu zwiększenia jego powierzchni katalitycznej. Osiągnięto zwiększenie selektywności procesu eteryfikacji i znaczne ograniczenie ubocznych reakcji tworzenia dimerów izobutenu. Te same układy katalityczne zastosowano w procesie estryfikacji kwasów tłuszczowych izobutenem uzyskując względnie wysoką wydajność estrów.

EN

Nafion H(10 and 20%)-on-SiO2 (Aerosil 200) prepd. by impregnation in resp. H2O and MeOH, and for comparison, Amber- lyst 35 dry, Nafion NR50 and SAC-13, BET surface 65, 125, 45, 0.02, and 200 m2/g, resp., were examd. as catalysts in etherification of glycerol (90°C, 17 atm, 6 hrs, glycerol/iso- butene 1:5 by moles, catalyst 5%) and esterification of oleic acid (90oC, 6 hrs, acid/isobutene 1:2 by moles, catalyst 7% reactants wt. basis) run with a com. (11.4:28.4:60 w/w) isobutane-1-butene-isobutene fraction. The 10% and the 20% composites had comparable acid strengths (0.18 and 0.21 meq H+/g, resp.), were more active than the ref. catalysts, converted glycerol in 90.5 and 81.2%, resp. (98% selectivity toward tert-Bu ethers) and oleic acid in 50+% each, and gave only 2.4 and 7.8% isobutene dimers in the etherificate.

18

Badania kinetyczne procesu estryfikacji bezwodnika maleinowego n– i sec-butanolem w obecności wybranych katalizatorów

60%

Organek M. , Kulawska M. , Organek W. , Koreń-Szwarc B.

Przemysł Chemiczny

|

2016

|

tom T. 95, nr 7

1385--1387

PL

Przeprowadzono syntezę maleinianu n- i sec--butylowego w doświadczalnym izotermicznym reaktorze półprzepływowym. Jako katalizator zastosowano kwas siarkowy, kwas wolframofosforowy oraz Nafion SAC-13. Stwierdzono, że szybkość wszystkich katalitycznych reakcji estryfikacji bezwodnika maleinowego butanolami odpowiada kinetyce reakcji drugorzędowej.

EN

Bu and EtCHMe maleates were synthesized by esterification of maleic acid with resp. alcs. in presence of H2SO4, H3[P(W3O10)4]·6H2O or Nafion resin at 383–413 K to det. the reaction kinetics. The reactions had 2nd order kinetics in respect to acid and alc.

19

Pervaporation applied for dewatering of reaction mixture during esterification

60%

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

|

nr 1

20

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

60%

Lewandowski G. , Ćwirko J.

Polish Journal of Chemical Technology

|

2007

|

tom 9

|

nr 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.