Log in

Relevant bibliographies by topics / Phase-transfer catalyst / Journal articles

To see the other types of publications on this topic, follow the link: Phase-transfer catalyst.

Journal articles on the topic 'Phase-transfer catalyst'

Author: Grafiati

Published: 4 June 2021

Last updated: 18 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Phase-transfer catalyst.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Jurczak, Janusz, Maciej Majdecki, Patryk Niedbała, and Agata Tyszka-Gumkowska. "Assisted by Hydrogen-Bond Donors: Cinchona Quaternary Salts as Privileged Chiral Catalysts for Phase-Transfer Reactions." Synthesis 53, no. 16 (April 1, 2021): 2777–86. http://dx.doi.org/10.1055/a-1472-7999.

Full text

Abstract:

AbstractThis short review is devoted to asymmetric phase-transfer reactions that employ hybrid ammonium Cinchona catalysts supported by possessing hydrogen-bond donor groups. We present recent advances utilizing this type of catalyst in the field of biphasic reaction systems. The main emphasis is placed on the advantages of additional functional groups present in the structure of the catalyst, such as hydroxy, amide, (thio)urea or squaramide.1 Introduction2 Phase-Transfer Hybrid Cinchona Catalysts with a Free Hydroxy Group3 (Thio)urea Hybrid Cinchona Catalysts4 Hybrid Amide-Based Catalysts Bearing a Cinchona Scaffold5 Conclusions

APA, Harvard, Vancouver, ISO, and other styles

2

Kondo, Masaru, Kento Nakamura, Chandu G. Krishnan, Shinobu Takizawa, Tsukasa Abe, and Hiroaki Sasai. "Photoswitchable Chiral Phase Transfer Catalyst." ACS Catalysis 11, no. 3 (January 26, 2021): 1863–67. http://dx.doi.org/10.1021/acscatal.1c00057.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Xiao, Cong Li, Tao Fan, and Zhi Qi Gao. "The Benzoin Condensation Reaction under Different Ultrasonic Frequency and Phase Transfer Catalyst." Applied Mechanics and Materials 457-458 (October 2013): 313–17. http://dx.doi.org/10.4028/www.scientific.net/amm.457-458.313.

Full text

Abstract:

This paper summarizes the method of benzoin condensation reaction, and studied the influence of benzoin yield under different ultrasonic frequency and phase transfer catalyst, Experiments prove that benzyltriethylammonium bromide is the best phase transfer catalyst in three catalysts and the benzoin yield increased with the increase of ultrasonic frequency.

APA, Harvard, Vancouver, ISO, and other styles

4

Bashpa, P., P. Rajendran, and K. Bijudas. "Oxidation of Cyclohexanol and Cyclohexanone by Monochromate Ions in Organic Solvents and on Solvent Free Microwave Irradiation under Phase Transfer Catalysis - A Comparative Study." Asian Journal of Chemistry 33, no. 9 (2021): 2033–37. http://dx.doi.org/10.14233/ajchem.2021.23285.

Full text

Abstract:

Oxidation of cyclohexanol and cyclohexanone were carried out by acidified monochromate ions in ethyl acetate and toluene under phase transfer catalysis and also in solvent free condition under microwave irradiation. The extraction of monochromate ions from aqueous medium to organic phase was carried by employing various phase transfer catalysts in the presence of mineral acids. The effect of [catalyst] and [mineral acid] on extraction of monochromate from aqueous phase to organic phase was also studied. The product obtained, namely adipic acid obtained with both reactants was characterized by its melting point and infrared spectral technique. The reaction was over within 15 min with more than 85% yield at a temperature of 323 K under microwave irradiation where as it gave around 70% yield at 353 K within 150 min under phase transfer catalysis condition. The enhanced reaction rate and high yield of product substantiate the application of phase transfer catalytic technique under microwave irradiation for organic synthesis. A suitable mechanism for the oxidation of substrates by monochromate under phase transfer catalysis is also suggested.

APA, Harvard, Vancouver, ISO, and other styles

5

Iizawa, Takashi. "Phase transfer catalyzed polymerization: Syntheses of polymers using phase transfer catalyst." Kobunshi 38, no. 11 (1989): 1014–17. http://dx.doi.org/10.1295/kobunshi.38.1014.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Bijudas, K., and P. Bashpa. "Oxidation of Benzaldehyde and Substituted Benzaldehydes by Permanganate under Phase Transfer Catalysis in Non Polar Solvents." IRA-International Journal of Applied Sciences (ISSN 2455-4499) 5, no. 3 (December 17, 2016): 110. http://dx.doi.org/10.21013/jas.v5.n3.p1.

Full text

Abstract:

<div><p class="Affiliation"><em>Phase transfer catalysed oxidation of benzaldehyde and substituted benzaldehydes by permanganate ion have been studied in non polar solvents like ethyl acetate and toluene. The obtained products were charecterised by melting point determination and infra red spectral analysis. Benzoic acid and corresponding substituted benzoic acids were formed as the product with very high yield. The oxidation reactions were carried out by using various quaternary ammonium and phosphonium salts as phase transfer catalyst. The effect of non polar solvents and various phase transfer catalysts on yield of product was also carried out.</em></p></div>

APA, Harvard, Vancouver, ISO, and other styles

7

Sankarshana, T., J. Soujanya, and A. Anil Kumar. "Triphase Catalysis Using Silica Gel as Support." International Journal of Chemical Reactor Engineering 11, no. 1 (July 4, 2013): 347–52. http://dx.doi.org/10.1515/ijcre-2013-0007.

Full text

Abstract:

Abstract The oxidation reaction of 2-ethyl-1-hexanol with potassium permanganate in the presence and absence of silica-gel-supported phase-transfer catalyst (PTC) in triphasic conditions was studied. In a batch reactor, the performance of the solid-supported catalysts was compared with unsupported catalyst and without the catalyst. The effect of speed of agitation, catalyst concentration, potassium permanganate concentration and temperature on reaction rate was studied. The reaction is found to be in the kinetic regime. The rate of reaction with the catalyst immobilised on the silica gel was less compared to the catalyst without immobilisation. Triphase catalysis with supported PTCs has potential applications in the continuous quest for greener industrial practices.

APA, Harvard, Vancouver, ISO, and other styles

8

Simagina, Valentina I., Elena S. Tayban, Ekaterina D. Grayfer, Anna G. Gentsler, Oksana V. Komova, and Olga V. Netskina. "Liquid-phase hydrodechlorination of chlorobenzene by molecular hydrogen: The influence of reaction medium on process efficiency." Pure and Applied Chemistry 81, no. 11 (October 26, 2009): 2107–14. http://dx.doi.org/10.1351/pac-con-08-10-12.

Full text

Abstract:

Catalytic hydrodechlorination (HDCl) of chlorobenzene was carried out in a two-phase aqueous–organic solvent system and a single-phase solvent composed of saturated KOH solution in a secondary alcohol over Pd-based catalysts at 50 °C and atmospheric pressure of H2. It was shown that an aqueous–organic solvent system containing propan-2-ol and aqueous KOH increases catalyst activity by promoting mass transfer of the formed chloride ions to water phase that prevents catalyst deactivation. It is inferred that propan-2-ol favors hydrogen activation during the HDCl process. Use of the Pd catalysts based on hydrophobic carbon support enables chlorobenzene HDCl to proceed in a two-phase solvent at a satisfactory rate, even in the absence of phase-transfer catalysts.

APA, Harvard, Vancouver, ISO, and other styles

9

BOGDAL, Dariusz, and JAN PIELICHOWSKI. "Polymers as phase transfer catalysts. Part I. Catalyst structure and factors governing catalyst activity." Polimery 42, no. 11/12 (November 1997): 651–55. http://dx.doi.org/10.14314/polimery.1997.651.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Schoeneberger, Elsa M., and Gerrit A. Luinstra. "Investigations on the Ethylene Polymerization with Bisarylimine Pyridine Iron (BIP) Catalysts." Catalysts 11, no. 3 (March 23, 2021): 407. http://dx.doi.org/10.3390/catal11030407.

Full text

Abstract:

The kinetics and terminations of ethylene polymerization, mediated by five bisarylimine pyridine (BIP) iron dichloride precatalysts, and activated by large amounts of methyl aluminoxane (MAO) was studied. Narrow distributed paraffins from initially formed aluminum polymeryls and broader distributed 1-polyolefins and (bimodal) mixtures, thereof, were obtained after acidic workup. The main pathway of olefin formation is beta-hydrogen transfer to ethylene. The rate of polymerization in the initial phase is inversely proportional to the co-catalyst concentration for all pre-catalysts; a first-order dependence was found on ethylene and catalyst concentrations. The inhibition by aluminum alkyls is released to some extent in a second phase, which arises after the original methyl groups are transformed into n-alkyl entities and the aluminum polymeryls partly precipitate in the toluene medium. The catalysis is interpretable in a mechanism, wherein, the relative rate of chain shuttling, beta-hydrogen transfer and insertion of ethylene are determining the outcome. Beta-hydrogen transfer enables catalyst mobility, which leads to a (degenerate) chain growth of already precipitated aluminum alkyls. Stronger Lewis acidic centers of the single site catalysts, and those with smaller ligands, are more prone to yield 1-olefins and to undergo a faster reversible alkyl exchange between aluminum and iron.

APA, Harvard, Vancouver, ISO, and other styles

11

Wang, Jian, Guangping Wu, Wenhui Xuan, Lishan Peng, Yong Feng, Wei Ding, Li Li, Qiang Liao, and Zidong Wei. "A framework ensemble facilitates high Pt utilization in a low Pt loading fuel cell." Catalysis Science & Technology 11, no. 8 (2021): 2957–63. http://dx.doi.org/10.1039/d1cy00028d.

Full text

Abstract:

Rationally designing the structure of catalyst layer in MEA to achieve the dispersion of active sites at the cross of three-phase field and the effective transfer network paths for protons through catalysts and catalyst layer.

APA, Harvard, Vancouver, ISO, and other styles

12

Depreux, P., and A. Marcincal-Lefebvre. "Application des conditions de réaction par transfert de phase à la synthèse d'amino-éthers dérivés du trans phénoxy-2 cyclohexanol." Canadian Journal of Chemistry 64, no. 3 (March 1, 1986): 626–32. http://dx.doi.org/10.1139/v86-101.

Full text

Abstract:

Amino-ethers of trans-2-phenoxycyclohexanol were prepared by methods involving anhydrous conditions (sodium alkoxides in xylene) or phase transfer catalysis conditions (liquid–liquid or solid–liquid two-phase systems). Various factors were optimized. In the liquid–liquid two-phase system, when no catalyst was added, reaction proceeds with comparable or even better yields than with some PTC catalysts, a quaternary salt being formed insitu. It was shown that the deprotonation of ROH takes place at the interface, since there was no OH− extraction in organic medium and the yield depends on the stirring speed. In the presence of Aliquat, the yield does not change with the organic concentration of the catalyst. Statistical correlations obtained between the variations in yield and several other parameters were good.

APA, Harvard, Vancouver, ISO, and other styles

13

Sathiyaraj, Manickam, and Perumal Venkatesh. "Synthesis of 1-butoxy-4-tert-butylbenzene under The Effect of Multi-site Phase Transfer Catalysis System – A Kinetic Study." Bulletin of Chemical Reaction Engineering & Catalysis 15, no. 2 (April 26, 2020): 405–14. http://dx.doi.org/10.9767/bcrec.15.2.7519.405-414.

Full text

Abstract:

Phase transfer catalysis technique proved to be a useful method for synthesizing various organic compounds under heterogeneous reactions and recognized as a viable environmentally friendly. The influence of a new multi site phase transfer catalyst (MPTC) is the synthesis of 1-butoxy-4-tertbutylbenzene from 4-tert-butylphenol with 1-bromobutane (BB) under heterogeneous solid-liquid condition using potassium hydroxide as a base at 60 °C. The higher conversion of 1-bromobutane was achieved by using the synergistic condition of multi-site phase transfer catalyst in better efficacy. The reaction rate enhanced by decreases the volume of water. The apparent the reaction rate was found to be pseudo-first order kinetics. The apparent rate constant was increased linearly with the increase in the concentration of various parameters, such as: MPTC, temperature, potassium hydroxide, and stirring speed. The activation energy (Ea) was also calculated through the Arrhenius plot. Copyright © 2020 BCREC Group. All rights reserved

APA, Harvard, Vancouver, ISO, and other styles

14

Roy, René, François D. Tropper, and Chantal Grand-Maître. "Syntheses of glycosyl phosphates by phase transfer catalysis." Canadian Journal of Chemistry 69, no. 9 (September 1, 1991): 1462–67. http://dx.doi.org/10.1139/v91-216.

Full text

Abstract:

The peracetylated glycosyl bromides of D-glucose (1), D-galactose (2), and D-lactose (5) were treated with dibenzyl phosphate in a catalytic two-phase system using tetrabutylammonium hydrogen sulfate as catalyst. The reactions proceeded by complete inversion at the anomeric centers and afforded a new stereospecific entry into 1,2-trans-β-D-glycosyl phosphates of peracetylated D-glucose (3), D-galactose (4), and the disaccharide D-lactose (6) in 83, 73, and 83% yields respectively. Interestingly, the glycosyl chloride 7 furnished the oxazoline 9 rather than the expected glycosyl phosphate 8. Key words: phase transfer catalysis, glycosyl phosphates, phosphotriesters.

APA, Harvard, Vancouver, ISO, and other styles

15

Ni, Xiong-Wei. "Another Critical Look at Three-Phase Catalysis." Pharmaceutical Fronts 02, no. 03 (September 2020): e117-e127. http://dx.doi.org/10.1055/s-0040-1722219.

Full text

Abstract:

AbstractThree-phase catalysis, for example, hydrogenation, is a special branch of chemical reactions involving a hydrogen reactant (gas) and a solvent (liquid) in the presence of a metal porous catalyst (solid) to produce a liquid product. Currently, many reactors are being used for three-phase catalysis from packed bed to slurry vessel; the uniqueness for this type of reaction in countless processes is the requirement of transferring gas into liquid, as yet there is not a unified system of quantifying and comparing reactor performances. This article reviews current methodologies in carrying out such heterogeneous catalysis in different reactors and focuses on how to enhance reactor performance from gas transfer perspectives. This article also suggests that the mass transfer rate over energy dissipation may represent a fairer method for comparison of reactor performance accounting for different types/designs of reactors and catalyst structures as well as operating conditions.

APA, Harvard, Vancouver, ISO, and other styles

16

Narayanan, V. Lakshmi, and M. J. Umapathy. "Studies on the Depolymerization of Poly(ethylene terephthalate) Using 1, 1, 2, 2-Tetramethyl-1-Benzyl-2-n-Octyl Ethylene-1, 2-Diammonium Bromide Chloride as Phase Transfer Catalyst." Advanced Materials Research 938 (June 2014): 164–69. http://dx.doi.org/10.4028/www.scientific.net/amr.938.164.

Full text

Abstract:

1,4-Bis (dimethyl) benzyl octyl ethylene diammonium bromide chloride has been synthesized, characterized and applied as new phase transfer catalyst in the alkaline hydrolysis of PET leading to depolymerisation. The new phase transfer catalyst has been compared with the alkaline hydrolysis of PET using zinc sulfate as catalyst in the depolymerization. It was found that the newly synthesized phase transfer catalyst exhibited excellent conversion than the alkaline hydrolysis of PET using zinc sulfate as catalyst.

APA, Harvard, Vancouver, ISO, and other styles

17

Sharma, Lalit, Subhash Chander Sharma, and Saroj. "Studies in Asymmetric Epoxidation of Chalcone Using Quaternary Salts and Nonionic Surfactants Based on 6-Amino-6-deoxy-glucose as Chiral Phase Transfer Catalysts." E-Journal of Chemistry 8, no. 3 (2011): 1293–97. http://dx.doi.org/10.1155/2011/873253.

Full text

Abstract:

Quaternary salts and nonionic surfactants based on 6-amino-6-deoxy-glucose were explored as chiral phase transfer catalysts for the asymmetric epoxidation of chalcone. Quaternary salts used in the present study, were void of any branched chain or long hydrocarbon chain, whereas the sugar based nonionic surfactants have a long hexadecyl moiety as tail. It was observed that quaternary salts showed no activity as phase transfer catalysts but sugar based nonionic surfactants acted as chiral phase transfer catalysts. It was also revealed that hydrophilicity of the surfactant favors more yield whereas stereochemistry governs enantioselectivity. (6,6'-Hexadecylimino) bis(6-deoxy-1,2-O-isopropylidene-α-D-glucofuranose) was found to be the most suitable chiral phase transfer catalyst, resulting asymmetric epoxidation of chalcone with 90% yield and 16.5% enantiomeric excess (ee).

APA, Harvard, Vancouver, ISO, and other styles

18

Ido, Tadaatsu, Ken Yamaguchi, Hajime Itoh, and Shigeo Goto. "Catalytic Activity of Phase Transfer Catalyst in a Third Phase." KAGAKU KOGAKU RONBUNSHU 21, no. 4 (1995): 715–22. http://dx.doi.org/10.1252/kakoronbunshu.21.715.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Ido, Tadaatsu, Ken Yamaguchi, Takanobu Yamamoto, and Shigeo Goto. "Effective Use of Phase Transfer Catalyst in a Third Phase." KAGAKU KOGAKU RONBUNSHU 21, no. 4 (1995): 804–8. http://dx.doi.org/10.1252/kakoronbunshu.21.804.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Lewandowski, Grzegorz. "Efficiency of selected phase transfer catalysts for the synthesis of 1,2-epoxy-5,9-cyclododecadiene in the presence of H2O2/H3PW12O40 as catalytic system." Polish Journal of Chemical Technology 15, no. 3 (September 1, 2013): 96–99. http://dx.doi.org/10.2478/pjct-2013-0053.

Full text

Abstract:

Abstract The results of the studies on the influence of the phase transfer catalyst on the epoxidation of (Z,E,E)-1,5,9-cyclododecatriene (CDT) to 1,2-epoxy-5,9-cyclododecadiene (ECDD) in the H2O2/H3PW12O40 system by a method of phase transfer catalysis (PTC) were presented. The following quaternary ammonium salts were used as phase transfer catalysts: methyltributylammonium chloride, (cetyl)pyridinium bromide, methyltrioctylammonium chloride, (cetyl)pyridinium chloride, dimethyl[dioctadecyl(76%)+dihexadecyl(24%)] ammonium chloride, tetrabutylammonium hydrogensulfate, didodecyldimethylammonium bromide and methyltrioctylammonium bromide. Their catalytic activity was evaluated on the basis of the degree of CDT and hydrogen peroxide conversion and the selectivities of transformation to ECDD in relation to consumed CDT and hydrogen peroxide. The most effective PT catalysts were selected based on the obtained results. Among the onium salts under study, the epoxidation of CDT with hydrogen peroxide proceeds the most effectively in the presence of methyltrioctylammonium chloride (Aliquat® 336) and (cetyl)pyridinium chloride (CPC). The relatively good results of CDT epoxidation were also achieved in the presence of Arquad® 2HT and (cetyl)pyridinium bromide

APA, Harvard, Vancouver, ISO, and other styles

21

Zahalka, Hayder A., and Yoel Sasson. "Esterification of 1,4-dichlorobutane with sodium formate under solid–liquid phase transfer catalysis. A kinetic study." Canadian Journal of Chemistry 67, no. 2 (February 1, 1989): 245–49. http://dx.doi.org/10.1139/v89-040.

Full text

Abstract:

Kinetic data are reported regarding the esterification of 1,4-dichlorobutane with sodium formate catalyzed by quaternary ammonium salts as a model for reactions in series, under solid–liquid phase transfer conditions. The process was found to follow a consecutive first-order mechanism of the general type A → R → S. The reactivity of the quaternary ammonium salts with regard to the counteranion was Cl− > Br− > 1− > HSO4−. The reaction rate was linearly dependent on catalyst concentration up to 12 mol% of catalyst relative to the substrate. Above this concentration the rate was constant and independent of the amount of the catalyst. The activation energy of the two consecutive steps was found to be similar (21 kcal/mol). Therefore, the product distribution (R/S) is not appreciably affected by temperature. A mechanism termed "Thin aqueous boundary layer" is suggested for nucleophilic displacement reactions under solid–liquid phase transfer conditions. Keywords: phase transfer catalysis, series reactions, kinetic study.

APA, Harvard, Vancouver, ISO, and other styles

22

Egami, Hiromichi, Tomoki Niwa, Hitomi Sato, Ryo Hotta, Daiki Rouno, Yuji Kawato, and Yoshitaka Hamashima. "Dianionic Phase-Transfer Catalyst for Asymmetric Fluoro-cyclization." Journal of the American Chemical Society 140, no. 8 (February 12, 2018): 2785–88. http://dx.doi.org/10.1021/jacs.7b13690.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Gouverneur, V., G. Pupo, F. Ibba, D. Ascough, A. Vicini, P. Ricci, K. Christensen, et al. "Hydrogen-Bonding Phase-Transfer Catalyst Enabled Asymmetric Fluorination." Synfacts 14, no. 10 (September 17, 2018): 1108. http://dx.doi.org/10.1055/s-0037-1611011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Chou, Su-Chu, and Hung-Shan Weng. "Characterization of the polymer-supported phase transfer catalyst." Journal of Applied Polymer Science 39, no. 8 (April 20, 1990): 1665–79. http://dx.doi.org/10.1002/app.1990.070390805.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Kim, Youngmin, Surajit Some, and Hyoyoung Lee. "Graphene oxide as a recyclable phase transfer catalyst." Chemical Communications 49, no. 50 (2013): 5702. http://dx.doi.org/10.1039/c3cc42787k.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Daneshfar, Ali, Farbod Ansari, and Siavash Hasanvandi. "Spectrophotometric Determination of Colchicine by Phase Transfer Catalyst." Oriental Journal Of Chemistry 28, no. 1 (March 18, 2012): 89–96. http://dx.doi.org/10.13005/ojc/280113.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Dehmlow, E. V. "Influence of phase transfer catalyst structure on selectivity." Russian Chemical Bulletin 44, no. 11 (November 1995): 1998–2005. http://dx.doi.org/10.1007/bf00696697.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Wang, Hui, Hongfei Lin, Xiaohu Li, Rui Ren, Jianglong Pu, Haiping Zhang, Ying Zheng, Jianshe Zhao, Siauw Ng, and Hui Zhang. "Application of Phase Transfer Catalysis in the Esterification of Organic Acids: The Primary Products from Ring Hydrocarbon Oxidation Processes." Catalysts 9, no. 10 (October 13, 2019): 851. http://dx.doi.org/10.3390/catal9100851.

Full text

Abstract:

For enhancing the cetane number (CN) of diesel fraction, the selective oxidative ring opening method was applied to upgrade ring hydrocarbons. Organic acids, one of the main products from this oxidative reaction, being esterified by the phase transfer catalysis (PTC) approach were studied. Adipic acid, benzoic acid, and phthalic acid were used as model compounds. Reaction time, reaction temperature, the amount of water, and the amount of catalyst in the esterification process were investigated and optimized using orthogonal experimental design method. The kinetics of esterification process was then conducted under the optimal condition. The types of catalysts and organic acids, the amount of catalyst and water were also investigated. The PTC esterification was one rate controlling reaction on the interface between the aqueous phase and the oil phase. Hydrophobicity is a key factor for converting benzoic acid, adipic acid, and phthalic acid to the corresponding esters. It was found that around 5–8% water is the optimal quantity for the given reaction system. Two cases of esterification processes of PTC were proposed.

APA, Harvard, Vancouver, ISO, and other styles

29

Dekamin, Mohammad G., Shadpour Mallakpour, and Maryam Ghassemi. "Sulfate catalysed multicomponent cyclisation reaction of aryl isocyanates under green conditions." Journal of Chemical Research 2005, no. 3 (March 2005): 177–79. http://dx.doi.org/10.3184/0308234054213582.

Full text

Abstract:

Sulfate anion, as a novel anionic catalyst, promotes the multicomponent cyclisation of aryl isocyantes to give heterocyclic symmetrical isocyanurates selectively under solvent-free conditions. The use of phase transfer catalysts reduces reaction times by 4-16 times.

APA, Harvard, Vancouver, ISO, and other styles

30

Kopeć, Daniel, Stefan Baj, and Agnieszka Siewniak. "Ultrasound-Assisted Green Synthesis of Dialkyl Peroxides under Phase-Transfer Catalysis Conditions." Molecules 25, no. 1 (December 28, 2019): 118. http://dx.doi.org/10.3390/molecules25010118.

Full text

Abstract:

The dialkyl peroxides, which contain a thermally unstable oxygen–oxygen bond, are an important source of radical initiators and cross-linking agents. New efficient and green methods for their synthesis are still being sought. Herein, ultrasound-assisted synthesis of dialkyl peroxides from alkyl hydroperoxides and alkyl bromides in the presence of an aqueous solution of an inorganic base was systematically studied under phase-transfer catalysis (PTC) conditions. The process run in a tri-liquid system in which polyethylene glycol as a phase-transfer catalyst formed a third liquid phase between the organic and inorganic phases. The use of ultrasound provided high yields of organic peroxides (70–99%) in significantly shorter reaction times (1.5 h) in comparison to reaction with magnetic stirring (5.0 h). In turn, conducting the reaction in the tri-liquid PTC system allowed easy separation of the catalyst and its multiple use without significant loss of activity.

APA, Harvard, Vancouver, ISO, and other styles

31

Lewandowski, Grzegorz. "Comparison of the methods of the phase transfer catalysis and hydroperoxide in the epoxidation of 1,5,9-cyclododecatriene." Polish Journal of Chemical Technology 9, no. 3 (January 1, 2007): 101–4. http://dx.doi.org/10.2478/v10026-007-0065-0.

Full text

Abstract:

Comparison of the methods of the phase transfer catalysis and hydroperoxide in the epoxidation of 1,5,9-cyclododecatriene The process of the epoxidation of cis, trans, trans-1,5,9-cyclododecatriene (CDT) to 1,2-epoxy-5,9-cyclododecadiene (ECDD) with the 30% aqueous hydrogen peroxide under the phase transfer conditions and with tert-butyl hydroperoxide under the homogeneous conditions was investigated. Onium salts such as Aliquat® 336, Arquad® 2HT, methyltrioctylammonium bromide and the Na2WO4/H3PO4 catalyst system are very active under the phase transfer catalysis (PTC) conditions for the selective epoxidation of cis, trans, trans-1,5,9-cyclododecatiene (PTC method). These catalytic systems were found to be as active and selective as the homogeneous phase system Mo(CO)6/TBHP (hydroperoxide method).

APA, Harvard, Vancouver, ISO, and other styles

32

Jing, Lu, Guo Qin Liu, Xin Qi Liu, and Xue De Wang. "Synthesis of Epoxidized Soybean Oil via Phase Transfer Catalysis." Advanced Materials Research 690-693 (May 2013): 1061–64. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.1061.

Full text

Abstract:

In the system of heteropoly acid [π-C5H5NC16H33]3[PO4(WO3)4], H2O2 (30 %, w/w), polyethylene glycol, 1,2-dichloroethane, soybean oil under went epoxidation reaction smoothly via reaction-controlled phase transfer catalysis. Effects of the amount of interfacial active agent, H2O2, catalyst and reaction time were investigated and the optimized reaction conditions were as follows: 10 g of soybean oil, 0.3 g of [π-C5H5NC16H33]3[PO4 (WO3)4],8 ml of H2O2 (30 %, w/w), 5.0 ml of PEG, 30 g of 1,2-dichloroethane, and the reaction temperature was 65 °C and reaction time was 3.5-4.0 h. Under these optimized conditions, an epoxy value of 6.30 % and a yield of 90 % were obtained. Hence, it is an environmental-friendly and effective way to synthesize epoxidized soybean oil.

APA, Harvard, Vancouver, ISO, and other styles

33

Lee, Albert W. M., and W. C. Yip. "Fabric softeners as phase transfer catalyst in organic synthesis." Journal of Chemical Education 68, no. 1 (January 1991): 69. http://dx.doi.org/10.1021/ed068p69.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Xie, Xiaofeng, James S. Brown, Paul J. Joseph, Charles L. Liotta, and Charles A. Eckert. "Phase-transfer catalyst separation by CO2 enhanced aqueous extraction." Chemical Communications, no. 10 (April 24, 2002): 1156–57. http://dx.doi.org/10.1039/b200335j.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Leung, Louis M., W. H. Chan, and Sew Koo Leung. "One-step polymerization of polytrithiocarbonate using phase-transfer catalyst." Journal of Polymer Science Part A: Polymer Chemistry 31, no. 7 (June 1993): 1799–806. http://dx.doi.org/10.1002/pola.1993.080310719.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Ido, Tadaatsu, Motohisa Saiki, and Shigeo Goto. "Repeated use of polyethylene glycol as phase transfer catalyst." KAGAKU KOGAKU RONBUNSHU 15, no. 2 (1989): 403–10. http://dx.doi.org/10.1252/kakoronbunshu.15.403.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Yamashita, Haruo. "Molecular Connectivity Index on Design of Phase Transfer Catalyst." KAGAKU KOGAKU RONBUNSHU 18, no. 4 (1992): 549–52. http://dx.doi.org/10.1252/kakoronbunshu.18.549.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

TSANOV, T., R. STAMENOVA, and C. TSVETANOV. "Crosslinked poly(ethylene oxide) as a phase transfer catalyst." Polymer 34, no. 3 (1993): 616–20. http://dx.doi.org/10.1016/0032-3861(93)90559-s.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Anantpinijwatna, Amata, Mauricio Sales-Cruz, Sun Hyung Kim, John P. O’Connell, and Rafiqul Gani. "A systematic modelling framework for phase transfer catalyst systems." Chemical Engineering Research and Design 115 (November 2016): 407–22. http://dx.doi.org/10.1016/j.cherd.2016.07.011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Margi, Nikhil H., and Ganapati D. Yadav. "Design and Development of Novel Continuous Flow Stirred Multiphase Reactor: Liquid–Liquid–Liquid Phase Transfer Catalysed Synthesis of Guaiacol Glycidyl Ether." Processes 8, no. 10 (October 10, 2020): 1271. http://dx.doi.org/10.3390/pr8101271.

Full text

Abstract:

Phase transfer catalysed (PTC) reactions are used in several pharmaceutical and fine chemical industrial processes. We have developed a novel stirred tank reactor (Yadav reactor) to conduct batch and continuous liquid–liquid–liquid (L-L-L) PTC reactions. The reactor had a provision of using three independent stirrers for each phase, thereby having complete control over the rate of mass transfer across the two interfaces. In the continuous mode of operation, the top and bottom phases were continuously fed into the reactor while the middle phase was used as a batch. All three stirrers were used independently, thereby having independent control of mass transfer resistances. The reactor in a batch mode showed higher conversion and selectivity compared to a conventional batch reactor. L-L-L PTC reaction in the continuous mode was successfully performed without loss of the middle catalyst phase and with steady conversion and selectivity. The reaction of guaiacol with epichlorohydrin was conducted as a model reaction, with a 76% conversion of epichlorohydrin, 85% selectivity of guaiacol glycidyl ether, and the middle catalyst phase was stable throughout the process.

APA, Harvard, Vancouver, ISO, and other styles

41

Liang, Yumeng, Mayaka Maeno, Zhengyu Zhao, and Norio Shibata. "Enantioselective Benzylation and Allylation of α-Trifluoromethoxy Indanones under Phase-Transfer Catalysis." Molecules 24, no. 15 (July 30, 2019): 2774. http://dx.doi.org/10.3390/molecules24152774.

Full text

Abstract:

The organo-catalyzed enantioselective benzylation reaction of α-trifluoromethoxy indanones afforded α-benzyl-α-trifluoromethoxy indanones with a tetrasubstituted stereogenic carbon center in excellent yield with moderate enantioselectivity (up to 57% ee). Cinchona alkaloid-based chiral phase transfer catalysts were found to be effective for this transformation, and both enantiomers of α-benzyl-α-trifluoromethoxy indanones were accessed, depended on the use of cinchonidine and cinchonine-derived catalyst. The method was extended to the enantioselective allylation reaction of α-trifluoromethoxy indanones to give the allylation products in moderate yield with good enantioselectivity (up to 76% ee).

APA, Harvard, Vancouver, ISO, and other styles

42

Crasmareanu, Eleonora Cornelia, Vasile Simulescu, and Gheorghe Ilia. "Synthesis by Reversed Phase Transfer Catalysis and Characterization of Naphthol AS-D Pigment." Journal of Chemistry 2013 (2013): 1–4. http://dx.doi.org/10.1155/2013/545374.

Full text

Abstract:

Reversed phase transfer catalysis (RPTC) was applied to synthesize the Naphthol AS-D pigment. This method consists in the transfer of the aryldiazonium cation 4-nitrobenzenediazonium from aqueous medium into the organic phase (nitrobenzene) in the form of a lipophilic ions pair by the catalyst used (perfluorooctyl potassium sulfonates). In the organic phase the azo-coupling reaction between 4-nitrobenzenediazonium chloride and 3-hydroxy-2-carboxylic acid 2-methyl-anilide (Naphthol AS-D) takes place as coupling component. Using this unconventional method of synthesis, an increase of the reaction rate, combined with a higher purity of the product, was obtained.

APA, Harvard, Vancouver, ISO, and other styles

43

El-Sayed, Ahmed M., Omyma A. Abd Allah, Ahmed M. M. El-Saghier, and Shaaban K. Mohamed. "Synthesis and Reactions of Five-Membered Heterocycles Using Phase Transfer Catalyst (PTC) Techniques." Journal of Chemistry 2014 (2014): 1–47. http://dx.doi.org/10.1155/2014/163074.

Full text

Abstract:

Phase transfer catalysts (PTCs) have been widely used for the synthesis of organic compounds particularly in both liquid-liquid and solid-liquid heterogeneous reaction mixtures. They are known to accelerate reaction rates by facilitating formation of interphase transfer of species and making reactions between reagents in two immiscible phases possible. Application of PTC instead of traditional technologies for industrial processes of organic synthesis provides substantial benefits for the environment. On the basis of numerous reports it is evident that phase-transfer catalysis is the most efficient way for generation and reactions of many active intermediates. In this review we report various uses of PTC in syntheses and reactions of five-membered heterocycles compounds and their multifused rings.

APA, Harvard, Vancouver, ISO, and other styles

44

Li, Can, Yiliang Luan, Bo Zhao, Amar Kumbhar, Fan Zhang, and Jiye Fang. "Facile Synthesis of Ceria Nanocrystals with Tuneable Size and Shape." MRS Advances 5, no. 11 (2020): 523–29. http://dx.doi.org/10.1557/adv.2020.25.

Full text

Abstract:

AbstractCeria (CeO2) possesses a distinctive redox property due to a reversible conversion to its nonstoichiometric oxide and has been considered as a promising catalyst in the oxidative coupling of methane. Since a heterogeneously catalytic process usually takes place only on the surface of catalysts, it is reasonably expected that the performance of a catalyst, such as CeO2, highly relies on its size- and shape-dependent surface structure. We report our recent progress in achieving exclusive crystal facet-terminated CeO2 nanocrystals using a shape-controlled synthesis protocol in a one-pot colloidal system. We modified a two-phase solvothermal approach to fabricate cubic and truncated octahedral CeO2 nanocrystals with a size-control. During the two-phase solvothermal process, we propose that the Ce-precursors transfer from the aqueous layer to the interface of the organic phase, promoted by the capping ligands (as known as phase-transfer catalysts), for the oxidation and nucleation, and subsequently form CeO2 nanocrystals in the organic layer. As different capping ligands favor binding on diverse crystal facets, tuning the composition of the capping ligand with a precise control could generate nanocrystals that are dominated by a single type of facets with a relatively narrow size distribution.

APA, Harvard, Vancouver, ISO, and other styles

45

Shi, Xian-Lei, Minli Tao, Huikun Lin, and Wenqin Zhang. "Application of the polyacrylonitrile fiber as a support for the green heterogeneous base catalyst and supported phase-transfer catalyst." RSC Adv. 4, no. 109 (2014): 64347–53. http://dx.doi.org/10.1039/c4ra12069h.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Verbicky, J. W., and E. A. O'Neil. "Chiral phase-transfer catalysis. Enantioselective alkylation of racemic alcohols with a nonfunctionalized optically active phase-transfer catalyst." Journal of Organic Chemistry 50, no. 10 (May 1985): 1786–87. http://dx.doi.org/10.1021/jo00210a054.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Asai, Satoru, Hidemi Nakamura, and Yousuke Furuichi. "The distribution and dissociation equilibria of phase-transfer catalyst tricaprylmethylammonium chloride and its aqueous-phase mass transfer." JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 24, no. 5 (1991): 653–58. http://dx.doi.org/10.1252/jcej.24.653.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Zaraiskii, A. P. "Phase-transfer catalysis in electrophilic substitution reactions: X. A phase-transfer catalyst for an elementary nitration act." Russian Journal of General Chemistry 78, no. 9 (September 2008): 1821. http://dx.doi.org/10.1134/s1070363208090296.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Cibulka, Radek, Lenka Baxová, Hana Dvořáková, František Hampl, Petra Ménová, Viktor Mojr, Baptiste Plancq, and Serkan Sayin. "Catalytic effect of alloxazinium and isoalloxazinium salts on oxidation of sulfides with hydrogen peroxide in micellar media." Collection of Czechoslovak Chemical Communications 74, no. 6 (2009): 973–93. http://dx.doi.org/10.1135/cccc2009030.

Full text

Abstract:

Three novel amphiphilic alloxazinium salts were prepared: 3-dodecyl-5-ethyl-7,8,10-trimethylisoalloxazinium perchlorate (1c), 1-dodecyl-5-ethyl-3-methylalloxazinium perchlorate (2b), and 3-dodecyl-5-ethyl-1-methylalloxazinium perchlorate (2c). Their catalytic activity in thioanisole (3) oxidation with hydrogen peroxide was investigated in micelles of sodium dodecylsulfate (SDS), hexadecyltrimethylammonium nitrate (CTANO3) and Brij 35. Reaction rates were strongly dependent on the catalyst structure, on the type of micelles, and on pH value. Alloxazinium salts 2 were more effective catalysts than isoalloxazinium salts 1. Due to the contribution of micellar catalysis, the vcat/v0 ratio of the catalyzed and non-catalyzed reaction rates was almost 80 with salt 2b solubilized in CTANO3 micelles. Nevertheless, the highest acceleration was observed with non-amphiphilic 5-ethyl-1,3-dimethylalloxazinium perchlorate (2a) in CTANO3 micelles (vcat/v0 = 134). In this case, salt 2a presumably acts as a phase-transfer catalyst bringing hydrogen peroxide from the aqueous phase into the micelle interior. Synthetic applicability of the investigated catalytic systems was verified on semi-preparative scale.

APA, Harvard, Vancouver, ISO, and other styles

50

Matijos̆ka, A., O. Eicher-Lorka, and L. Rastenytė. "Phase Transfer Catalysis Method of Synthesis of Benzyl- and Benzhydryloxyalkoxyalkynes." Journal of Chemical Research 2003, no. 3 (March 2003): 160–61. http://dx.doi.org/10.3184/030823403103173345.

Full text

Abstract:

The synthesis of benzyl- and benzhydryloxyalkoxyalkynes and the determination of the influence of phase transfer catalyst, solvent and temperature on this nucleophilic substitution reaction is reported.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!