HGG (Hydroxypropyl guar gum) was synthesized by phase transfer catalysis for the first time. The effects of alkalinity, phase transfer catalyst, etherification, pH value, temperature, reaction time and stirring spee...HGG (Hydroxypropyl guar gum) was synthesized by phase transfer catalysis for the first time. The effects of alkalinity, phase transfer catalyst, etherification, pH value, temperature, reaction time and stirring speed were investigated. An optimal synthetic reaction technology was established, namely, dose of guar gum is 100 g, propylene oxide 40-50 g, HTAC (hexadecyl trimethyl ammonium chloride ) 1.3-1.7 g, pH value 10-10.5, temperature 45-50℃, and reaction time 3-4 hours. The result shows that the improved HGG has high viscosity. Its dissolution speed, content of insoluble residue, colloid light transparency and stability are apparently superior to guar flour.展开更多
The 1-aryloxyacetyl-4-(4-nitrophenyloxyacetyl)-thiosemicarbazides (3a-h) are synthe- sized via reaction of 4-nitrophenyloxyacetyl chloride with ammonium thiocyanate and aryloxyacetic hydrazides (2a-h) under phase tran...The 1-aryloxyacetyl-4-(4-nitrophenyloxyacetyl)-thiosemicarbazides (3a-h) are synthe- sized via reaction of 4-nitrophenyloxyacetyl chloride with ammonium thiocyanate and aryloxyacetic hydrazides (2a-h) under phase transfer catalysis and microwave irradiation in excellent yield.展开更多
Under the condition of solid-liquid phase transfer catalysis, olefins were obtained by the reaction of p-nitrobenzyldibutyltelluronium bromide with aromatic aldehyde.Under the condition of liquid-liquid phase transfer...Under the condition of solid-liquid phase transfer catalysis, olefins were obtained by the reaction of p-nitrobenzyldibutyltelluronium bromide with aromatic aldehyde.Under the condition of liquid-liquid phase transfer catalysis,however,different products were obtained due to the reactivity of different bases or aldehydes.展开更多
Introduction Microwave irradiation has been very widely used in heating, cooking and brewing. Several papers which describe the use of domestic microwave ovens to perform rapid organic synthesis in solution have been ...Introduction Microwave irradiation has been very widely used in heating, cooking and brewing. Several papers which describe the use of domestic microwave ovens to perform rapid organic synthesis in solution have been published. The high heating efficiency gives rise to remarkable rate of reaction and dramatic reduction of reaction time. Nevertheless, its application seems to be limited to these procedures because of展开更多
A series of new diethers were obtained by alkylation of furoin under microwave irradiation （MWI） in phase transfer catalysis （PTC） conditions. The products of alkyl halides were synthesized in good yields （〉75%...A series of new diethers were obtained by alkylation of furoin under microwave irradiation （MWI） in phase transfer catalysis （PTC） conditions. The products of alkyl halides were synthesized in good yields （〉75%） within a few minutes, and the products of dihalides were synthesized in fair yields （about 45%）. The yields are dramatically improved compared to conventional heating under the same conditions, in spite of similar profiles of rising in temperature.展开更多
Compounds having an active hydroxy group, such as, acyloins can be easily alkylated by alkyl halides in the presence of a phase transfer catalyst （PTC）. The reaction is usually carried out in the presence of con-cen...Compounds having an active hydroxy group, such as, acyloins can be easily alkylated by alkyl halides in the presence of a phase transfer catalyst （PTC）. The reaction is usually carried out in the presence of con-centrated aqueous sodium or potassium hydroxide and a phase transfer catalyst, such as, quaternary ammonium salts^[1-3] species, miscible which facilitate the interphase transfer of making reactions between reagents in two im-phases possible. The reaction involves a series of equilibrium and mass-transfer steps.展开更多
A simple and general method for the synthesis of bi(acyl)disulfides is reported.Sulfur is allowed to react with sodium hydroxide to give sodium disulfide at 65℃ under PTC,which can react with acyl halides to afford b...A simple and general method for the synthesis of bi(acyl)disulfides is reported.Sulfur is allowed to react with sodium hydroxide to give sodium disulfide at 65℃ under PTC,which can react with acyl halides to afford bi(acyl)disulfides in good to excellent isolated yields.The effects of solvents and phase transfer catalysts are discussed.展开更多
In order to overcome the difficulty in stripping and reduce the equilibrium time in heavy rare earth separation with acidic organophosphorous extractants, the phase transfer catalysis (PTC) technique was introduced to...In order to overcome the difficulty in stripping and reduce the equilibrium time in heavy rare earth separation with acidic organophosphorous extractants, the phase transfer catalysis (PTC) technique was introduced to the solvent extraction process, especially applied to the stripping section, which was called phase transfer catalysis stripping (PTCS) process. in the PTCS process, an acidic phosphorous extractant was mixed with another extractant which can transfer hydrogen ion from aqueous phase to organic phase and almost does not extract rare earth ions, so that the stripping efficiency can be improved and the stripping extraction equilibrium be accelerated. The reaction mechanism of the PTCS and the requisite properties for a feasible PTCS catalyst in rare earth extraction were studied. We selected D(2)EHPA as the extractant, Alamine 336 as the PTCS catalyst and mixed rare earth chlorides as the feed to test the PTCS phenomenon. Based on the experimental data, the applicability of PTCS technique in rare earth solvent extraction was discussed.展开更多
Seven diaryl ethers were synthesized with potassium fluoride coated alumina as a strong base and the addition of catalytic amount of PTC. The yield of diaryl ethers with addition of PTC was much higher than that witho...Seven diaryl ethers were synthesized with potassium fluoride coated alumina as a strong base and the addition of catalytic amount of PTC. The yield of diaryl ethers with addition of PTC was much higher than that without PTC.A discussion of the catalysis mechanism was given in this paper.展开更多
The acetylated xylo-and arabinopyranosyl esters(1-8) were obtained in high yields with stereoselectivity by phase-transfer catalyzed (PTC) synthesis, and their structures were confirmed by elemental analysis and IR,^(...The acetylated xylo-and arabinopyranosyl esters(1-8) were obtained in high yields with stereoselectivity by phase-transfer catalyzed (PTC) synthesis, and their structures were confirmed by elemental analysis and IR,^(1)H-NMR spectral data.展开更多
Ethyl N-cyanomethytbenzenecarboximidate reacted with aliphatic aldehydes under the solid-liquid PTC condition to gire a-ethoxyphenylmethylene- aminoacrylonitrile derivatives and oxazoline derivatives.It is a convenien...Ethyl N-cyanomethytbenzenecarboximidate reacted with aliphatic aldehydes under the solid-liquid PTC condition to gire a-ethoxyphenylmethylene- aminoacrylonitrile derivatives and oxazoline derivatives.It is a convenient and new method for synthesis of β,β'-dihyroxy-a-amino acids by hydrolysis of the oxazoline derivatives.展开更多
p nitrophenol is synthesized using p nitrochlorobenzene and sodium hydroxide with phase transfer catalyst. Several reaction factors, such as catalyst type, the amounts of catalysts and sodium hydroxide, the concentrat...p nitrophenol is synthesized using p nitrochlorobenzene and sodium hydroxide with phase transfer catalyst. Several reaction factors, such as catalyst type, the amounts of catalysts and sodium hydroxide, the concentration of sodium hydroxide solution as well as reaction time, affect greatly the yield of p nitrophenol. The optimum reaction conditions are as follows: A 1 used as phase transfer catalyst whose consumption is 6% (mole fraction) of p nitrochlorobenzene; the molar ratio of sodium hydroxide to p nitrochlorobenzene is 3:1; the concentration of sodium hydroxide solution is 50% (mass fraction). Nitrobenzene, whose molar amount is 2.45 times as much as that of p nitrochlorobenzene; reaction time is 7 h at 140 ℃ under normal pressure. The final yield of p nitrophenol is 83.6%.展开更多
Phase transfer catalysis (PTC) has become one of the most extensively used techniques in organic synthesis. The key factor in such processes is the catalyst. There are mainly two kinds of phase transfer catalysts, one...Phase transfer catalysis (PTC) has become one of the most extensively used techniques in organic synthesis. The key factor in such processes is the catalyst. There are mainly two kinds of phase transfer catalysts, one is the so called "crown ethers" including macrocyeles, open chain molecules with long chains, bearing heteroatoms at a proper distance, and can chelate inorganic展开更多
Resorcarens 1a-b (R'=Ph, p-MeOC6H4) were fully alkylated with alkyl iodides or bromides in TEBA/KOH/DMF solid-liquid PTC process with 63-82% yields, whereas the three calix[4]pyrroles 3a-b (2R= 2Me, (CH2)(4), (CH2...Resorcarens 1a-b (R'=Ph, p-MeOC6H4) were fully alkylated with alkyl iodides or bromides in TEBA/KOH/DMF solid-liquid PTC process with 63-82% yields, whereas the three calix[4]pyrroles 3a-b (2R= 2Me, (CH2)(4), (CH2)(5)) were alkylated with alkyl iodides in TBAB/ 50%NaOH/ CH2Cl2 liquid-liquid PTC system with lower yields (10-38%).展开更多
An efficient and enantioselective aerobic oxidation of 4-substituted pyrazolones has been developed by phase transfer catalysis.Using visible light as the driving force and O_(2)(in air)as the oxidant,broad scopes(38 ...An efficient and enantioselective aerobic oxidation of 4-substituted pyrazolones has been developed by phase transfer catalysis.Using visible light as the driving force and O_(2)(in air)as the oxidant,broad scopes(38 examples)of pyrazolones bearing an oxygen-attached carbon stereocenter at C-4 position were obtained in high yields(up to 98%)and excellent enantioselectivities(up to 93%ee)under mid conditions.The ready availability of catalyst,ease of operation,and low-cost and eco-friendly nature highlighted the practical utility of this visible lightpromoted enantioselective aerobic oxidation.展开更多
Oxidative coupling of α-bromoarylacetonitriles and oxidative decyanation of diarylacetonitriles are efficiently realized by solid-liquid phase transfer catalysis using anhydrous K 3 PO 4 as base and TBAB as catalyst ...Oxidative coupling of α-bromoarylacetonitriles and oxidative decyanation of diarylacetonitriles are efficiently realized by solid-liquid phase transfer catalysis using anhydrous K 3 PO 4 as base and TBAB as catalyst in acetone at room temperature. In this mild and convenient method, α,β-dicyanostilbenes and diarylketones were prepared in good to excellent yields.展开更多
Several thiourea polymers have been synthesized through the reaction of diamine with 1, 4- or 1, 3- benzenedicarbonyl chloride and ammonium thiocyanate by solid-liquid phase transfer catalysis of polyethylene glycol-4...Several thiourea polymers have been synthesized through the reaction of diamine with 1, 4- or 1, 3- benzenedicarbonyl chloride and ammonium thiocyanate by solid-liquid phase transfer catalysis of polyethylene glycol-400 (PEG-400). The polymers were characterized and identified by elemental analysis, IR, 1HNMR and GPC. The multifunctional polymers have potential value as an ideal support for immobilized enzymes.展开更多
Introduction Recently more attention has been paid to the application of sulfones to organic synthesis. Because the arylsulfonyl groups can stabilize adjacent carbanions and may be removed by reduction and elimination...Introduction Recently more attention has been paid to the application of sulfones to organic synthesis. Because the arylsulfonyl groups can stabilize adjacent carbanions and may be removed by reduction and elimination, the arylsulfonyl groups could be used as activating group for alkylation, acvlation or addition reaction.展开更多
The title compound, thiodiglycol dimethacrylate (TDGDMA), was synthesized from thiodiglycol and methacryloyl chloride by phase transfer catalysis reaction, and its structure was confirmed by FTIR and 1H-NMR analyses. ...The title compound, thiodiglycol dimethacrylate (TDGDMA), was synthesized from thiodiglycol and methacryloyl chloride by phase transfer catalysis reaction, and its structure was confirmed by FTIR and 1H-NMR analyses. TDGDMA possesses good polymerizability to produce a homopolymer resin with excellent transparency (T%, 90), moderate refractivity (nd20, 1.55), lower dispersivity (Abbe's number, 50.6) and higher glass transition temperature (Tg, 119°C). Through copolymerization with styrene (St) or styrene-4,4'-bismethacryloyloxydiphenylsulfone (BPSDMA), many properties of the copolymer such as refractive index, Abbe's number, strength, onset wavelength in the UV region and density were significantly modified. A copolymer resin with balanced properties between refractive index and dispersion was produced at the weight ratio of TDGDMA:St:BPSDMA (25:50:25), where nd20 and Abbe's number are 1.5815 and 36.5, respectively.展开更多
Introduction 5-Monosubstituted isopropylidene malonates arc important synthetic organic intermediates. Since isopropylidene malonate has a stronger acidity （pK;=4.57）, its direct alkylation with alkyl halides usuall...Introduction 5-Monosubstituted isopropylidene malonates arc important synthetic organic intermediates. Since isopropylidene malonate has a stronger acidity （pK;=4.57）, its direct alkylation with alkyl halides usually gives 5,5-disubstitutcd isopropylidene malonates.展开更多
文摘HGG (Hydroxypropyl guar gum) was synthesized by phase transfer catalysis for the first time. The effects of alkalinity, phase transfer catalyst, etherification, pH value, temperature, reaction time and stirring speed were investigated. An optimal synthetic reaction technology was established, namely, dose of guar gum is 100 g, propylene oxide 40-50 g, HTAC (hexadecyl trimethyl ammonium chloride ) 1.3-1.7 g, pH value 10-10.5, temperature 45-50℃, and reaction time 3-4 hours. The result shows that the improved HGG has high viscosity. Its dissolution speed, content of insoluble residue, colloid light transparency and stability are apparently superior to guar flour.
基金Technological Innovation Engineering of Northwest Normal University (NWNU-KJCXGC-218) Natural Science Foundation of Gansu Province and Youth Foundation of Northwest Normal University.
文摘The 1-aryloxyacetyl-4-(4-nitrophenyloxyacetyl)-thiosemicarbazides (3a-h) are synthe- sized via reaction of 4-nitrophenyloxyacetyl chloride with ammonium thiocyanate and aryloxyacetic hydrazides (2a-h) under phase transfer catalysis and microwave irradiation in excellent yield.
文摘Under the condition of solid-liquid phase transfer catalysis, olefins were obtained by the reaction of p-nitrobenzyldibutyltelluronium bromide with aromatic aldehyde.Under the condition of liquid-liquid phase transfer catalysis,however,different products were obtained due to the reactivity of different bases or aldehydes.
文摘Introduction Microwave irradiation has been very widely used in heating, cooking and brewing. Several papers which describe the use of domestic microwave ovens to perform rapid organic synthesis in solution have been published. The high heating efficiency gives rise to remarkable rate of reaction and dramatic reduction of reaction time. Nevertheless, its application seems to be limited to these procedures because of
基金Natural Science Foundation of Jilin Province, China （No. 1999010540）.
文摘A series of new diethers were obtained by alkylation of furoin under microwave irradiation （MWI） in phase transfer catalysis （PTC） conditions. The products of alkyl halides were synthesized in good yields （〉75%） within a few minutes, and the products of dihalides were synthesized in fair yields （about 45%）. The yields are dramatically improved compared to conventional heating under the same conditions, in spite of similar profiles of rising in temperature.
基金Supported by the Natural Science Foundation of Jilin Province,China(No.1999010540).
文摘Compounds having an active hydroxy group, such as, acyloins can be easily alkylated by alkyl halides in the presence of a phase transfer catalyst （PTC）. The reaction is usually carried out in the presence of con-centrated aqueous sodium or potassium hydroxide and a phase transfer catalyst, such as, quaternary ammonium salts^[1-3] species, miscible which facilitate the interphase transfer of making reactions between reagents in two im-phases possible. The reaction involves a series of equilibrium and mass-transfer steps.
文摘A simple and general method for the synthesis of bi(acyl)disulfides is reported.Sulfur is allowed to react with sodium hydroxide to give sodium disulfide at 65℃ under PTC,which can react with acyl halides to afford bi(acyl)disulfides in good to excellent isolated yields.The effects of solvents and phase transfer catalysts are discussed.
文摘In order to overcome the difficulty in stripping and reduce the equilibrium time in heavy rare earth separation with acidic organophosphorous extractants, the phase transfer catalysis (PTC) technique was introduced to the solvent extraction process, especially applied to the stripping section, which was called phase transfer catalysis stripping (PTCS) process. in the PTCS process, an acidic phosphorous extractant was mixed with another extractant which can transfer hydrogen ion from aqueous phase to organic phase and almost does not extract rare earth ions, so that the stripping efficiency can be improved and the stripping extraction equilibrium be accelerated. The reaction mechanism of the PTCS and the requisite properties for a feasible PTCS catalyst in rare earth extraction were studied. We selected D(2)EHPA as the extractant, Alamine 336 as the PTCS catalyst and mixed rare earth chlorides as the feed to test the PTCS phenomenon. Based on the experimental data, the applicability of PTCS technique in rare earth solvent extraction was discussed.
文摘Seven diaryl ethers were synthesized with potassium fluoride coated alumina as a strong base and the addition of catalytic amount of PTC. The yield of diaryl ethers with addition of PTC was much higher than that without PTC.A discussion of the catalysis mechanism was given in this paper.
文摘The acetylated xylo-and arabinopyranosyl esters(1-8) were obtained in high yields with stereoselectivity by phase-transfer catalyzed (PTC) synthesis, and their structures were confirmed by elemental analysis and IR,^(1)H-NMR spectral data.
基金The project supported by the National Natural Science Foundation of China.Present Address:Shanghai Institute of Organic Chemistry,Academia Sinica.
文摘Ethyl N-cyanomethytbenzenecarboximidate reacted with aliphatic aldehydes under the solid-liquid PTC condition to gire a-ethoxyphenylmethylene- aminoacrylonitrile derivatives and oxazoline derivatives.It is a convenient and new method for synthesis of β,β'-dihyroxy-a-amino acids by hydrolysis of the oxazoline derivatives.
文摘p nitrophenol is synthesized using p nitrochlorobenzene and sodium hydroxide with phase transfer catalyst. Several reaction factors, such as catalyst type, the amounts of catalysts and sodium hydroxide, the concentration of sodium hydroxide solution as well as reaction time, affect greatly the yield of p nitrophenol. The optimum reaction conditions are as follows: A 1 used as phase transfer catalyst whose consumption is 6% (mole fraction) of p nitrochlorobenzene; the molar ratio of sodium hydroxide to p nitrochlorobenzene is 3:1; the concentration of sodium hydroxide solution is 50% (mass fraction). Nitrobenzene, whose molar amount is 2.45 times as much as that of p nitrochlorobenzene; reaction time is 7 h at 140 ℃ under normal pressure. The final yield of p nitrophenol is 83.6%.
基金Supported by the National Natureal Science Fomentation of Chinathe National Education Commission Foundation of China
文摘Phase transfer catalysis (PTC) has become one of the most extensively used techniques in organic synthesis. The key factor in such processes is the catalyst. There are mainly two kinds of phase transfer catalysts, one is the so called "crown ethers" including macrocyeles, open chain molecules with long chains, bearing heteroatoms at a proper distance, and can chelate inorganic
文摘Resorcarens 1a-b (R'=Ph, p-MeOC6H4) were fully alkylated with alkyl iodides or bromides in TEBA/KOH/DMF solid-liquid PTC process with 63-82% yields, whereas the three calix[4]pyrroles 3a-b (2R= 2Me, (CH2)(4), (CH2)(5)) were alkylated with alkyl iodides in TBAB/ 50%NaOH/ CH2Cl2 liquid-liquid PTC system with lower yields (10-38%).
基金We would like to thank the University Key Research Projects of Henan Province(No.19A350009)Natural Science Foundation of Henan Province(No.202300410321)for their support.
文摘An efficient and enantioselective aerobic oxidation of 4-substituted pyrazolones has been developed by phase transfer catalysis.Using visible light as the driving force and O_(2)(in air)as the oxidant,broad scopes(38 examples)of pyrazolones bearing an oxygen-attached carbon stereocenter at C-4 position were obtained in high yields(up to 98%)and excellent enantioselectivities(up to 93%ee)under mid conditions.The ready availability of catalyst,ease of operation,and low-cost and eco-friendly nature highlighted the practical utility of this visible lightpromoted enantioselective aerobic oxidation.
基金Natural Science Foundation of China (Grant No.NSFC 20672009)
文摘Oxidative coupling of α-bromoarylacetonitriles and oxidative decyanation of diarylacetonitriles are efficiently realized by solid-liquid phase transfer catalysis using anhydrous K 3 PO 4 as base and TBAB as catalyst in acetone at room temperature. In this mild and convenient method, α,β-dicyanostilbenes and diarylketones were prepared in good to excellent yields.
基金This project is supported by the National Natural Science Foundation of China(Contract grant number:29872061,20032020).
文摘Several thiourea polymers have been synthesized through the reaction of diamine with 1, 4- or 1, 3- benzenedicarbonyl chloride and ammonium thiocyanate by solid-liquid phase transfer catalysis of polyethylene glycol-400 (PEG-400). The polymers were characterized and identified by elemental analysis, IR, 1HNMR and GPC. The multifunctional polymers have potential value as an ideal support for immobilized enzymes.
基金Supported by the Natural Science Foundation of Zhejiang Province
文摘Introduction Recently more attention has been paid to the application of sulfones to organic synthesis. Because the arylsulfonyl groups can stabilize adjacent carbanions and may be removed by reduction and elimination, the arylsulfonyl groups could be used as activating group for alkylation, acvlation or addition reaction.
基金This project was supported by the Natural Science Foundation of Zhejiang Province (599103).
文摘The title compound, thiodiglycol dimethacrylate (TDGDMA), was synthesized from thiodiglycol and methacryloyl chloride by phase transfer catalysis reaction, and its structure was confirmed by FTIR and 1H-NMR analyses. TDGDMA possesses good polymerizability to produce a homopolymer resin with excellent transparency (T%, 90), moderate refractivity (nd20, 1.55), lower dispersivity (Abbe's number, 50.6) and higher glass transition temperature (Tg, 119°C). Through copolymerization with styrene (St) or styrene-4,4'-bismethacryloyloxydiphenylsulfone (BPSDMA), many properties of the copolymer such as refractive index, Abbe's number, strength, onset wavelength in the UV region and density were significantly modified. A copolymer resin with balanced properties between refractive index and dispersion was produced at the weight ratio of TDGDMA:St:BPSDMA (25:50:25), where nd20 and Abbe's number are 1.5815 and 36.5, respectively.
基金Supported by the National Natural Science Foundation of Chinathe Basic Research Foundation of Zhejian Educational Commission.
文摘Introduction 5-Monosubstituted isopropylidene malonates arc important synthetic organic intermediates. Since isopropylidene malonate has a stronger acidity （pK;=4.57）, its direct alkylation with alkyl halides usually gives 5,5-disubstitutcd isopropylidene malonates.
