A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the ...A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the product stream containing ethylbenzene was used to heat the reactor vessel, which consisted of an alkylation section, an upper heat exchange section, and a bottom heat exchange section. In such a novel reactor, vapor phase benzene and liquid phase benzene were coexisted due to the heat produced by isothermal reaction between the upper heat exchange section and the bottom heat exchange section. The process was demonstrated by the thermodynamic analysis and experimental results. In fact, during the 1010 hour-life-test of gas phase ethene with gas phase-liquid phase benzene alkylation reaction, the ethene conversion was above 95%, and the ethylbenzene selectivity was above 83% （only benzene feed） and even higher than 99% （benzene plus transalkylation feed）. At the same time, the xylene content in the ethylbenzene was less than 100 ppm when the reaction was carried out under the reaction conditions of 140-185℃ of temperature, 1.6-2.1 MPa of pressure, 3.0-5.5 of benzene/ethylene mole ratio, 4-6 v% of transalkylation feed/（benzene＋transalkylation feed）, 0.19-0.27 h^-1 of ethene space velocity, and 1000 g of 3998 catalyst loaded. Thus, compared with the conventional ethylbenzene synthesis route, the transalkylation reactor could be omitted in this novel industrial process.展开更多
The alkylation of methylnaphthalene（MN） with methanol in the presence of HZSM-5 is a promising route for producing 2,6-dimetylnaphthalene（2,6-DMN） with a high selectivity. However, the conversion of MN is very low...The alkylation of methylnaphthalene（MN） with methanol in the presence of HZSM-5 is a promising route for producing 2,6-dimetylnaphthalene（2,6-DMN） with a high selectivity. However, the conversion of MN is very low and the catalyst will be deactivated rapidly with increasing time on stream. In this study, the effects of the reaction pressure on the reactivity, selectivity and life of the catalyst of alkylation of MN over HZSM-5 modified by BaO were investigated. It was observed that with the enhancement of pressure, the conversion of MN increased, but the selectivity of 2,6-DMN kept unchanged, which was about 40% -42%. When the alkylation was carried out under a supercritical condition, the conversion of MN was 3-6 times higher and the life of catalyst was 25-30 times longer than those at an ambient pressure. The thermogravimetric analyses of the deactivated catalysts at different reaction pressures indicate that the amount of coke deposited on the catalysts was about 10% to 12 %, and the coke-burning reactions mainly took place in a temperature range from 720 to 860 K, and the apparent activation energies of the coke-burning catalysts at 0. 1 MPa（ 10 h） and 7. 6 MPa（ 108 h） were, respectively, 65.90 and 84. 72 kJ/mol. It is concluded from tile results that the supercritical condition is advantageous to enhancing the conversion of alkylation and extraction in situ, and to transporting those high molecular-weight poly-aromatic compounds so as to extend the catalyst life successively.展开更多
Ionic liquids （ILs） based on 1,3-dialkylimidazolium and tetraalkylammonium cations were employed as a series of efficient, environmentally benign phase-transfer catalysts （PTCs） for the base-promoted monoalkylatio...Ionic liquids （ILs） based on 1,3-dialkylimidazolium and tetraalkylammonium cations were employed as a series of efficient, environmentally benign phase-transfer catalysts （PTCs） for the base-promoted monoalkylation of diethyl malonate. The influence of various heterogeneous bases on yields was studied. Good yields and high selectivity were obtained. Solvent-free, mild reaction condition, short reaction time, and easy purification were the merits of this method. The catalytic system （IL-hase） could also be recycled after the extraction of products with ether.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
Solid superacid perfluorooctanesulfonic acid(POSA)catalyzed Friedel-Crafts alkylation of aromatic hydrocarbons with olefins in gas-liquid phase.The alkylations gave good yields with simple operation and easy work up.T...Solid superacid perfluorooctanesulfonic acid(POSA)catalyzed Friedel-Crafts alkylation of aromatic hydrocarbons with olefins in gas-liquid phase.The alkylations gave good yields with simple operation and easy work up.The amount of the catalyst used in the reactions was small and could be reused.The optimum temperature of the reactions and the effect of the amount of the catalyst used in the reactions are also discussed.展开更多
A convenient synthetic approach leading to protected inositol was described based on regioselective O-alkylation using alkyl halide under solid-liquid PTC condition
A simple and environmentally friendly method is described for the efficient conversion of alkyl halide to alkyl thiocyanate using tetrabutylammonium bromide （TBAB） as a phase transfer catalyst. The reactions occur i...A simple and environmentally friendly method is described for the efficient conversion of alkyl halide to alkyl thiocyanate using tetrabutylammonium bromide （TBAB） as a phase transfer catalyst. The reactions occur in water and furnish the corresponding alkyl thiocyanate in high yields. No evidence for the formation of isothiocyanates as by-product of the reaction was observed and the products were obtained in pure form without further purification.展开更多
The three-phase behavior in the quaternary system of an alkyl (C8/10- or C12/14-) polyglucoside / 1-butanol / n-octane / water has been studied at 40 ℃ with the modified fishlike phase diagram, which is presented by ...The three-phase behavior in the quaternary system of an alkyl (C8/10- or C12/14-) polyglucoside / 1-butanol / n-octane / water has been studied at 40 ℃ with the modified fishlike phase diagram, which is presented by us for the first time. The mass fraction of 1-butanol in the hydrophile-lipophile balanced interfacial layer, AS, the coordinates of the start point B and the end point E of the phase diagram, and the solubilities of alkyl polyglucoside and 1-butanol in n-octane phase were calculated. The solubilization of the microemulsion was also discussed.展开更多
Five novel bis—(N—alkyl—N,N—dimethyl ammoni(?)n)polyethyleneglyool ether salts prepared by our previously reported proced(?)e show high catalytic efficiency in the condensation of 1,4—diacetyl— 2,5—piperazinedi...Five novel bis—(N—alkyl—N,N—dimethyl ammoni(?)n)polyethyleneglyool ether salts prepared by our previously reported proced(?)e show high catalytic efficiency in the condensation of 1,4—diacetyl— 2,5—piperazinedione and aldehydes at both higher and lower temperature even in lower concentration.They al so show catalytic selectivity at lower temperature.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
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 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
We report here a solid-phase synthesis of 1, 4-disubstituted 1, 2, 3-triazole using polystyrene-supported selenium resin. The resin used here not only works as a simple linker, but also assists the crucial α-alkylati...We report here a solid-phase synthesis of 1, 4-disubstituted 1, 2, 3-triazole using polystyrene-supported selenium resin. The resin used here not only works as a simple linker, but also assists the crucial α-alkylation reaction and selenoxide syn-elimimation, which ensures the purity of the products.展开更多
基金This work is supported by the National 973 Project of China (2009CB623501)
文摘A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the product stream containing ethylbenzene was used to heat the reactor vessel, which consisted of an alkylation section, an upper heat exchange section, and a bottom heat exchange section. In such a novel reactor, vapor phase benzene and liquid phase benzene were coexisted due to the heat produced by isothermal reaction between the upper heat exchange section and the bottom heat exchange section. The process was demonstrated by the thermodynamic analysis and experimental results. In fact, during the 1010 hour-life-test of gas phase ethene with gas phase-liquid phase benzene alkylation reaction, the ethene conversion was above 95%, and the ethylbenzene selectivity was above 83% （only benzene feed） and even higher than 99% （benzene plus transalkylation feed）. At the same time, the xylene content in the ethylbenzene was less than 100 ppm when the reaction was carried out under the reaction conditions of 140-185℃ of temperature, 1.6-2.1 MPa of pressure, 3.0-5.5 of benzene/ethylene mole ratio, 4-6 v% of transalkylation feed/（benzene＋transalkylation feed）, 0.19-0.27 h^-1 of ethene space velocity, and 1000 g of 3998 catalyst loaded. Thus, compared with the conventional ethylbenzene synthesis route, the transalkylation reactor could be omitted in this novel industrial process.
文摘The alkylation of methylnaphthalene（MN） with methanol in the presence of HZSM-5 is a promising route for producing 2,6-dimetylnaphthalene（2,6-DMN） with a high selectivity. However, the conversion of MN is very low and the catalyst will be deactivated rapidly with increasing time on stream. In this study, the effects of the reaction pressure on the reactivity, selectivity and life of the catalyst of alkylation of MN over HZSM-5 modified by BaO were investigated. It was observed that with the enhancement of pressure, the conversion of MN increased, but the selectivity of 2,6-DMN kept unchanged, which was about 40% -42%. When the alkylation was carried out under a supercritical condition, the conversion of MN was 3-6 times higher and the life of catalyst was 25-30 times longer than those at an ambient pressure. The thermogravimetric analyses of the deactivated catalysts at different reaction pressures indicate that the amount of coke deposited on the catalysts was about 10% to 12 %, and the coke-burning reactions mainly took place in a temperature range from 720 to 860 K, and the apparent activation energies of the coke-burning catalysts at 0. 1 MPa（ 10 h） and 7. 6 MPa（ 108 h） were, respectively, 65.90 and 84. 72 kJ/mol. It is concluded from tile results that the supercritical condition is advantageous to enhancing the conversion of alkylation and extraction in situ, and to transporting those high molecular-weight poly-aromatic compounds so as to extend the catalyst life successively.
文摘Ionic liquids （ILs） based on 1,3-dialkylimidazolium and tetraalkylammonium cations were employed as a series of efficient, environmentally benign phase-transfer catalysts （PTCs） for the base-promoted monoalkylation of diethyl malonate. The influence of various heterogeneous bases on yields was studied. Good yields and high selectivity were obtained. Solvent-free, mild reaction condition, short reaction time, and easy purification were the merits of this method. The catalytic system （IL-hase） could also be recycled after the extraction of products with ether.
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%).
文摘Solid superacid perfluorooctanesulfonic acid(POSA)catalyzed Friedel-Crafts alkylation of aromatic hydrocarbons with olefins in gas-liquid phase.The alkylations gave good yields with simple operation and easy work up.The amount of the catalyst used in the reactions was small and could be reused.The optimum temperature of the reactions and the effect of the amount of the catalyst used in the reactions are also discussed.
文摘A convenient synthetic approach leading to protected inositol was described based on regioselective O-alkylation using alkyl halide under solid-liquid PTC condition
基金Partial support for this work by Chamran University Research Council is gratefully acknowledged.
文摘A simple and environmentally friendly method is described for the efficient conversion of alkyl halide to alkyl thiocyanate using tetrabutylammonium bromide （TBAB） as a phase transfer catalyst. The reactions occur in water and furnish the corresponding alkyl thiocyanate in high yields. No evidence for the formation of isothiocyanates as by-product of the reaction was observed and the products were obtained in pure form without further purification.
文摘The three-phase behavior in the quaternary system of an alkyl (C8/10- or C12/14-) polyglucoside / 1-butanol / n-octane / water has been studied at 40 ℃ with the modified fishlike phase diagram, which is presented by us for the first time. The mass fraction of 1-butanol in the hydrophile-lipophile balanced interfacial layer, AS, the coordinates of the start point B and the end point E of the phase diagram, and the solubilities of alkyl polyglucoside and 1-butanol in n-octane phase were calculated. The solubilization of the microemulsion was also discussed.
文摘Five novel bis—(N—alkyl—N,N—dimethyl ammoni(?)n)polyethyleneglyool ether salts prepared by our previously reported proced(?)e show high catalytic efficiency in the condensation of 1,4—diacetyl— 2,5—piperazinedione and aldehydes at both higher and lower temperature even in lower concentration.They al so show catalytic selectivity at lower temperature.
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.
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the National Natural Science Foundation of China(No.20332060)the Natural Science Foundation of Zhejiang Province(No.Y405407).
文摘We report here a solid-phase synthesis of 1, 4-disubstituted 1, 2, 3-triazole using polystyrene-supported selenium resin. The resin used here not only works as a simple linker, but also assists the crucial α-alkylation reaction and selenoxide syn-elimimation, which ensures the purity of the products.
