The vapor-liquid equilibrium data of four binary systems (acetic acid +p-xylene, methyl acetate +n-propyl acetate, n-propyl acetate +p-xylene and methyl acetate +p-xylene) are measured at 101.33 kPa with Ellis equilib...The vapor-liquid equilibrium data of four binary systems (acetic acid +p-xylene, methyl acetate +n-propyl acetate, n-propyl acetate +p-xylene and methyl acetate +p-xylene) are measured at 101.33 kPa with Ellis equilibrium still, and then both the NRTL and UNIQUAC models are used in combination with the HOC model for correlating and estimating the vapor-liquid equilibrium of these four binary systems. The estimated binary VLE results using correlated parameters agree well with the measured data except the methyl acetate +p-xylene system which easily causes bumping and liquid rushing out of the sampling tap due to their dramatically different boiling points. The correlation results by NRTL and UNIQUAC models have little difference on the average absolute deviations of temperature and composition of vapor phase, and the results by NRTL model are slightly better than those by UNIQUAC model except for the methyl acetate +n-propyl acetate system, for which the latter gives more accurate correlations.展开更多
The alkylation of toluene with methanol to selective formation of p-xylene has been systematically studied. ZSM-12 （MTW）/ZSM-5 co-crystalline zeolite in 40：60 proportions have been synthesized by the same molar gel...The alkylation of toluene with methanol to selective formation of p-xylene has been systematically studied. ZSM-12 （MTW）/ZSM-5 co-crystalline zeolite in 40：60 proportions have been synthesized by the same molar gel composition, but at different temperatures and periods than that of ZSM-12 and ZSM-5, separately. All the prepared samples are characterized by XRD, SEM, BET, and XRF. The activity of toluene alkylation was investigated with a mixture of toluene and methanol as a feed over the ZSM-12, ZSM-12/ZSM-5 co-crystalline, ZSM-5, and physical mixture of ZSM-12/ZSM-5. From characterization, it is observed that the ZSM-12/ZSM-5 co-crystalline material is different from that of ZSM-12, ZSM-5, and their physical mixture. Further, the ZSM-12/ZSM-5 co-crystalline zeolite produces the highest content of xylene and has better selectivity for p-xylene than ZSM-12, ZSM-5, and their physical mixture.展开更多
The alkylation of toluene with methanol for the selective formation of p-xylene was systematically studied. Very few studies have been reported on the use of superacids such as heteropolyacids on cheap supports, such ...The alkylation of toluene with methanol for the selective formation of p-xylene was systematically studied. Very few studies have been reported on the use of superacids such as heteropolyacids on cheap supports, such as clay. This article deals with the use of different heteropoly acids （HPAs）, viz, Dodeca-Tungstophosphoric acid [H3PO4.12WO3.xH2O] （TPA）, Dodeca-Molyhdo phosphoric acid ammonium salt hydrate [H12Mo12N3O40P＋aq] （DMAA）, Dodeca-Molyhdo Phosphoric acid （PMA） on clay （MontmoriUonite, K-10） and as such plain clay. This comparative study reveals that 20%PMA/Clay shows 62% toluene conversion and 100% selectivity toward p-xylene.展开更多
The global consumption of p-xylene(PX)for the production of polymers has raised serious concerns about its impact on the environment.As various reports have shown the risks that PX could pose to human health,research ...The global consumption of p-xylene(PX)for the production of polymers has raised serious concerns about its impact on the environment.As various reports have shown the risks that PX could pose to human health,research into cost-effective remedial methods to remove PX from the environment has gained attraction.In this work,a hierarchical porous crab shell biochar(KCS)was synthesized,characterized,and evaluated for its efficiency to remove PX from aqueous solution.The characterizations of KCS,including the porous structure,surface functional group,phase structure,and surface morphology,were discussed by N_(2) adsorption-desorption,FTIR,XRD,and SEM.Batch adsorption experiments showed that the maximum adsorption capacity of PX on KCS was 393 mg/g within 5 min,larger than most biological/biomass materials,mainly due to the higher specific surface area of 2046 m^(2)/g,and abundant lipophilic functional groups.Subsequent adsorption kinetics study indicated a pseudo-second-order model which implied that the adsorption of PX was due to chemisorption.Thermodynamic parameters showed that the values ofΔH°andΔG°were both negative,indicating that the PX adsorption process on KCS was spontaneous and exothermic.The performance of KCS in delivering a cost-effective,fast,and efficient solution for the removal of PX from aqueous solution would greatly benefit current environmental remediation efforts.展开更多
During the liquid-phase oxidation of p-xylene,over-oxidation of reactant,intermediates and solvent to carbon dioxide and carbon monoxide is generally known as the burning side reaction.Batch and semi-continuous experi...During the liquid-phase oxidation of p-xylene,over-oxidation of reactant,intermediates and solvent to carbon dioxide and carbon monoxide is generally known as the burning side reaction.Batch and semi-continuous experiments were carried out,and the experimental data of the burning side reaction were analyzed and reported in this paper.The results showed that the rates of burning side reactions were proportional to the rates of the main reaction,but decreased with the increasing concentrations of reactant and intermediates.The inter-stimulative and competitive relationship between the burning side reaction and the main reaction was confirmed,and the rates of the burning side reaction could be described with some key indexes of the main reaction.According to the mechanism of the side reactions and the kinetics model of main reaction which were proposed and tested in the previous papers,a kinetic model of the burning side reactions involving some key indexes of the main reaction was developed,and the parameters were determined by data fitting of the COx rate curves.The obtained kinetic model could describe the burning side reactions adequately.展开更多
The viscosities of pure water,the acetic acid+water binary system,and the p-xylene+acetic acid+ water ternary system at different concentrations were determined with a rolling-ball viscometer at temperatures from 313....The viscosities of pure water,the acetic acid+water binary system,and the p-xylene+acetic acid+ water ternary system at different concentrations were determined with a rolling-ball viscometer at temperatures from 313.15 to 473.15 K and pressures from 0.10 to 3.20 MPa.The viscosity data were fitted by a correlation equation for the estimation of the mixture viscosities.The average absolute deviations(AAD)of the correlation for binary and ternary systems are 2.48%and 1.77%,respectively.展开更多
In recent years, immune genetic algorithm (IGA) is gaining popularity for finding the optimal solution for non-linear optimization problems in many engineering applications. However, IGA with deterministic mutation fa...In recent years, immune genetic algorithm (IGA) is gaining popularity for finding the optimal solution for non-linear optimization problems in many engineering applications. However, IGA with deterministic mutation factor suffers from the problem of premature convergence. In this study, a modified self-adaptive immune genetic algorithm (MSIGA) with two memory bases, in which immune concepts are applied to determine the mutation parameters, is proposed to improve the searching ability of the algorithm and maintain population diversity. Performance comparisons with other well-known population-based iterative algorithms show that the proposed method converges quickly to the global optimum and overcomes premature problem. This algorithm is applied to optimize a feed forward neural network to measure the content of products in the combustion side reaction of p-xylene oxidation, and satisfactory results are obtained.展开更多
This work developed a one-step process for renewable p-xylene production by co-catalytic fast pyrolysis (co-CFP) of cellulose and methanol over the different metal oxides modified ZSM5 catalysts. It has been proven th...This work developed a one-step process for renewable p-xylene production by co-catalytic fast pyrolysis (co-CFP) of cellulose and methanol over the different metal oxides modified ZSM5 catalysts. It has been proven that La2O3-modified ZSM5(80) catalyst was an effective one for the production of biobased p-xylene. The selectivity and yield of p-xylene strongly depended on the acidity of the catalysts, reaction temperature, and methanol content. The highest p-xylene yield of 14.5 C-mol% with a p-xylene/xylenes ratio of 86.8% was obtained by the co-CFP of cellulose with 33wt% methanol over 20%La2O3-ZSM5(80) catalyst. The deactivation of the catalysts during the catalytic pyrolysis process was investigated in detail.The reaction pathway for the formation of p-xylene from cellulose was proposed based on the analysis of products and the characterization of catalysts.展开更多
The rise in the use of global polyester fiber contributed to strong demand of the Terephthalic acid （TPA）. The liquid-phase catalytic oxidation of p-xylene （PX） to TPA is regarded as a critical and efficient chemi...The rise in the use of global polyester fiber contributed to strong demand of the Terephthalic acid （TPA）. The liquid-phase catalytic oxidation of p-xylene （PX） to TPA is regarded as a critical and efficient chemical process in industry [ 1 ]. PX oxidation reaction involves many complex side reactions, among which acetic acid combustion and PX combustion are the most important. As the target product of this oxidation process, the quality and yield of TPA are of great concern. However, the improvement of the qualified product yield can bring about the high energy consumption, which means that the economic objectives of this process cannot be achieved simulta- neously because the two objectives are in conflict with each other. In this paper, an improved self-adaptive multi-objective differential evolution algorithm was proposed to handle the multi-objective optimization prob- lems. The immune concept is introduced to the self-adaptive multi-objective differential evolution algorithm （SADE） to strengthen the local search ability and optimization accuracy. The proposed algorithm is successfully tested on several benchmark test problems, and the performance measures such as convergence and divergence metrics are calculated. Subsequently, the multi-objective optimization of an industrial PX oxidation process is carried out using the proposed immune self-adaptive multi-objective differential evolution algorithm （ISADE）. Optimization results indicate that application oflSADE can greatly improve the yield of TPA with low combustion loss without degenerating TA quality.展开更多
Purified terephthalic acid(PTA) is an important chemical raw material. P-xylene(PX) is transformed to terephthalic acid(TA) through oxidation process and TA is refined to produce PTA. The PX oxidation reaction is a co...Purified terephthalic acid(PTA) is an important chemical raw material. P-xylene(PX) is transformed to terephthalic acid(TA) through oxidation process and TA is refined to produce PTA. The PX oxidation reaction is a complex process involving three-phase reaction of gas, liquid and solid. To monitor the process and to improve the product quality, as well as to visualize the fault type clearly, a fault diagnosis method based on selforganizing map(SOM) and high dimensional feature extraction method, local tangent space alignment(LTSA),is proposed. In this method, LTSA can reduce the dimension and keep the topology information simultaneously,and SOM distinguishes various states on the output map. Monitoring results of PX oxidation reaction process indicate that the LTSA–SOM can well detect and visualize the fault type.展开更多
Vapor-liquid equilibrium composition and temperature were measured for binary andternary mixtures of benzene,toluene and p-xylene at 101.33 kPa The equilibrium cell of Boubliketal.was modified for the present study.Th...Vapor-liquid equilibrium composition and temperature were measured for binary andternary mixtures of benzene,toluene and p-xylene at 101.33 kPa The equilibrium cell of Boubliketal.was modified for the present study.The experimental vapor-liquid equilibrium data were corre-lated with the Wilson equation.展开更多
Experimental data on density and viscosity at 303.15K and 323.15K are presented for the binary mixtures of p-xylene with cyclohexane, n-heptane, n-octane, sulfolane, N-methyl-2-pyrrolidone and acetic acid.From these d...Experimental data on density and viscosity at 303.15K and 323.15K are presented for the binary mixtures of p-xylene with cyclohexane, n-heptane, n-octane, sulfolane, N-methyl-2-pyrrolidone and acetic acid.From these data, the excess molar volume and deviations in viscosity have been calculated. The computed quantities have been fitted to the Redlich-Kister Equation to derive coefficients and estimate the standard error values. Results are discussed in terms of intermolecular interactions.展开更多
A new apparatus was designed with a thick-walled glass capillary, electric heater tube with red copper and heat preservation. The thick-walled glass capillary was used for its advantages of resistance to acid corrosio...A new apparatus was designed with a thick-walled glass capillary, electric heater tube with red copper and heat preservation. The thick-walled glass capillary was used for its advantages of resistance to acid corrosion and pressure, and ease of observation. The experimental densities over the entire range of mole fraction for the binary mixture of p-xylene＋acetic acid and o-xylene＋acetic acid were measured using the new apparatus at temperatures ranging from 313.15K to 473.15K and pressure ranging from 0.20 to 2,0 MPa. The density values were used in the determination of excess molar volumes, W. The Redlich-Kister equation was used to fit the excess molar volume values, and the coefficients and estimate ot the standard error values were presented. The experimental resuits prove that the density measurement apparatus is successful.展开更多
The oxidation of p-xylene to terephthalic acid with molecular oxygen in acetic acids modified carbon dioxide over Co/Mn/Br catalyst was studied in a batch reactor. The results showed that the oxidation of p-xylene to ...The oxidation of p-xylene to terephthalic acid with molecular oxygen in acetic acids modified carbon dioxide over Co/Mn/Br catalyst was studied in a batch reactor. The results showed that the oxidation of p-xylene to terephthalic acid was severely inhibited when carbon dioxide exceeded a certain amount, the conversion of p-xylene decreased rapidly from 100.0% to 3.3% and the yield of terephthalic acid dropped from 42.6% to trace. Whereas the oxidation processes of p-Tolualdchyde to p-Toluic acid and 4-Carboxybenzaldehyde to tcrcphthalic acid were improved when a relative small amount of CO2 v/as added, Further investigation found that this negative effect may be caused by multiphase reactions emerging.展开更多
The p-xylene(PX) oxidation process is of great industrial importance because of the strong demand of the global polyester fiber.A steady-state model of the PX oxidation has been studied by many researchers.In our prev...The p-xylene(PX) oxidation process is of great industrial importance because of the strong demand of the global polyester fiber.A steady-state model of the PX oxidation has been studied by many researchers.In our previous work,a novel industrial p-xylene oxidation reactor model using the free radical mechanism based kinetics has been developed.However,the disturbances such as production rate change,feed composition variability and reactor temperature changes widely exist in the industry process.In this paper,dynamic simulation of the PX oxidation reactor was designed by Aspen Dynamics and used to develop an effective plantwide control structure,which was capable of effectively handling the disturbances in the load and the temperature of the reactor.Step responses of the control structure to the disturbances were shown and served as the foundation of the smooth operation and advanced control strategy of this process in our future work.展开更多
A combination of photochlorination ofp-xylene and succedent Friedel-Crafts alkylation polymerization was firstly used in the preparation of the hypercrosslinked adsorptive resin. The data of GC-MS and GC showed that a...A combination of photochlorination ofp-xylene and succedent Friedel-Crafts alkylation polymerization was firstly used in the preparation of the hypercrosslinked adsorptive resin. The data of GC-MS and GC showed that a series of chlorizates were produced when p-xylene was photochlorinated. Hypercrosslinked resins could be synthesized by copolymerization, self-polymerization of chlorizates or post crosslinking reaction. The chemical structure and micromorphology of the porous resins were characterized by BET, FF-IR, SEM and elementary analysis （EA）. The results showed that the novel adsorptive resins possess high BET surface near to 1038 m^2/g and large pore volumes range from 0.5 to 1.2 cm^3/g.展开更多
P-xylene(p-C_(8)H_(10))is extremely harmful and dangerous to human health due to high toxicity and strong carcinogenicity.Exploring sensitive material to effectively detect p-xylene is of importance.In this paper,pero...P-xylene(p-C_(8)H_(10))is extremely harmful and dangerous to human health due to high toxicity and strong carcinogenicity.Exploring sensitive material to effectively detect p-xylene is of importance.In this paper,perovskite single crystal(C_(4)H_(9)NH_(3))_(2)PbI_(4) has been successfully synthesized via solution method.The obtained product was analyzed by single crystal X-ray diffraction.With the space group Pbca,orthorhombic(C_(4)H_(9)NH_(3))_(2)PbI_(4) layered perovskite structure consists of an extended two-dimensional network of corner-sharing PbI_(6) octahedron.Single layer perovskite sheets of distorted PbI_(6) octahedron alternated with protonated n-butylammonium cation bilayers,which offers many advantages and provides the possibility of forming a gas sensor device based on the change of resistances.Density functional theory(DFT)simulations regarding the adsorption energy revealed that this organicinorganic hybrid perovskite compound has excellent selectivity toward p-xylene compared with other gases including C_(2)H_(5)OH,C_(6)H_(6),CH_(2)Cl_(2),HCHO,CH_(3)COCH_(3) and C_(7)H_(8).The calculation of electron density,density of states and electron density difference showed the sensing mechanism of p-C_(8)H_(10) is mainly derived from physical adsorption-desorption in view of electron transfer.展开更多
The process of p-xylene liquid phase oxidation to produce purified terephthalic acid(PTA)involves a series of liquid phase radical reactions,chemical absorption,reac-tive crystallization,and evaporation.A commercial P...The process of p-xylene liquid phase oxidation to produce purified terephthalic acid(PTA)involves a series of liquid phase radical reactions,chemical absorption,reac-tive crystallization,and evaporation.A commercial PTA production flow sheet includes a number of unit operations,which construct a complex process system.In this paper,a review of research and development(R&D)works on PTA process carried out in Zhejiang University during recent years is introduced.The works cover the oxidation and crystallization kinetics,gas-liquid mass transfer and evaporation,reactor modeling,database development,novel reactor design,process modeling,simulation,and optimi-zation.The author emphasizes the viewpoint through this case study that chemical reaction engineering should be developed to process system engineering to extend its scope,and particular attention should be paid on reactor and process modeling.展开更多
An attempt has been made to prepare terephthalic acid（TPA） by solvent-free oxidation of p-xylene（PX） with air over tetra（pchlorophenylporphinato） manganese chloride（T（p-Cl）PPMnCl） and cobalt acetate.The co-c...An attempt has been made to prepare terephthalic acid（TPA） by solvent-free oxidation of p-xylene（PX） with air over tetra（pchlorophenylporphinato） manganese chloride（T（p-Cl）PPMnCl） and cobalt acetate.The co-catalysis between T（p-Cl）PPMnCl and Co（OAc）_2 has been discovered under solvent-free conditions.TPA yield could be increased significantly when T（p-Cl）PPMnCl and Co（OAc）_2 were used together.The addition of T（p-Cl）PPMnCl into the reaction mixture over Co（OAc）_2 significantly accelerated the rate-determining step of the oxidation process of PX to TPA.The effect of temperature on reaction was also investigated.展开更多
基金Supported by the Major State Basic Research Development Program of China （2012CB720500）, the National Natural Science Foundation of China （U1162202, 61174118） and the Shanghai Leading Academic Discipline Project （B504）.
文摘The vapor-liquid equilibrium data of four binary systems (acetic acid +p-xylene, methyl acetate +n-propyl acetate, n-propyl acetate +p-xylene and methyl acetate +p-xylene) are measured at 101.33 kPa with Ellis equilibrium still, and then both the NRTL and UNIQUAC models are used in combination with the HOC model for correlating and estimating the vapor-liquid equilibrium of these four binary systems. The estimated binary VLE results using correlated parameters agree well with the measured data except the methyl acetate +p-xylene system which easily causes bumping and liquid rushing out of the sampling tap due to their dramatically different boiling points. The correlation results by NRTL and UNIQUAC models have little difference on the average absolute deviations of temperature and composition of vapor phase, and the results by NRTL model are slightly better than those by UNIQUAC model except for the methyl acetate +n-propyl acetate system, for which the latter gives more accurate correlations.
文摘The alkylation of toluene with methanol to selective formation of p-xylene has been systematically studied. ZSM-12 （MTW）/ZSM-5 co-crystalline zeolite in 40：60 proportions have been synthesized by the same molar gel composition, but at different temperatures and periods than that of ZSM-12 and ZSM-5, separately. All the prepared samples are characterized by XRD, SEM, BET, and XRF. The activity of toluene alkylation was investigated with a mixture of toluene and methanol as a feed over the ZSM-12, ZSM-12/ZSM-5 co-crystalline, ZSM-5, and physical mixture of ZSM-12/ZSM-5. From characterization, it is observed that the ZSM-12/ZSM-5 co-crystalline material is different from that of ZSM-12, ZSM-5, and their physical mixture. Further, the ZSM-12/ZSM-5 co-crystalline zeolite produces the highest content of xylene and has better selectivity for p-xylene than ZSM-12, ZSM-5, and their physical mixture.
文摘The alkylation of toluene with methanol for the selective formation of p-xylene was systematically studied. Very few studies have been reported on the use of superacids such as heteropolyacids on cheap supports, such as clay. This article deals with the use of different heteropoly acids （HPAs）, viz, Dodeca-Tungstophosphoric acid [H3PO4.12WO3.xH2O] （TPA）, Dodeca-Molyhdo phosphoric acid ammonium salt hydrate [H12Mo12N3O40P＋aq] （DMAA）, Dodeca-Molyhdo Phosphoric acid （PMA） on clay （MontmoriUonite, K-10） and as such plain clay. This comparative study reveals that 20%PMA/Clay shows 62% toluene conversion and 100% selectivity toward p-xylene.
基金supported by the Natural Science Foundation of Zhejiang Province of China(No.LQ16D060004)Key Research and Development Projects of Zhejiang Province of China(No.2018C02043)+1 种基金Demonstration Project of Marine Economic Innovation and Development of Zhoushan City of ChinaDemonstration Project of Marine Economic Innovation and Development of Yantai City of China(No.YHCX-SW-L-201705).
文摘The global consumption of p-xylene(PX)for the production of polymers has raised serious concerns about its impact on the environment.As various reports have shown the risks that PX could pose to human health,research into cost-effective remedial methods to remove PX from the environment has gained attraction.In this work,a hierarchical porous crab shell biochar(KCS)was synthesized,characterized,and evaluated for its efficiency to remove PX from aqueous solution.The characterizations of KCS,including the porous structure,surface functional group,phase structure,and surface morphology,were discussed by N_(2) adsorption-desorption,FTIR,XRD,and SEM.Batch adsorption experiments showed that the maximum adsorption capacity of PX on KCS was 393 mg/g within 5 min,larger than most biological/biomass materials,mainly due to the higher specific surface area of 2046 m^(2)/g,and abundant lipophilic functional groups.Subsequent adsorption kinetics study indicated a pseudo-second-order model which implied that the adsorption of PX was due to chemisorption.Thermodynamic parameters showed that the values ofΔH°andΔG°were both negative,indicating that the PX adsorption process on KCS was spontaneous and exothermic.The performance of KCS in delivering a cost-effective,fast,and efficient solution for the removal of PX from aqueous solution would greatly benefit current environmental remediation efforts.
基金Supported by the Natural National Science Foundation of China （20080672） and the Research Fund for the Doctoral Program of Higher Education of China （200803351111）.
文摘During the liquid-phase oxidation of p-xylene,over-oxidation of reactant,intermediates and solvent to carbon dioxide and carbon monoxide is generally known as the burning side reaction.Batch and semi-continuous experiments were carried out,and the experimental data of the burning side reaction were analyzed and reported in this paper.The results showed that the rates of burning side reactions were proportional to the rates of the main reaction,but decreased with the increasing concentrations of reactant and intermediates.The inter-stimulative and competitive relationship between the burning side reaction and the main reaction was confirmed,and the rates of the burning side reaction could be described with some key indexes of the main reaction.According to the mechanism of the side reactions and the kinetics model of main reaction which were proposed and tested in the previous papers,a kinetic model of the burning side reactions involving some key indexes of the main reaction was developed,and the parameters were determined by data fitting of the COx rate curves.The obtained kinetic model could describe the burning side reactions adequately.
基金Supported by China Petrochemical Corporation(X505012)
文摘The viscosities of pure water,the acetic acid+water binary system,and the p-xylene+acetic acid+ water ternary system at different concentrations were determined with a rolling-ball viscometer at temperatures from 313.15 to 473.15 K and pressures from 0.10 to 3.20 MPa.The viscosity data were fitted by a correlation equation for the estimation of the mixture viscosities.The average absolute deviations(AAD)of the correlation for binary and ternary systems are 2.48%and 1.77%,respectively.
基金Supported by the Major State Basic Research Development Program of China (2012CB720500)the National Natural Science Foundation of China (Key Program: U1162202)+1 种基金the National Natural Science Foundation of China (General Program:61174118)Shanghai Leading Academic Discipline Project (B504)
文摘In recent years, immune genetic algorithm (IGA) is gaining popularity for finding the optimal solution for non-linear optimization problems in many engineering applications. However, IGA with deterministic mutation factor suffers from the problem of premature convergence. In this study, a modified self-adaptive immune genetic algorithm (MSIGA) with two memory bases, in which immune concepts are applied to determine the mutation parameters, is proposed to improve the searching ability of the algorithm and maintain population diversity. Performance comparisons with other well-known population-based iterative algorithms show that the proposed method converges quickly to the global optimum and overcomes premature problem. This algorithm is applied to optimize a feed forward neural network to measure the content of products in the combustion side reaction of p-xylene oxidation, and satisfactory results are obtained.
基金supported by the National Key Basic Program of China(2013CB228105)
文摘This work developed a one-step process for renewable p-xylene production by co-catalytic fast pyrolysis (co-CFP) of cellulose and methanol over the different metal oxides modified ZSM5 catalysts. It has been proven that La2O3-modified ZSM5(80) catalyst was an effective one for the production of biobased p-xylene. The selectivity and yield of p-xylene strongly depended on the acidity of the catalysts, reaction temperature, and methanol content. The highest p-xylene yield of 14.5 C-mol% with a p-xylene/xylenes ratio of 86.8% was obtained by the co-CFP of cellulose with 33wt% methanol over 20%La2O3-ZSM5(80) catalyst. The deactivation of the catalysts during the catalytic pyrolysis process was investigated in detail.The reaction pathway for the formation of p-xylene from cellulose was proposed based on the analysis of products and the characterization of catalysts.
基金Supported by the Shanghai Second Polytechnic University Key Discipline Construction-Control Theory & Control Engineering(No.XXKPY1609)the National Natural Science Foundation of China(61422303)+1 种基金Shanghai Talent Development Funding(H200-2R-15111)2017 Shanghai Second Polytechnic University Cultivation Research Program of Young Teachers(02)
文摘The rise in the use of global polyester fiber contributed to strong demand of the Terephthalic acid （TPA）. The liquid-phase catalytic oxidation of p-xylene （PX） to TPA is regarded as a critical and efficient chemical process in industry [ 1 ]. PX oxidation reaction involves many complex side reactions, among which acetic acid combustion and PX combustion are the most important. As the target product of this oxidation process, the quality and yield of TPA are of great concern. However, the improvement of the qualified product yield can bring about the high energy consumption, which means that the economic objectives of this process cannot be achieved simulta- neously because the two objectives are in conflict with each other. In this paper, an improved self-adaptive multi-objective differential evolution algorithm was proposed to handle the multi-objective optimization prob- lems. The immune concept is introduced to the self-adaptive multi-objective differential evolution algorithm （SADE） to strengthen the local search ability and optimization accuracy. The proposed algorithm is successfully tested on several benchmark test problems, and the performance measures such as convergence and divergence metrics are calculated. Subsequently, the multi-objective optimization of an industrial PX oxidation process is carried out using the proposed immune self-adaptive multi-objective differential evolution algorithm （ISADE）. Optimization results indicate that application oflSADE can greatly improve the yield of TPA with low combustion loss without degenerating TA quality.
基金Supported by the Major State Basic Research Development Program of China(2012CB720500)the National Natural Science Foundation of China(6133301021276078)+3 种基金the National Science Fund for Outstanding Young Scholars(61222303)the Fundamental Research Funds for the Central Universities,Shanghai Rising-Star Program(13QH1401200)the Program for New Century Excellent Talents in University(NCET-10-0885)Shanghai R&D Platform Construction Program(13DZ2295300)
文摘Purified terephthalic acid(PTA) is an important chemical raw material. P-xylene(PX) is transformed to terephthalic acid(TA) through oxidation process and TA is refined to produce PTA. The PX oxidation reaction is a complex process involving three-phase reaction of gas, liquid and solid. To monitor the process and to improve the product quality, as well as to visualize the fault type clearly, a fault diagnosis method based on selforganizing map(SOM) and high dimensional feature extraction method, local tangent space alignment(LTSA),is proposed. In this method, LTSA can reduce the dimension and keep the topology information simultaneously,and SOM distinguishes various states on the output map. Monitoring results of PX oxidation reaction process indicate that the LTSA–SOM can well detect and visualize the fault type.
文摘Vapor-liquid equilibrium composition and temperature were measured for binary andternary mixtures of benzene,toluene and p-xylene at 101.33 kPa The equilibrium cell of Boubliketal.was modified for the present study.The experimental vapor-liquid equilibrium data were corre-lated with the Wilson equation.
文摘Experimental data on density and viscosity at 303.15K and 323.15K are presented for the binary mixtures of p-xylene with cyclohexane, n-heptane, n-octane, sulfolane, N-methyl-2-pyrrolidone and acetic acid.From these data, the excess molar volume and deviations in viscosity have been calculated. The computed quantities have been fitted to the Redlich-Kister Equation to derive coefficients and estimate the standard error values. Results are discussed in terms of intermolecular interactions.
基金Supported by China Petrochemical Corporation(X505012)
文摘A new apparatus was designed with a thick-walled glass capillary, electric heater tube with red copper and heat preservation. The thick-walled glass capillary was used for its advantages of resistance to acid corrosion and pressure, and ease of observation. The experimental densities over the entire range of mole fraction for the binary mixture of p-xylene＋acetic acid and o-xylene＋acetic acid were measured using the new apparatus at temperatures ranging from 313.15K to 473.15K and pressure ranging from 0.20 to 2,0 MPa. The density values were used in the determination of excess molar volumes, W. The Redlich-Kister equation was used to fit the excess molar volume values, and the coefficients and estimate ot the standard error values were presented. The experimental resuits prove that the density measurement apparatus is successful.
文摘The oxidation of p-xylene to terephthalic acid with molecular oxygen in acetic acids modified carbon dioxide over Co/Mn/Br catalyst was studied in a batch reactor. The results showed that the oxidation of p-xylene to terephthalic acid was severely inhibited when carbon dioxide exceeded a certain amount, the conversion of p-xylene decreased rapidly from 100.0% to 3.3% and the yield of terephthalic acid dropped from 42.6% to trace. Whereas the oxidation processes of p-Tolualdchyde to p-Toluic acid and 4-Carboxybenzaldehyde to tcrcphthalic acid were improved when a relative small amount of CO2 v/as added, Further investigation found that this negative effect may be caused by multiphase reactions emerging.
基金Supported by the Major State Basic Research Development Program of China(2012CB720500)the National Natural Science Foundation of China(U1162202)+2 种基金the Shanghai Second Polytechnic University Key Discipline Construction(4th term)-Control Theory&Control Engineering(XXKPY1308)the Cultivation Program of Young Teachers in Colleges and Universities of Shanghai(ZZegdl4013)the School Foundation of Shanghai Second Polytechnic University(EGD14XQD02)
文摘The p-xylene(PX) oxidation process is of great industrial importance because of the strong demand of the global polyester fiber.A steady-state model of the PX oxidation has been studied by many researchers.In our previous work,a novel industrial p-xylene oxidation reactor model using the free radical mechanism based kinetics has been developed.However,the disturbances such as production rate change,feed composition variability and reactor temperature changes widely exist in the industry process.In this paper,dynamic simulation of the PX oxidation reactor was designed by Aspen Dynamics and used to develop an effective plantwide control structure,which was capable of effectively handling the disturbances in the load and the temperature of the reactor.Step responses of the control structure to the disturbances were shown and served as the foundation of the smooth operation and advanced control strategy of this process in our future work.
基金support of the National Natural Science Foundation of China(Nos.20574063 and 21004055)
文摘A combination of photochlorination ofp-xylene and succedent Friedel-Crafts alkylation polymerization was firstly used in the preparation of the hypercrosslinked adsorptive resin. The data of GC-MS and GC showed that a series of chlorizates were produced when p-xylene was photochlorinated. Hypercrosslinked resins could be synthesized by copolymerization, self-polymerization of chlorizates or post crosslinking reaction. The chemical structure and micromorphology of the porous resins were characterized by BET, FF-IR, SEM and elementary analysis （EA）. The results showed that the novel adsorptive resins possess high BET surface near to 1038 m^2/g and large pore volumes range from 0.5 to 1.2 cm^3/g.
基金financially supported by the Natural Science Foundation of Hebei(Nos.F2020202027 and F2020202067)the Major National Science and Technology Special Projects(No.2016ZX02301003-004-007)+1 种基金the National Natural Science Foundation of China(No.21271139)the Natural Science Foundation of Tianjin(No.17JCTPJC54500)。
文摘P-xylene(p-C_(8)H_(10))is extremely harmful and dangerous to human health due to high toxicity and strong carcinogenicity.Exploring sensitive material to effectively detect p-xylene is of importance.In this paper,perovskite single crystal(C_(4)H_(9)NH_(3))_(2)PbI_(4) has been successfully synthesized via solution method.The obtained product was analyzed by single crystal X-ray diffraction.With the space group Pbca,orthorhombic(C_(4)H_(9)NH_(3))_(2)PbI_(4) layered perovskite structure consists of an extended two-dimensional network of corner-sharing PbI_(6) octahedron.Single layer perovskite sheets of distorted PbI_(6) octahedron alternated with protonated n-butylammonium cation bilayers,which offers many advantages and provides the possibility of forming a gas sensor device based on the change of resistances.Density functional theory(DFT)simulations regarding the adsorption energy revealed that this organicinorganic hybrid perovskite compound has excellent selectivity toward p-xylene compared with other gases including C_(2)H_(5)OH,C_(6)H_(6),CH_(2)Cl_(2),HCHO,CH_(3)COCH_(3) and C_(7)H_(8).The calculation of electron density,density of states and electron density difference showed the sensing mechanism of p-C_(8)H_(10) is mainly derived from physical adsorption-desorption in view of electron transfer.
基金financial support provided by the National Natural Science Foundation of China(Grant No.20076039)Zhejiang University“211”Foundation for Key Discipline Constructionthe financial support in part provided by SINOPEC,Yizheng Chemical Fiber Co.Ltd,Yangzi Petrochemical Co.Ltd,Shanghai Petrochemical Co.Ltd,Zhejiang Hualian Sunshine Co.Ltd,China Tex Ind Eng Ins.,Honeywell(China)Co.Ltd and BP America Inc.
文摘The process of p-xylene liquid phase oxidation to produce purified terephthalic acid(PTA)involves a series of liquid phase radical reactions,chemical absorption,reac-tive crystallization,and evaporation.A commercial PTA production flow sheet includes a number of unit operations,which construct a complex process system.In this paper,a review of research and development(R&D)works on PTA process carried out in Zhejiang University during recent years is introduced.The works cover the oxidation and crystallization kinetics,gas-liquid mass transfer and evaporation,reactor modeling,database development,novel reactor design,process modeling,simulation,and optimi-zation.The author emphasizes the viewpoint through this case study that chemical reaction engineering should be developed to process system engineering to extend its scope,and particular attention should be paid on reactor and process modeling.
文摘An attempt has been made to prepare terephthalic acid（TPA） by solvent-free oxidation of p-xylene（PX） with air over tetra（pchlorophenylporphinato） manganese chloride（T（p-Cl）PPMnCl） and cobalt acetate.The co-catalysis between T（p-Cl）PPMnCl and Co（OAc）_2 has been discovered under solvent-free conditions.TPA yield could be increased significantly when T（p-Cl）PPMnCl and Co（OAc）_2 were used together.The addition of T（p-Cl）PPMnCl into the reaction mixture over Co（OAc）_2 significantly accelerated the rate-determining step of the oxidation process of PX to TPA.The effect of temperature on reaction was also investigated.
