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Effect of interface kinetics on the eutectic growth

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Science China(Technological Sciences) 2005年第4期48卷 361-371页

作者： LI Jinfu ZHOU Yaohe State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030China State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030China

The atom-attachment kinetics at the solid-liquid interface was incorporated into the eutectic growth theory. The dependence of kinetic undercooling on the structure of the eutectic phases was investigated. Due to the introduction of the kinetic effect, the coupled eutectic growth can proceed in a wider undercooling range, but the growth velocity decreases while the minimum eutectic lamellar spacing remains unchanged. The proportion of kinetic undercooling to the total undercooling is dependent not only on the growth velocity, but also on the phase diagram. Calculation indicated that the proportion decreases as the crystallization temperature range of single eutectic phase at the eutectic composition enlarges.

关键词： eutectic solidification, crystal growth kinetics, phase diagram structure.

kinetics of hydrate formation using gas bubble suspended in water

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Science China Chemistry 2002年第2期45卷 208-215页

作者：马昌峰陈光进郭天民 High Pressure Fluid Phase Behavior & Property Research Laboratory School of Chemical Engineering University of Petroleum Beijing China

An innovative experimental technique, which was devised to study the effects of temperature and pressure on the rate of hydrate formation at the surface of a gas bubble suspended in a stagnant water phase, was adapted in this work. Under such conditions, the hydrate-growth process is free from dynamic mass transfer factors. The rate of hydrate formation of methane and carbon dioxide has been systematically studied. The measured hydrate-growth data were correlated by using the molar Gibbs free energy as driving force. In the course of the experiments, some interesting surface phenomena were observed.

关键词： hydrate formation, kinetics, suspended gas bubble, methane, carbon dioxide.

kinetics and reaction mechanism of phenol hydroxylation catalyzed by La-Cu_4FeAlCO_3

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Science China Chemistry 2005年第6期48卷 530-537页

作者： CHEN Chunxia1,2, XU Chenghua1, FENG Liangrong1, SUO Jishuan1 & QIU Fali1 1. Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China 2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu 610041 China

The present work synthesizes La-Cu4FeAlCO3 catalyst under microwave irradiation and characterizes its structure using XRD and IR techniques. The results show that the obtained La-Cu4FeAlCO3 has a hydrotalcite structure. In the phenol hydroxylation with H2O2 catalyzed by La-Cu4FeAlCO3, the effects of reaction time and phenol/H2O2 molar ratio on the phenol hy-droxylation, and relationships between the initial hydroxylation rate with concentration of the catalyst, phenol, H2O2 and reaction temperature are also investigated in details. It is shown the phenol conversion can reach 50.09% (mol percent) in the phenol hydroxylation catalyzed by La-Cu4FeAlCO3, under the reaction conditions of the molar ratio of phenol/H2O2 1/2, the amount ratio of phenol/catalyst 20, reaction temperature 343 K, reaction time 120 min, 10 mL distilled water as solvent. Moreover, a kinetic equation of v = k[La ? Cu 4 FeAlCO 3 ][C 6 H 5 OH][H 2 O 2]. and the activation energy of Ea=58.37 kJ/mol are obtained according to the kinetic studies. Due to the fact that the HO-Cu+-OH species are detected in La-Cu4FeAlCO3/H2O2 system by XPS, the new mechanism about the generation of hydroxyl free radicals in the phenol hydroxylation is pro-posed, which is supposed that HO-Cu+-OH species are transition state in this reaction.

关键词： rare earth, hydrotalcite, microwave irradiation, phenol hydroxylation, kinetics, reaction mechanism.

Study on Zn_2SiO_4 Formation kinetics and Activity Stability of Desulfurization Sorbent

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China Petroleum Processing & Petrochemical Technology 2015年第1期17卷 6-15页

作者： Zou Kang Lin Wei Tian Huiping Xu Guangtong Wang Lei Xu Hua SINOPEC Research Institute of Petroleum Processing

A new industrial S Zorb sorbent(Ni/Zn O-P) was prepared by using the spray drying technique. The other two traditional sorbents(Ni/Zn O-M and Ni/Zn O-H) were prepared in exactly the same way except the use of different silica-alumina binder matrices. The XRD, Rietveld quantitative phase analysis, BET, and laser particle size analysis were employed to characterize their physico-chemical properties. The deactivation mechanism and desulfurization kinetics of sorbent was investigated on a water vapor aging treatment device. It was shown that both the water vapor pressure and reaction temperature significantly could influence the formation rate of inactive Zn2 Si O4, which could decrease the sulfur storage capacity of sorbents. The Zn2 Si O4 content profiles could be fitted into the zero order equation, from which the apparent rate constant k and the activation energy E a were calculated. The matrix P greatly raised the E a of Zn2 Si O4 formation due to the less bridged hydroxyl silanol groups on its surface, which accounted for the high stability of Ni/Zn O-P. The desulfurization performance of the fresh and aged sorbents showed that the overall average sulfur conversion of Ni/Zn O-P(aged) was 92%, which was close to that of fresh sorbents(95%), and was higher than that of Ni/Zn O-M(aged)(86%) and Ni/Zn O-H(aged)(90%). Based on these findings, the application of Ni/Zn O-P can greatly improve the long-term running stability of the industrial unit.

关键词： kinetics, Zn2SiO4, desulfurization activity, sorbent, high stability

Non-isothermal Crystallization kinetics of Modified Poly(ethylene terephthalate) with Ultraviolet Protection

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Journal of Donghua University(English Edition) 2002年第1期19卷 56-59页

作者：滕翠青 Dong Hua Univ. Shanghai 200051 China

The non-isothermal crystallization kinetics of modified poly(ethylene terephthalate) (PET) with the function of ultraviolet (UV) protection was studied by means of differential scanning calorimetry. The kinetics of the modified polymer under non-isothermal crystallization was analyzed by Ozawa equation. The crystallization behavior of the modified polymer obeyed Ozawa theory. The additives in the polymer whose function was UV-resistant acted as crystal nucleus in the processing of crystallization, which resulted in the increase of Avrami index and the crystallization rate of the cooling system.

关键词： poly(ethylene terephthalate), non-isothermal crystallization, kinetics, ultraviolet-resistant fibers.

Research of kinetics of Electroless Ni-Cu-P Alloy Plating on Polyester Fabric

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Journal of Donghua University(English Edition) 2002年第2期19卷 41-43页

作者：陈震兵陈小立 College of Chemistry and Chemical Engineering Dong Hua University Shanghai 200051

All the variables that may affect the Ni-Cu-P alloy deposition rate on polyester fabric were studied , and the activation energy and the reaction orders were determined. The deposition rate equation was also derived.

关键词： electroless plating, Ni-Cu-P alloy, reaction kinetics, PET fabric

The two steps thermal decomposition of titanium hydride and two steps foaming of Al alloy

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Science China Chemistry 2005年第6期48卷 523-529页

作者： SHANG Jintang HE Deping South-east University Nanjing 210096 China South-east University Nanjing 210096 China

Two steps foaming (TSF) technique was proposed to prepare shaped Al alloy foam. Based on the thermal decomposition kinetics equation of titanium hydride, the relationship be-tween two steps thermal decomposition kinetics of titanium hydride and two steps foaming Al alloy melt was studied. Two steps thermal decomposition curve of titanium hydride under in-creasing and constant temperature was calculated respectively. The hydrogen mass needed in the second foaming step was also calculated. Results showed that the hydrogen mass of the second thermal decomposition of titanium hydride is enough for the second foaming step in the condition of as-received Al melt foaming. Experimental and theoretical results indicate that two steps foaming technique can be used to prepare Al alloy foam with high porosity, shaped com-ponents and sandwich with Al alloy foam core.

关键词： two steps foaming, titanium hydride, thermal decomposition kinetics, Al alloy foam, shaped components.

Study on Alternating Copolymerization of Polyester-amides

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Journal of Donghua University(English Edition) 2002年第4期19卷 87-91页

作者：魏文良李建梅朱方亮 College of Material Science and Technology Dong Hua UniversityShanghai 200051

The preparing methods, choice of catalysts and reaction kinetics of one of the monomers, diesteramide(DEA), of polyester-amides were investigated in details. The chemical structure of DEA was analyzed. And the Polyester-amides (PEA) were obtained by melt copolymerization with DEA. It is shown that DEA can be synthesized by DMT and hexamethylene diamine with the catalyst EX - 1 or EX - 2. The relationship between reaction rate of synthesizing monomer and concentration of hexamethylene diamine is first order kinetic relation.

关键词： polyester-amides, reaction kinetics, alternating copolymerization, structure

Kinetic study of the hydrocarbon generation from Upper Paleozoic coals in Ordos Basin

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Science China Earth Sciences 2003年第4期46卷 333-341页

作者：付少英彭平安张文正刘金钟李剑峰昝川莉 State Key Laboratory of Organic Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sci-ences Guangzhou Marine Geological Survey Ministry of Land and Resources Guangzhou 510760 China Analysis Center Research Institute of Exploration and Development Changqing Petroleum Oilfield

Kinetic parameters were characterized for the formation of the C1—C5 hydrocarbons generating from Taiyuan and Shanxi coal in the Upper Paleozoic of the Ordos Basin, through pres-surized simulation experiment designed for the kinetic study of hydrocarbon generation. Based on the palaeogeothermal evolution of the Upper Paleozoic strata in the Ordos Basin, the formation and evolution of gas from Taiyuan and Shanxi coal in the eastern and central regions of the Ordos Basin were reproduced, and it is suggested that large scale secondary hydrocarbon generation does not exist during the uplifting and cooling process of the basin at the end of Early Cretaceous. Some of the factors affecting the behavior of the coal-generated gas were also discussed, and it is emphasized that the most fundamental element determining the hydrocarbon generation behavior is the characteristic of the precursor hydrocarbon-source rock.

关键词： Ordos Basin, Taiyuan coal, Shanxi coal, hydrocarbon generation kinetics, simulation experiment.