Liquid-phase esterification of methacrylic acid with methanol catalyzed by cation-exchange resin in a fixed bed reactor:Experimental and kinetic studies

The kinetic behavior of esterification between methacrylic acid and methanol catalyzed by NKC-9 resin was studied in a fixed bed reactor.The reaction was conducted in the temperature range of 323.15 to 368.15 K with the molar ratio of reactants from 0.8 to 1.4 under certain pressure.The measurement data were regression with the pseudo-homogeneous(P-H),Eley-Rideal(E-R),and Langmuir-Hinshelwood(L-H)heterogeneous kinetic models.Independent adsorption experiments were implemented to gain the adsorption equilibrium constants of four components.Among the above three models,the L-H model exhibited the best fitting results.The stability of NKC-9 was evaluated by long-term running with the yield of methyl methacrylate no decrease during 3000 h operation.The structure and physicochemical properties of the new and used catalyst were performed by several characterizations including thermogravimetric analysis(TG),scanning electron microscope(SEM),X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FT-IR)and so on.

Elution Behaviour of Monocarboxylic Acids on a Cation-exchange Resin Column

The retention mechanism of monocarboxylic acids on a cation-exchange resin column was investigated. It was assumed that both Donnan membrane equilibrium and adsorption equilibrium were involved in the chromatographic process. On the basis of the proposed mechanism, an equation was derived for correlating distribution coefficient, Kd, dissociation constant, Aa, and adsorption equilibrium constant, K, of the analyzed acid. By this approach, retention data for some aliphatic acids under different operating conditions were predicted. Results are reasonably in agreement with experiment.

THE EFFECT OF THE ACID CATALYST ON THE PREPARATION OF MQ SILICONE RESINS

MQ silicone resins were prepared through hydrolytic condensation of ethyl polysilicate or tetraethoxysilane and hexamethyl disiloxane. The unit ratio of the MQ resins was determined by Si-29-NMR. The relationship of the unit ratio of the product resins with that in the feed was studied. When the reaction was catalyzed by aqueous hydrochloric acid, and the unit ratio of M to Q in the feed was more than 1, the unit ratio of the product was usually lower than that of the feed. The MQ silicon with an unit ratio of M/Q > 2 could not be obtained. However, if the reaction was catalyzed by concentrated sulfuric acid and the reverse hydrolysis process was employed, MQ silicone resin with very high M/Q ratio was successfully prepared.

Tuning the properties of Ni-based catalyst via La incorporation for efficient hydrogenation of petroleum resin

The hydrogenation of petroleum resin(PR)is an effective process to prepare high value-added hydrogenated PR(HPR).However,the preparation of non-noble metal-based catalysts with high catalytic activity for PR hydrogenation still remains a challenge.Herein,a La promoted Ni-based catalyst is reported through the thermal reduction of quaternary Ni La Mg Al-layered double hydroxides(Ni La Mg Al-LDHs).The incorporation of La is beneficial to the reduction and stability of Ni particles with reduced particle size,and the increased alkalinity effectively mitigates the breakage of molecular chains of PR.As a result,the La promoted Ni-based catalyst exhibits high catalytic activity and excellent stability for PR hydrogenation.A hydrogenation degree of 95.4%and 96.1%can be achieved for HC_(5)PR and HC_(9) PR with less reduced softening point,respectively.Notably,the hydrogenation degree still maintains at 92.7%even after 100 hours’reaction,much better than that without La incorporation or prepared using conventional impregnation method.

Preparation of Low Cost Activated Carbon from Deactivated Resin Catalyst for Methyl Tert-Butyl Ether Synthesis and Its Application in Dimethyl Sulfide Adsorption with Transition Metal Impregnation

In this paper, a low-cost activated carbon(AC) was prepared from deactivated resin catalyst(DRC) for methyl tert-butyl ether(MTBE) synthesis through carbonization and subsequent steam activation treatment. The activated carbon was characterized in detail. After loading various transition metals, including Cu^(2+), Ag+, Co^(2+), Ni^(2+), Zn^(2+), and Fe^(3+) via the ultrasonic-assisted impregnation method, a series of metal-loaded adsorbents(xM-AC) were obtained and their dimethyl sulfide(DMS) adsorption performance was investigated in a batch system. Among these adsorbents, 15Cu-AC presented a superior DMS adsorption capacity equating to 58.986 mg/g due to the formation of S-M(σ) bonds between Cu^(2+) and sulfur atoms of DMS as confirmed by the Raman spectra and kinetic study.

Optimizing the Synthesis of Ethyl tert-Butyl Ether in Continuous Catalytic Distillation Column Using New Ion Exchange Resin Catalyst

Liquid phase synthesis of one of the important fuel oxygenate, ethyl tert-butyl ether （ETBE）, from etha-nol and tert-butyl alcohol （TBA） has been studied in catalytic distillation column （CDC） using ion exchange resin catalyst CT-145H. A packed CDC of 1.2 m height and 50 mm diameter with indigenously developed reactive sec-tion packing was used to generate experimental data. Effect of different key variables on product purity in distillate, was investigated to find the optimum operating conditions for ETBE synthesis. The optimum conditions for 0.2 kg·s-1 of ethanol feed were found：reboiler duty of 375 W, molar feed ratio of 1︰1.3 of reactants, and reflux ratio of 7. Concentration profiles for each component along each column section at optimum conditions were also drawn. Neither output nor input multiplicity was observed at experimental conditions.

Study on the Stability of Ion-exchange Resin Catalysts:Ⅰ. TGA as a Rapid Evaluating Method

The thermal stability of five commercial ion-exchange resin catalysts was studied by means of thermal gravimetric analysis （TGA） at elevated temperatures of up to 600℃ and isothermal temperatures in the range of 150℃ and 200 ℃. Resin samples with different initial water contents were also investigated. The study indicated that TGA, as a complementary evaluating method for the plug flow reactor system approach, could be used as a fast analyzing means for study on the thermal stability of ion-exchange resin catalysts. The stoichiometric calculation of the isothermally treated resin catalysts based on the FTIR analysis and acid capacity confirmed that the weight loss of the resins at 150℃ and 200℃ was caused by the desulfonation process and that desulfonation occurred mainly at the para-position of the benzene ring in the resins. H＋ ions and moisture played an important role in the desulfonation process.

Study on Stability of Ion-exchange Resin Catalysts:Ⅱ. Desulfonation during Isobutylene Dimerization

The performance of ion-exchange resin catalysts during isobutene (IB) dimerization was investigated under different IB contents,temperatures and liquid-volume hourly space velocity (LHSV) using a plug flow reactor in the absence of any selectivity enhancing component.High IB content and temperature resulted in a high conversion and C12 selectivity bu low C8 selectivity.The influence of LHSV was related with the IB content:LHSV had great effect at high IB content,while the performance of ion-exchange resin changed little with LHSV if IB content was low.The effect of water on the stability of resins was also studied.Desulfonation was observed during the C4 dimerization reaction when water was added to the feed.Chlorinated resin was more stable than conventional polystyrene-based resins during the test.

Preparation and Characterization of Macroporous Resin Immobilized Pd－Cu Bimetallic Cluster Catalysts

The Solvated Metal Atom Impregnation (SMAI) technique was employed to prepare macroporous resin immobilized Pd--Cu bimetallic cluster catalysts. The X--ray diffraction (XRD) and transmission electron micrograph (TEM) showed that Pd--Cu alloy was formed and the particle sizes of Pd--Cu clusters were very small, with average diameters <3nm. X--ray photoelectron spectroscopy indicated that both Pd and Cu were in zero--valent state. The catalytic activities of the macroporous resin immobilized Pd--Cu catalysts in hydrogenation of 4--methyl--3--penten--2--one were much greater than that of the carbon supported Pd--Cu catalysts.

Investigating the Effect of Catalyst Type and Concentration on the functional Group Conversion in Castor Seed Oil Alkyd Resin Production

Significant scientific and economic benefits may be derived from investigating the best choice of catalyst in the alkyd resin synthesis. The effect of catalyst type and concentration on the production of alkyd resin using castor seed oil (CSO) was evaluated. Lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide were investigated. The fatty acid profile of the raw CSO was determined using GC-MS while structural elucidation of the CSO based alkyd resins was determined using FTIR spectrometry. The CSO modified alkyd resin produced has acid values of 5.0, 5.61, 7.0 8.24 and 11 for lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide respectively. The extent of reaction was 95%, 95%, 91%, 89% and 88% for lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide respectively at the reaction time of 150 minutes. The alcoholysis reaction completion time was fastest in LiOH followed by PbO, CaCO3, NaOH and CaO catalyst. Physico-chemical parameters of the oil and performance evaluation of the alkyd films suggest that they are sustainable materials for surface coating. LiOH shows excellent robustness to expanded process parameters.

Kinetics and Mechanism of Hydration of Acrylic Acid over Ion-exchanged Resin:Experimental Exploration and DFT Calculation

Liquid-phase acrylic acid hydration over solid-phase catalysts is a key reaction for the industrial productionof 3-hydroxypropionic acid. However, the relevant literature primarily focuses on the experimental aspects of catalystscreening and exploring reaction conditions, with few accurate descriptions of the reaction kinetics and determination ofthe reaction mechanism. Here, we combined kinetics experiments and theoretical calculations to elucidate the kinetics andmechanism of acrylic acid hydration on a resin catalyst. The pseudo-homogeneous model, and Langmuir-Hinshelwood-Haugen-Watson and Elie-Riedel (ER) heterogeneous models were used to explain the experimental kinetics data. TheER model can explain the experimental data very well, suggesting strong adsorption of acrylic acid on the surface of theresin catalyst. Furthermore, density functional theory calculations show that the hydration follows a stepwise, rather than aconcerted, reaction pathway. The present study provides theoretical insights into the reaction mechanism and kinetics, fillingthe gap in our understanding of the reaction on a fundamental level.

EFFECT OF CATALYST ON THE REACTION BETWEEN ACTIVE ESTER AND EPOXY RESIN

In this study the third amine and phosphine were selected as the catalysts of epoxy resin, the influence of these catalysts on curing reaction was observed in comparison with the former selected quadrupole onium salt and the influence of them on physical properties of solidified matter was also studied. (Author abstract) 10 Refs.

Selective hydrogenation of phenol to cyclohexanone in water over Pd catalysts supported on Amberlyst-45

A series of Pd catalysts were prepared on different supports（Fe2O3,SiO2,ZnO,MgO,Al2O3,carbon,and Amberlyst-45） and used in the selective hydrogenation of phenol to cyclohexanone in water.The Amberlyst-45 supported Pd catalyst（Pd/A-45） was highly active and selective under mild conditions（40-100 ℃,0.2-1 MPa）,giving a selectivity of cyclohexanone higher than 89%even at complete conversion of phenol.Experiments with different Pd loadings（or different particle sizes） confirmed that the formation of cyclohexanone was a structure sensitive reaction,and Pd particles of12-14 nm on Amberlyst-45 gave better selectivity and stability.

Change of asphaltene and resin properties after catalytic aquathermolysis

Resin and asphaltene were separated from Liaohe heavy oil. Catalytic aquathermolysis of asphaltene and resin was investigated by using water soluble catalysts （NiSO4 and FeSO4） and oil soluble catalysts （nickel naphthenate and iron naphthenate）. Before and after aquathermolysis, the properties of the resin and asphaltene was compared by means of ultimate analysis, vapor pressure osmometer （VPO） average molecular weight, X-ray diffraction （XRD）,^13C and ^1H nuclear magnetic resonance （NMR）. The conversion sequence was as follows： No-catalyst〈NiSO4〈FeSO4〈nickel naphthenate〈iron naphthenate. In the presence of catalysts, the amount of H2 and CO increased significantly, while H2S in the gas product decreased. The molecular weight of asphaltene and resin increased after reaction without catalyst. But the catalysts restrained this trend. The H/C ratio of asphaltene and resin decreased after reaction. From the results of average structural parameters and molecular weight, it was found that asphaltene and resin were partly aggregated after aquathermolysis.

D301 resin as a solid base for phosphine-free Heck reactions with heteroaryl halides

A new and practical method of the D301 resin,a weak basic anion exchange resin with secondary amine functionality（Grade Matrix Structure：Styrene-DVB D301R）,used as base to Heck reactions catalyzed by palladium reagent without phosphine compound as ligand is described.It was found that the D301 resin used as base is an efficient and reusable base and can be regenerated and recycled in the reaction.The olefmation of heteroaryl halides prepared the corresponding products in good yields using D301 resin as base.

Fe,N,S-doped porous carbon as oxygen reduction reaction catalyst in acidic medium with high activity and durability synthesized using CaCl_2 as template

Proton exchange membrane fuel cells suffer from the sluggish kinetics of the oxygen reduction reaction(ORR)and the high cost of Pt catalysts.In the present work,a high‐performance ORR catalystbased on Fe,N,S‐doped porous carbon(FeNS‐PC)was synthesized using melamine formaldehyderesin as C and N precursors,Fe(SCN)3as Fe and S precursors,and CaCl2as a template via a two‐stepheat treatment without a harsh template removal step.The results show that the catalyst treated at900℃(FeNS‐PC‐900)had a high surface area of775m2/g,a high mass activity of10.2A/g in anacidic medium,and excellent durability;the half‐wave potential decreased by only20mV after10000potential cycles.The FeNS‐PC‐900catalyst was used as the cathode in a proton exchangemembrane fuel cell and delivered a peak power density of0.49W/cm2.FeNS‐PC‐900therefore hasgood potential for use in practical applications.

Factor Affecting Gel Time/Process-Ability of Urea Formaldehyde Resin Based Wood Adhesives

Urea-formaldehyde (UF) resin presents the most utilized adhesive system in the manufacture of plywood, particleboard and fiberboard. At the temperatures above 100°C in the presence of hardener, this resin undergoes cross-linking reaction and the formation of three dimensional cross linked structures takes place and bonding of wood particles in a hot press [1]. UF powder resins show high reactivity and good performance in the production and by their low price;however they lack in water resistance of the hardened resin [2]. Urea-formaldehyde (UF) resins are the most important type of adhesive resins for the production of wood based panels but process-ability and curing behavior of urea formaldehyde resin depended on various factors related to resin properties, types of wood and their properties, amount & type of catalyst, types and amount of polymers addition and environmental conditions [3]. This factor decides the process-ability of UF resin based composite during manufacturing of plywood, particle board and fiberboard. In this review paper, various factors affecting gel time and process-ability of UF resin based wood composite are reviewed.

Immobilized Ruthenium Catalyst for Carbon Dioxide Hydrogenation

Three kinds of cross linked polystyrene resin （PS） supported ruthenium complexes were developed as catalysts for the synthesis of formic acid from carbon dioxide hydrogenation. Many factors, such as the functionalized supports, solvents and ligands, could influence their activities and reuse performances greatly. These immobilized catalysts also offer the industrial advantages such as easy separation.

一种耐酸耐碱高强树脂的合成及性能

小套管二次固井是一种新型的固井工艺,针对目前由于水泥自身脆性大易气窜和水窜且为碱性固化体、易受压产生裂缝、易受酸性介质破坏的问题,以D-33二元醇和顺丁烯二酸为原料,苯乙烯作为活性稀释剂合成了一种不饱和型聚酯树脂。在树脂体系中引入填料,提高产品韧性及抗压强度。采用傅里叶变换红外光谱仪对树脂进行表征;通过万能试验机对树脂体系进行性能评价。结果表明,目标产物包含羰基、碳碳双键和苯环对位取代结构的特征峰,固化体系为过氧化二苯甲酰/N,N-二甲基苯胺,其在50℃、60℃和70℃条件下的添加量分别为0.2%/0.02%、0.1%/0.02%、0.1%/0.01%,万能试验机测试结果显示,在50℃、60℃和70℃下养护24h后的抗压强度分别约为50MPa、70MPa、90MPa。实验获得了一种聚合时间可调、黏度小、抗压强度高且耐酸耐碱的固井材料,有望在水平井重复压裂改造中大规模使用。

邻苯二甲腈树脂催化聚合机理及其性能的研究进展

邻苯二甲腈树脂具有优异的力学性能、耐高温、阻燃等特性,广泛应用于航空航天、石油化工、电子封装等领域。但传统的邻苯二甲腈单体存在固化温度高、加工窗口窄、固化速度慢等缺点,严重限制了其应用。催化剂可以弥补以上不足,但不同催化剂的催化作用机理及所生成的邻苯二甲腈树脂性能均有所不同。文中主要综述了氨基、亚胺基、羟基/巯基、自由基等催化邻苯二甲腈单体的聚合机理以及邻苯二甲腈树脂性能的研究,分析了邻苯二甲腈树脂结构对其性能的影响,进一步展望了其发展趋势。