Preparation and properties of urethane alkyd based on a castor oil/jatropha oil mixture

Castor oil is the only major natural vegetable oil that contains a hydroxyl group and so it is widely used in many chemical industries, especially in the production of polyurethanes. In this work, castor oil was interesterified with jatropha oil and the product was subsequently reacted with toluene diisocyanate to obtain urethane alkyd. The prepared urethane alkyd was characterized and its properties were determined and compared with those of the conventional (glycerol/jatropha oil) and commercial urethane alkyds. The castor oil/jatropha oil-based urethane alkyd had a lower molecular weight and viscosity, a slightly lower hardness and greatly longer drying time than the conventional and commercial urethane alkyds, but otherwise the film properties were broadly similar, including being very flexible, with an excellent adhesion and high impact resistance. In addition, they also exhibited excellent resistance to water and acid.     

Trigeneration running with raw jatropha oil

The performance and the efficiency of a trigeneration system fueling with pure diesel and with raw jatropha oil are investigated using the ECLIPSE software. The study is based on a diesel engine generating set. The genset is used for electrical power generation only, acting as a single generation. The trigeneration system consists of the genset, a waste heat recovery system and an absorption refrigerator. The genset is used to generate electricity; the waste heat system is used to collect the waste heat from the cooling system and the exhaust from the engine, to supply heating/hot water; and the absorption refrigerator is used to supply cooling/refrigeration, which is driven by the waste heat from the engine instead of electricity. A comparison of the thermal efficiencies and the CO₂ emissions of trigeneration with single generation and cogeneration (combined heat and power — CHP) is carried out. The results from the study show that the thermal efficiency of trigeneration is higher than that of single generation; the CO₂ emissions of trigeneration are lower than that of single generation. The results also show the performance differences between the trigeneration and single generation; and the differences between trigeneration and cogeneration.     

Combustion characteristics of jatropha oil droplet at various oil temperatures

Jatropha oil which is a large, branched triglycerides type vegetable oil has good potential as an alternative diesel fuel. Its combustion characteristics have been observed experimentally by igniting the oil droplet of various diameters and temperatures on a junction of a thermocouple. The combustion characteristics are identified from flame image and temperature signal in the center of the droplet. The results show that the jatropha oil droplet performs two steps combustion. Fatty acid burned in the first step and glycerol does in the second step. The onset of micro-explosion occurs shortly before the second step combustion and it becomes more frequent as the oil temperature is increased.     

Production of hydrogen for fuel cells by steam reforming of ethanol over supported noble metal catalysts

The catalytic performance of supported noble metal catalysts for the steam reforming (SR) of ethanol has been investigated in the temperature range of 600–850 °C with respect to the nature of the active metallic phase (Rh, Ru, Pt, Pd), the nature of the support (Al₂O₃, MgO, TiO₂) and the metal loading (0–5 wt.%). It is found that for low-loaded catalysts, Rh is significantly more active and selective toward hydrogen formation compared to Ru, Pt and Pd, which show a similar behavior. The catalytic performance of Rh and, particularly, Ru is significantly improved with increasing metal loading, leading to higher ethanol conversions and hydrogen selectivities at given reaction temperatures. The catalytic activity and selectivity of high-loaded Ru catalysts is comparable to that of Rh and, therefore, ruthenium was further investigated as a less costly alternative. It was found that, under certain reaction conditions, the 5% Ru/Al₂O₃ catalyst is able to completely convert ethanol with selectivities toward hydrogen above 95%, the only byproduct being methane. Long-term tests conducted under severe conditions showed that the catalyst is acceptably stable and could be a good candidate for the production of hydrogen by steam reforming of ethanol for fuel cell applications.     

Hydrodeoxygenation of guaiacol on noble metal catalysts

Hydrodeoxygenation (HDO) performed at high temperatures and pressures is one alternative for upgrading of pyrolysis oils from biomass. Studies on zirconia-supported mono- and bimetallic noble metal (Rh, Pd, Pt) catalysts showed these catalysts to be active and selective in the hydrogenation of guaiacol (GUA) at 100 °C and in the HDO of GUA at 300 °C. GUA was used as model compound for wood-based pyrolysis oil. At the temperatures tested, the performance of the noble metal catalysts, especially the Rh-containing catalysts was similar or better than that of the conventional sulfided CoMo/Al₂O₃ catalyst. The carbon deposition on the noble metal catalysts was lower than that on the sulfided CoMo/Al₂O₃ catalyst. The performance of the Rh-containing catalysts in the reactions of GUA at the tested conditions demonstrates their potential in the upgrading of wood-based pyrolysis oils.     

小桐子油生物基多元醇的合成及其在硬质聚氨酯泡沫中的应用

通过对小桐子油双键进行环氧化、羟基化反应,成功制备出小桐子油生物基多元醇,并在硬质聚氨酯泡沫中进行了应用。小桐子油较佳环氧化工艺条件为：甲酸用量为理论用量的0．5倍、双氧水用量为理论用量的1．5倍、催化剂质量为小桐子油质量的2％,反应温度60℃,反应时间8h;较佳的羟基化条件为：n（二异丙醇胺）：n（环氧小桐子油）=1．3：1、反应温度155℃、反应时间6h;泡沫应用结果表明：在实现替代石化类聚醚多元醇不超过45份的情况下,制得的硬质聚氨酯泡沫与采用石化类聚醚多元醇制得的泡沫性能相当。     

Oscillatory behaviour during the oxidation of methane over palladium metal catalysts

Oscillatory reactions over palladium foil and wire catalysts during the oxidation of methane have been investigated over a wide range of reaction temperatures and argon/methane/oxygen feed gas compositions. Characterisation of the catalyst has also been carried out using scanning electron microscopy (SEM) techniques, which revealed the presence of a porous surface. This suggested that the metal surface has undergone a change since the reaction commenced, and using X-ray powder diffraction (XRD) techniques the palladium phase was shown to be the dominant phase present. Hysteresis phenomena were observed in the activity of the reaction as the temperature was cycled up and down, showing that the metal surface was continually changing throughout the reaction. The activation energies of the reaction during the high reactivity mode, PdO, and low reactivity mode, Pd, were also calculated. Oscillation rates were observed to depend on the dominant surface. Oscillations were frequent when the high reactivity mode was dominant while the activation energy of this mode was found to be low. When the low reactivity mode was dominant, the oscillations were slower and the activation energy was three times larger. The results obtained imply that the behaviour of the palladium surface, switching back and forth from the reduced state to the oxidised state, is responsible for the oscillatory behaviour seen in this system.     

Catalytic wet oxidation of p-chlorophenol over supported noble metal catalysts

Heterogeneous catalytic wet oxidation of aqueous p-chlorophenol (p-CP) solution was investigated at 453 K and 2.6 MPa in a slurry reactor. The performance of noble metal catalysts was compared with that of traditional manganese catalysts. Activated carbon supported catalysts showed significant higher activities for total organic carbon (TOC) reduction than those supported on alumina or cerium oxide. Pt was found to be the most active metal for p-chlorophenol oxidation. The activities of noble metal catalysts were found to correlate with heat of formation of metal oxides. CO₂ is the predominant oxidation product with formation of minor p-benzoquinone and acetic acid as intermediate compounds. Possible reaction pathway was also discussed.     

Preparation and characterization of Jatropha Curcas oil based alkyd resin suitable for surface coating

Jatropha Curcas oil was extracted from Jatropha seeds by solvent extraction method. Three different alkyd resins have been developed from Jatropha Curcas oil by varying the amount of phthalic and maleic anhydride. The prepared resins are cured by using methyl-ethyl ketone peroxide (MEKP) as initiator and Co-octoate as an accelerator at 120 °C. The characterizations of the resins for structure establishment is carried out using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (¹H NMR) spectroscopic techniques. The concomitant properties of the cured resins such as acid value, saponification value, viscosity, molecular weight, etc. are also evaluated by standard methods. The cured resins have been tested for chemical resistance, pencil hardness, adhesion, thermal stability and gloss and it can be concluded that the resins may find potential applications in surface coating purposes.     

Kinetic studies on the esterification of free fatty acids in jatropha oil

Kinetic studies have been carried out on the esterification of free fatty acids (FFAs) in jatropha oil with methanol in the presence of sulphuric acid catalyst at 5 and 10 wt% concentrations relative to free fatty acids (0.4–0.8 wt% relative to oil) and methanol–FFA mole ratios ranging from 20:1 to 80:1. It has been found that a 60:1 methanol–FFA mole ratio and 5 wt% catalyst at 60°C and 500 rpm or above provided a final acid value lower than 1 mg KOH/g oil within 60 min. A kinetic model has been proposed with second‐order kinetics for both the forward and backward reactions. The effect of temperature on the reaction rate constants and equilibrium constant has been determined using Arrhenius and von't Hoff equations, respectively. The heat of reaction was found to be ?11.102 kJ/mol.     

Octane number enhancement studies of naphtha over noble metal loaded zeolite catalysts

An Indian industrial naphtha containing mixture of various hydrocarbons belong to n-paraffins, isoparaffins, naphthenes and aromatics falling in C₅ to C₉ carbon range has been studied for its octane boosting through the production of isoparaffins over various Pt loaded zeolite catalysts possessing different acidity and porosity properties. Optimum balance of acid and metal functionalities in 0.6 wt.% Pt loaded on BEA zeolite helped in achieving highest increase in research octane number (RON) from 44 to 80, suitable for gasoline applications, through the production of lower isoparaffins (iC₄-iC₆) along with C₇+ isoparaffins.     

Hydrotreatment of heavy oil from a direct coal liquefaction process on sulfided Ni-W/SBA-15 catalysts

A series of Ni-W catalysts supported on SBA-15 with different pore sizes were prepared by incipient wetness impregnation method and characterized by N₂ adsorption-desorption and X-ray diffraction. The hydrogenation of heavy oil (distillation temperature: 320-340 °C) derived from the direct coal liquefaction process using Shengli coal in the presence of sulfided Ni-W/SBA-15 catalysts with different pore sizes were evaluated at 400 °C and initial H₂ pressure of 5.0 MPa. The results showed that the catalyst preparation method and the pore size of the support had a significant influence on the Ni/W crystallite size, hydrodenitrogenation (HDN) and hydrodearomatization (HDA) activities of coal-derived heavy oil. The larger pore could cause the Ni-W/SBA-15 to form larger Ni-W crystallite. The catalysts with largest pore in the range studied displayed highest HDN and HDA activities for upgrading of the coal-derived heavy oil.     

Hydrodechlorination of tetrachloroethylene over sulfided catalysts: kinetic study

In this work, a commercial sulfided hydrotreatment catalyst (2.8% NiO, 13.5% MoO₃, supported on γ-alumina, supplied by Shell) is compared with different iron sulfide based catalysts. These catalysts were prepared from a by-product (called red mud (RM)) of the bauxite leaching in the Bayer process. Two different activation procedures were tested, both based in dissolving the RM in an acid solution (HCl or HCl+H₃PO₄) followed by a precipitation with ammonia at pH=8 and calcining at 500 °C. All the catalysts were sulfided at 400 °C.

The commercial catalyst was more active than the iron sulfide catalysts in all the range of space times tested. However, considering the low prize of the RM based catalysts, they could be an interesting alternative to the hydrotreatment catalysts. The selectivity for ethane was near 100% for all the catalysts tested.

Kinetics results were successfully modeled with a Langmuir–Hinshelwood model, assuming that the chemisorption of hydrogen (considered as associative) and TTCE occurs over analogous active sites.     

Direct conversion of triglycerides to olefins and paraffins over noble metal supported catalysts

Deoxygenation of methyl esters and triglycerides was studied for production of either α-olefins or diesel components. The reactions were carried out in a reactive distillation fashion in which products are quickly removed from the reaction mixture in flowing He. The effects of He flow rate, reaction temperature, active component and support were studied. PtSnK supported on silica was found to be the best catalyst for selective production of α-olefins. Palm kernel oil and coconut oil were also deoxygenated to produce α-olefins or diesel components, depending on reaction conditions.     

贵金属分子筛催化剂的润滑油脱蜡反应研究

制备了硅铝比不同、载体分别为ZSM-5和β分子筛的贵金属Pd催化剂,并对催化剂进行孔结构和酸性表征。以正十二烷为模型化合物分别评价该系列催化剂的加氢反应性能,同时以含蜡润滑油为原料,考察催化剂对润滑油的加氢脱蜡效果,结果表明,酸性和孔径适宜的ZSM-5贵金属催化剂具有较好的脱除长链大分子蜡的能力。     

Development of monolithic catalysts with low noble metal content for diesel vehicle emission control

The chemical composition of the catalyst containing Mn–Al–O and Pt has been developed on the basis of the synergetic effect of Pt and manganese oxides observed in the HC and CO oxidation reactions. This effect allows decreasing the Pt loading to 0.70 g/L in the catalytic systems of diesel engine exhaust gases and provides high activity in low temperature oxidation of light and heavy hydrocarbons, and high thermal stability. It has been found that the catalytic activity of Pt–Mn–Al monolithic catalysts in butane oxidation and DIESEL tests depends on the Pt precursor and Pt loading. At similar Pt loadings (1.06 g/L), the catalytic activity increases in the order H₂PtCl₆~H₂[Pt(OH)₆] < Pt(NO₂)₂(NH₃)_2. When one Pt precursor is used, the catalytic performance improves with Pt loading increase from 0 to 1.06 g/L, and being nearly constant at higher Pt loading (2.65 g/L).     

硫化铂族金属加氢催化剂的研究进展

硫化铂族金属催化剂为可提高有机液相加氢反应选择性的高效催化剂,能提高含羰基、羟基和卤素等官能团化合物催化加氢反应的选择性,应用广泛。综述了国内外负载型Pt和Pd等硫化贵金属催化剂的制备方法,包括采用H_2S和Na_2S无机硫化以及Ph_2S和DMSO(二甲基亚砜)等有机硫化剂进行硫化;综述了Pt和Pd硫化贵金属催化剂在有机液相催化加氢体系中的应用;并对硫化Pt族金属催化剂的硫化机理和催化机理进行探讨,展望了硫化贵金属催化剂的应用前景。     

Rape oil transesterification over heterogeneous catalysts

This work studies the application of KNO₃/CaO catalyst in the transesterification reaction of triglycerides with methanol. The objective of the work was characterizing the methyl esters for its use as biodiesel in compression ignition motors. The variables affecting the methyl ester yield during the transesterification reaction, such as, amount of KNO₃ impregnated in CaO, the total catalyst content, reaction temperature, agitation rate, and the methanol/oil molar ratio, were investigated to optimize the reaction conditions.The evolution of the process was followed by gas chromatography, determining the concentration of the methyl esters at different reaction times. The biodiesel was characterized by its density, viscosity, cetane index, saponification value, iodine value, acidity index, CFPP (cold filter plugging point), flash point and combustion point, according to ISO norms. The results showed that calcium oxide, impregnated with KNO₃, have a strong basicity and high catalytic activity as a heterogeneous solid base catalyst.The biodiesel with the best properties was obtained using an amount of KNO₃ of 10% impregnated in CaO, a methanol/oil molar ratio of 6:1, a reaction temperature of 65 °C, a reaction time of 3.0 h, and a catalyst total content of 1.0%. In these conditions, the oil conversion was 98% and the final product obtained had very similar characteristics to a no. 2 diesel, and therefore, these methyl esters might be used as an alternative to fossil fuels.     

Combustion of non-halogenated volatile organic compounds over group VIII metal catalysts

Catalytic combustion of volatile organic compounds (VOCs), present in low concentrations (10–1000 ppm) in industrial effluent streams, is a promising air abatement technology. The oxidation of benzene, butanol and ethyl acetate over group VII metal catalysts supported on alumina carriers has been investigated. Pt, Pd and Co were found to be the most active among group VIII metals, while ethyl acetate was found to be the most-difficult-to-oxidize compound. Benzene and ethyl acetate oxidations over Pt/Al₂O₃ were found to be structure sensitive reactions with the turnover frequency (TOF) increasing with increasing mean metal particle size. The presence of chloride on the catalyst surface, originating from chloride-containing metal precursor compounds was found to exert an inhibiting effect on the activity of Pt. Apparent activation energies of the reactions over Pt and Pd catalysts were found to be in the 70–120 kJ/mol range while the reaction order with respect to the VOC was positive in all cases. During oxidation of benzene-butanol mixtures, benzene oxidation was completely suppressed as long as butanol was present in the reaction mixture.