乙炔羰基化合成丙烯酸甲酯的研究

以乙炔、一氧化碳和甲醇为原料,卤化镍为主催化剂,羰基化合成丙烯酸甲酯,考察其在不同的反应温度、反应初始压力、原料配比、反应时间和催化剂用量下对反应结果的影响,确定最优的工艺条件。实验表明：以甲醇为溶剂,在185℃左右和5．2～5．5MPa的条件下,n（甲醇）：n（乙炔）：n（CO）=5．5～6．2：1：1,催化剂用量0．85wt％～0．9wt％,反应4～5h,丙烯酸甲醣的收率（相对乙炔）达到90％以上。     

Catalytic synthesis of n-propyl acrylate from acetylene,carbon monoxide and n-propanol under pressure

The high-pressure synthesis of n-propyl acrylate from acetylene, carbon monoxide and n-propanol has been studied in detail. Nickel iodide–silica gel (Ni : SiO₂ = 50 : 50) and nickel acetate–silica gel (Ni : SiO₂ = 50 : 50) were the most active catalysts (yields 58.78%, 55.54% respectively on acetylene input basis). Besides n-propyl acrylate, the reaction product contains acrylic acid, acetaldehyde, liquid hydrocarbons, carbon dioxide, hydrogen, ethylene and other unsaturated hydrocarbons.     

Reaction between methanol and acetic acid catalyzed by SiO2‐supported V‐P‐O catalyst in oxygen atmosphere

SiO₂‐supported V‐P‐O catalysts prepared by the incipient‐wetness impregnation method beginning with ammonium metavanadate and phosphoric acid were used in the catalytic reaction between methanol and acetic acid in an oxygen atmosphere. The SiO₂‐supported V‐P‐O catalysts were composed of VOPO₄ and (VO)₂P₂O₇ phases. Both the acidic and alkaline sites were co‐present in the catalysts. The vanadium species catalyzed the oxidation of methanol to formaldehyde. The V‐P‐O(20–30 wt%)/SiO₂ catalysts with a P/V mole ratio of 2:1 exhibited higher catalytic activity for the formation of acrylic acid and methyl acrylate with a total selectivity of ～28 % at 380 °C. The acid sites of the catalysts also catalyzed the formation of methyl acetate with a selectivity of ～65 %. Methanol can be an alternative to formaldehyde for the synthesis of both acrylic acid and methyl acrylate through the aldol condensation reaction.     

Catalytic synthesis of n-butyl acrylate from acetylene,carbon monoxide and n-butanol under high pressure

The reaction of acetylene, carbon monoxide and n-butanol to form n-butyl acrylate has been studied with several catalysts under a wide range of operating variables. Nickel iodide-silica gel (Ni:SiO₂ = 50:50) is the most effective catalyst with 80.3% conversion of acetylene to the ester. Nickel acetate-silica gel (Ni:SiO₂ = 50:50) is also a good catalyst (63% conversion). Other reaction products found were carbon dioxide, acrylic acid, acetaldehyde, saturated and unsaturated hydrocarbons, and polymeric products.     

催化环氧乙烷氢甲酯化的催化体系研究

以Co2(CO)8为催化剂,甲醇为溶剂,在一定CO压力下,催化环氧乙烷氢甲酯化合成3-羟基丙酸甲酯。考察了不同配体、催化剂/配体的摩尔比、温度、CO压力、甲醇用量对环氧乙烷氢甲酯化反应的影响。得到较佳合成工艺条件为:咪唑为配体、n(催化剂)∶n(配体)=1∶1.5、反应温度75℃、反应压力6.0 MPa、V(甲醇)∶V(环氧乙烷)=5∶1。在该优化条件下,环氧乙烷转化率为92.24%,3-羟基丙酸甲酯收率达84.35%。     

Condensation of alcohol over solid-base catalyst to form higher alcohols

Condensations of various primary alcohols (C₂-C₅) with methanol were carried out at atmospheric pressure over various metal oxides having a solid-base property. The reactions gave one or two carbon higher alcohol than the reacted primary alcohol. MgO catalyst was most active for the reaction and yielded the alcohol products in high selectivity (> 80%). Based on the results of the exchange reaction between methyl hydrogen of methanol over MgO surface, it is concluded that a rapid hydride transfer between adsorbed alcohol and adsorbed carbonyl is responsible for the selective formation of alcohols.     

Palladium-catalyzed hydroesterification of propene into methyl 2-methylpropanoate at room temperature and atmospheric pressure. Influence of various parameters on the activity and selectivity of the reaction

The hydroesterification of propene into methyl 2-methylpropanoate by homogeneous catalytic systems consisting of palladium, copper, oxygen and acid is investigated under very mild conditions (room temperature, atmospheric pressure). From experimental results it appears that: (i) very high selectivities (up to 95%) into the branched ester can be obtained; (ii) the presence of CuCl₂ and O₂ as final reoxidant of palladium is required; (iii) the activity increases with partial pressure of O₂ in the gas phase. This revised version was published online in July 2006 with corrections to the Cover Date.     

Palladium-catalyzed hydroesterification of olefins with isosorbide in standard and Brønsted acidic ionic liquids

The palladium catalyzed hydroesterification of 1-octene with isosorbide was studied in standard and Brønsted acidic ionic liquids as reaction media. High conversions and selectivities towards the targeted isosorbide diesters have been achieved by using a catalytic system composed of Pd(OAc)₂ and trisulfonated triphenylphosphine dissolved in 1-(4-sulfonic acid)-butyl-3-methylimidazolium tosylate. The catalytic phase can be reused several times without any significant decrease in activity and selectivity.     

Influence of preparation method on performance of Cu(Zn)(Zr)-alumina catalysts for the hydrogen production via steam reforming of methanol

The selective production of hydrogen via steam reforming of methanol (SRM) was performed using prepared catalysts at atmospheric pressure over a temperature range 200–260^∘C. Reverse water gas shift reaction and methanol decomposition reactions also take place simultaneously with the steam reforming reaction producing carbon monoxide which is highly poisonous to the platinum anode of PEM fuel cell, therefore the detailed study of effect of catalyst preparation method and of different promoters on SRM has been carried out for the minimization of carbon monoxide formation and maximization of hydrogen production. Wet impregnation and co-precipitation methods have been comparatively examined for the preparation of precursors to Cu(Zn)(Al₂O₃) and Cu(Zn)(Zr)(Al₂O₃). The catalyst preparation method affected the methanol conversion, hydrogen yield and carbon monoxide formation significantly. Incorporation of zirconia in Cu(Zn)(Al₂O₃) catalyst enhanced the catalytic activity, hydrogen selectivity and also lower the CO formation. Catalyst Cu(Zn)(Zr)(Al₂O₃) with composition Cu/Zn/Zr/Al:12/4/4/80 prepared by co-precipitation method was the most active catalyst giving methanol conversion up to 97% and CO concentration up to 400 ppm. Catalysts were characterized by atomic absorption spectroscopy (AAS), Brunauer-Emett-Teller (BET) surface area, pore volume, pore size and X-ray powder diffraction (XRPD). The XRPD patterns revealed that the addition of zirconia improves the dispersion of copper which resulted in the better catalytic performance of Cu(Zn)(Zr)(Al₂O₃). The time-on-stream (TOS) catalysts stability test was also conducted for which the Cu(Zn)(Zr)(Al₂O₃) catalyst gave the consistent performance for a long time compared to other catalysts.     

Influence of preparation method on performance of Cu(Zn)(Zr)-alumina catalysts for the hydrogen production via steam reforming of methanol

The selective production of hydrogen via steam reforming of methanol (SRM) was performed using prepared catalysts at atmospheric pressure over a temperature range 200–260^°C. Reverse water gas shift reaction and methanol decomposition reactions also take place simultaneously with the steam reforming reaction producing carbon monoxide which is highly poisonous to the platinum anode of PEM fuel cell, therefore the detailed study of effect of catalyst preparation method and of different promoters on SRM has been carried out for the minimization of carbon monoxide formation and maximization of hydrogen production. Wet impregnation and co-precipitation methods have been comparatively examined for the preparation of precursors to Cu(Zn)(Al₂O₃) and Cu(Zn)(Zr)(Al₂O₃). The catalyst preparation method affected the methanol conversion, hydrogen yield and carbon monoxide formation significantly. Incorporation of zirconia in Cu(Zn)(Al₂O₃) catalyst enhanced the catalytic activity, hydrogen selectivity and also lower the CO formation. Catalyst Cu(Zn)(Zr)(Al₂O₃) with composition Cu/Zn/Zr/Al:12/4/4/80 prepared by co-precipitation method was the most active catalyst giving methanol conversion up to 97% and CO concentration up to 400 ppm. Catalysts were characterized by atomic absorption spectroscopy (AAS), Brunauer-Emett-Teller (BET) surface area, pore volume, pore size and X-ray powder diffraction (XRPD). The XRPD patterns revealed that the addition of zirconia improves the dispersion of copper which resulted in the better catalytic performance of Cu(Zn)(Zr)(Al₂O₃). The time-on-stream (TOS) catalysts stability test was also conducted for which the Cu(Zn)(Zr)(Al₂O₃) catalyst gave the consistent performance for a long time compared to other catalysts.     

甲酸甲酯与甲醇钠合成碳酸二甲酯反应研究

通过对不同溶剂存在下甲酸甲酯与甲醇钠非催化合成碳酸二甲酯反应的研究,发现四氢呋喃比质子性溶剂甲醇和极性非质子性溶剂二甲基甲酰胺等更适合该合成反应,它兼有两者的优点,对两者的缺点又有不同程度的克服。本文重点考察了甲醇和一氧化碳对催化合成DMC反应的影响,结果发现当反应体系中有甲醇存在时,甲醇会与甲氧基负离子通过氢键结合,降低甲氧基负离子的亲核活性,影响反应生成DMC的速率。与甲醇不同,一氧化碳能有效抑制甲酸甲酯的分解反应,当使用CO/O2作氧化剂时,得到了较好的DMC收率和选择性。     

Low-Temperature Methanol Synthesis in Catalytic Systems Composed of Copper-Based Oxides and Alkali Alkoxides in Liquid Media: Effects of Reaction Variables on Catalytic Performance

Catalytic systems composed of copper-based oxides and alkali alkoxides are tested for low-temperature methanol synthesis in liquid phases, which involves carbonylation of methanol to methyl formate and consecutive hydrogenation of methyl formate to methanol. The effects of reaction variables on the catalytic performance are investigated under the conditions of 373-423K temperature and 1.5-5.0 Mpa pressure. The combined catalytic systems of copper chromite and potassium methoxide exhibit excellent activities for the production of methanol. Higher values of reaction temperature, initial pressure, catalyst loading, and H₂/CO ratio of the feed gas lead to higher methanol productivity. In particular, the reaction temperatures and the feed gas compositions strongly influence the catalytic performance. No methanol is formed when employing a feed gas containing 2% CO₂. The catalytic systems are deactivated in a short period even in a CO₂-free feed gas, due to the consumption of the alkoxide component. Alkali alkoxides are consumed through reactions with trace amounts of CO₂ and H₂O which are formed as by-products during the course of the runs. The results also suggest that the hydrogenation step of methyl formate over copper chromite is greatly accelerated in the presence of the alkali alkoxide.     

乙炔羰基化合成丙烯酸甲酯工艺的研究

以乙炔、甲醇为原料,卤化镍为主催化剂,羰基化合成丙烯酸甲酯,考察了反应温度、反应压力、反应时间、搅拌转速等因素对反应的影响,确定最佳的工艺条件。结果表明:在185℃和5.5MPa下,搅拌转速600r/min,反应3h,乙炔的选择性为96.59%,丙烯酸甲酯的收率(相对乙炔)达到93.71%。     

Production of biodiesel by esterification of natural fatty acids over modified organoclay catalysts

Biodiesel has been produced by esterification of natural fatty acids with methanol in the presence of a modified bentonite with 1-benzyl-1H-benzimidazole-based Brønsted acidic ionic liquids as catalysts. The effect of reaction temperature, type and amount of catalyst, molar ratio and reaction time was investigated. The results showed that MB3B (bentonite modified with 3,3′-(butane-1,6-diyl)bis(6-sulfo-1-(4-sulfobenzyl)-1H-benzimidazolium) hydrogensulfate) has the highest catalytic activity and best recyclability under the optimized reaction conditions. Thus, this modified bentonite is able to catalyze the esterification of oleic acid to its methyl ester in 6 h with yields of more than 92%. The catalytic activity of MB3B for the esterification of natural other fatty acids and alcohols has also been studied.     

Methyl formate as a new building block in C1 chemistry

Methyl formate has been proposed as a building block molecule in C₁ chemistry. This paper examines the potential of this concept by reviewing the processes of synthesis of the molecule and the chemical reactions that it undergoes. Methyl formate can be produced by a variety of routes from a number of feedstocks. The reaction between methanol and carbon monoxide is an efficient process, used commercially. Combination of an efficient synthesis of methyl formate and its facile decomposition allows the molecule to be used as a means for separation, storage and transport of synthesis gas. The number of reactions that convert methyl formate to other chemicals is large. In particular, the synthesis of large volume chemicals such as methanol, acetic acid and ethylene glycol deserves serious consideration. Examples are provided of applications in the chemical and energy industries involving methyl formate. The reactions involved in the synthesis and transformation of methyl formate are mostly catalytic in nature. Many currently known catalytic systems are not efficient to compete with conventional routes involving methanol or synthesis gas. Fundamental research to understand the catalytic chemistry involved is highly desirable in order to improve the performance of the catalytic systems.     

Producing Fatty Acid Methyl Esters from Free Fatty Acids with Ionic Liquids as Catalyst

Three Brønsted acidic imidazole dicationic ionic liquids (ILs) with different length of alkyl chains, [C_n(Mim)₂][HSO₄]₂ (n = 3, 6, 12), were prepared and used as catalyst for the esterification reaction of free fatty acids and methanol. Taking oleic acid as model acid, the catalytic performances of the synthesized ILs for the esterification were evaluated. The main physicochemical properties of the ILs, thermal stability, acidity, solubility in common solvents, and causticity on Austenitic stainless steel 316, were examined. [C₃(Mim)₂][HSO₄]₂ demonstrated the highest catalytic activity and enabled to assess the preliminary optimum esterification condition of oleic acid and methanol. Under optimized reaction conditions, the yield of oleic acid methyl ester was up to 95 %. The ILs have great potential as catalysts for producing fatty acid methyl esters from long‐chain free fatty acids.     

Acetic Acid from the Carbonylation of Chloride Methane Over Rhodium Based Catalysts

A new route for the indirect conversion of methane that makes use of the latest advance in methyl chloride production is reported. Acetic acid was produced from the carbonylation of methyl chloride by carbon monoxide over a variety of catalysts. The presence of promoters was crucial for the carbonylation reaction. The yield of acetic acid reached 84.7% with RhCl₃ as catalyst and PPh₃/KI as promoters. The effects of reaction temperature, carbon monoxide pressure, and reaction time were investigated. The possible reaction mechanism was discussed.     

The promoting effect of alcohols in a new process of low-temperature synthesis of methanol from CO/CO2/H2

The catalytic promoting effects of eleven different alcohols, as reaction medium, on the synthesis of methanol from feed gas of CO/CO₂/H₂ on Cu/ZnO solid catalyst were investigated. Added alcohol altered the reaction route to realize a low-temperature synthesis method where formate was an intermediate. Many alcohols showed catalytic promoting effect for methanol formation at temperature as low as 443 K, remarkably lower than that in the present industrial ICI process.     

Reduction of Vegetable Oil-Derived Fatty Acid Methyl Esters toward Fatty Alcohols without the Supply of Gaseous H2

An alternative route to the conventional one for fatty alcohol synthesis was investigated. It was possible to synthesize lauryl alcohol from methyl laurate via reduction by transfer of hydrogen and hydride in liquid phase, in noncatalytic reactions and without the supply of H₂ gaseous. Pure NaBH₄ or alumina-supported NaBH₄ and methanol were used as co-reactants and 100% fatty alcohol selectivities were achieved. The aim of supporting the metal hydride was to increase its stability and achieve the full recovery of the solid at the end of reaction. When alumina-supported NaBH₄ was used, a final fatty alcohol yield of 93% was achieved. The use of methanol and NaBH₄ in amounts higher than stoichiometric is important to generate alkoxyborohydride anions which act as better reducing species than NaBH₄. The reaction conditions effect was investigated and the role of short carbon chain alcohol structure was elucidated. The effect of fatty acid methyl ester structure was also studied. Fatty acid methyl esters with shorter carbon chain length and without unsaturation (methyl laurate, methyl myristate) were easily reduced using NaBH₄/Al₂O₃ and methanol reaching high conversions and fatty alcohol selectivities. Unsaturated fatty acid methyl ester with longer carbon chain (methyl oleate) introduced steric hindrance which disfavoured interaction between ester and reducing solid surface and fatty acid methyl ester conversion was noticeably lower. A reaction mechanism based on alkoxyborohydride anions as the actual reducing species was proposed. This mechanism fully interprets results obtained during fatty acid methyl ester reduction using short carbon chain alcohols and metal hydride.     

Relation between preparation,porosity and selectivity of CuO-ZnO-MeO x catalysts in the synthesis of alcohol mixtures

Some relations between the preparation of modified CuO-ZnO catalysts, their structural properties and their catalytic performance in the hydrogenation of carbon monoxide have been demonstrated. The different activities in the formation of higher alcohols have been attributed to an influence of the porosity on chain growth. The coupling or insertion of C₁ intermediates seems to be favoured by an increasing surface coverage with C₁ intermediates due to a transport limitation of methanol production. The pore size distribution of the catalysts has been varied by different calcination, thermal ageing, CuO/ZnO ratios, the method of promoting with Al₂O₃ and pelleting.