对甲苯磺酸铝催化合成乙酰水杨酸的研究

经复分解反应制得了对甲苯磺酸铝,并用元素分析、IR、TGA等测试技术对产物的组成与结构进行了表针,并将其作为固体酸,用于催化水杨酸与乙酸酐合成乙酰水杨酸的O-酰化反应。实验结果表明,对甲苯磺酸铝对O-酰化反应表现出良好的催化活性,水杨酸与乙酸酐摩尔比1∶2(0.01 mol水杨酸),对甲苯磺酸铝0.15 g,水浴温度75℃,反应时间35 min,乙酰水杨酸平均收率可达87%以上。     

乙酰水杨酸微型化合成实验研究

探讨乙酰水杨酸微型化合成的最佳实验条件。以浓硫酸作催化剂,用乙酸酐与水杨酸进行酰化反应制备乙酰水杨酸,改变反应条件进行实验,重点考察了反应物摩尔数比、反应温度、反应时间及催化剂等条件对反应的影响。乙酰水杨酸微型化合成的最佳实验条件是:乙酸酐和水杨酸的摩尔数比为3∶1,反应温度60~80℃,以浓硫酸作催化剂,反应时间3~5 min。     

对甲苯磺酸催化合成乙酰水杨酸的研究

以水杨酸和乙酸酐为原料，采用对甲苯磺酸作催化剂合成了乙酰水杨酸，考察了影响反应的因素。实验结果表明酰化反应的优化条件为水杨酸：乙酸酐：对甲苯磺酸摩尔比为1：2：0．0153，反应20min，反应温度81～85℃，产率达94．44％。     

氨基磺酸催化合成乙酰水杨酸的研究

以水杨酸和乙酸酐为原料,采用氨基磺酸作催化剂合成乙酰水杨酸。考察了影响反应的因素。结果表明,酰化反应的优化条件为：n（水杨酸）∶n（乙酸酐）∶ n（氨基磺酸）＝1∶ 1.5 ∶0.006 1,反应时间25 min,反应温度（81～85） ℃,产率可达93.34%。     

合成乙酰水杨酸的反应条件的探讨

对乙酰水杨酸"老药新用"的应用现状以及应用前景进行了详细的分析。比较了目前市场上乙酰水杨酸各种合成方法的优劣,设计了适合于工业化的较佳的合成路线,考察了原料物质的量之比、催化剂用量、反应温度、反应时间对反应收率的影响,进一步优化了合成工艺。经过实验数据的处理与分析,采用O-酰基化反应合成乙酰水杨酸的适宜条件为:无水环境下,对甲苯磺酸为催化剂,n(水杨酸)∶n(乙酸酐)=1∶2.0;反应温度为85℃和反应时间为30 min时,乙酰水杨酸的收率高于97%。所得样品符合《中国药典》和《美国药典》中乙酰水杨酸的质量要求,能够用于合成乙酰水杨酸。     

合成阿司匹林的催化方法综述

由水杨酸和乙酸酐经酰化反应合成的酯类化合物乙酰水杨酸即为阿司匹林,是一种非甾体抗炎药,在医药领域的应用非常广泛。综述了水杨酸和乙酸酐在有机酸催化、无机酸催化、有机碱催化、无机碱催化、微波催化、超声催化、离子液体催化、碘单质催化下合成阿司匹林的方法,并分析了每种催化方法的优缺点,为今后合成阿司匹林的催化方法研究提供参考。     

尿素催化合成乙酰水杨酸

以水杨酸和乙酸酐为原料,采用尿素作催化剂合成乙酰水杨酸。考察了温度、尿素用量、n(水杨酸)∶n(乙酸酐)和时间对反应的影响。正交试验结果表明,较适宜的反应条件为:n(水杨酸)∶n(乙酸酐)=1∶3,尿素用量为水杨酸质量的5%,反应温度85℃,反应时间60 min,此条件下,乙酰水杨酸收率达94.06%。     

吡啶催化合成乙酰水杨酸的研究

用吡啶催化剂,以水杨酸和乙酸酐为原料合成乙酰水杨酸.结果表明,当水杨酸用量为2.0g,乙酸酐用量为5.9 mL,吡啶用量为水杨酸质量的5%时,80℃反应30min,纯化乙酰水杨酸收率可达80.2%,且吡啶是合成乙酰水杨酸的优良催化剂.     

乙酰水杨酸合成工艺研究

研究了以冰乙酸作为催化剂,由水杨酸和乙酸酐合成乙酰水杨酸。较系统地研究了催化剂种类、物料比、反应温度、反应时间等因素对乙酰水杨酸收率的影响。结果表明,冰乙酸是一种比较好的反应催化剂。较佳反应条件为:水杨酸用量为2g,V(冰醋酸)=3mL,n(水杨酸)/n(乙酸酐)=1∶3.5,反应温度70℃,反应30min,乙酰水杨酸收率可达91.23%。     

碳酸钠催化微波合成阿司匹林的方法探索

以水杨酸和乙酸酐为原料,采用无水碳酸钠作为催化剂经O-酰化反应合成了阿司匹林。比较了微波合成法与传统浓硫酸催化方法对目标化合物合成的影响,探讨了催化剂的结构特征及反应条件对合成产物的影响。结果表明,微波合成法具有操作简单、时间短、对环境和设备影响小、产品质量好、适合绿色化学合成的要求等优点。     

羊毛脂琥珀酸酯磺酸盐加脂剂的制备及性能

将等物质的量的羊毛脂和马来酸酐在 6 0℃加热 2 0min ,加入催化剂对甲苯磺酸 ,在 10 0℃反应 3h ,可得到羊毛脂琥珀酸酯。调节pH值至 6～ 7,加入NaHSO3 饱和水溶液 ,反应 1h ,85℃时反应 2h ,最后升温并在减压下除去水分。向产物中加适量的过氧化氢 ,将未反应的亚硫酸氢钠氧化成硫酸钠 ,得羊毛脂琥珀酸酯磺酸盐。将其与氯化石蜡、硬脂酸聚氧乙烯酯及非离子表面活性剂复配 ,制得AS结合型加脂剂。透射电镜照片显示加脂剂乳液粒子尺寸为 0 5 μm以下 ,且分布均匀 ,产品具有良好的水分散性、耐酸性、耐盐性及良好的加脂性能     

Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

Sulfonic acid functionalized mesoporous silica based solid acid catalysts with different morphology were designed and fabricated. The synthesized materials were characterized by various physicochemical and spectroscopic techniques like scanning electron microscope-energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller surface area, thermogravimetric analysis and n-butylamine acidity. The shape of catalysts particles plays an important role in its activity. The sulfonic acid functionalized mesoporous silica catalysts of spherical shape and the cube shape were assessed for catalytic activity in biodiesel production. The catalytic biodiesel production reaction over the catalysts were studied by esterification of free fatty acid, oleic acid with methanol. The effect of various reaction parameters such as catalyst concentration, acid/alcohol molar ratio, catalyst amount, reaction temperature and reaction time on catalytic activity were investigated to optimize the conditions for maximum conversion. It was sulfonated cubic shape mesoporous silica which exhibited better activity as compared to the spherical shape silica catalysts. Additionally, the catalyst was regenerated and reused up to three cycles without any significant loss in activity. The present catalysts exhibit superior performance in biodiesel production and it can be used for the several biodiesel feedstock’s that are rich in free fatty acids.     

Sulfonated rice husk ash (RHA-SO3H): A highly powerful and efficient solid acid catalyst for the chemoselective preparation and deprotection of 1,1-diacetates

Rice husk ash (RHA), as a source of amorphous silica, was treated with chlorosulfonic acid and sulfonated rice husk ash (RHA-SO₃H) as a highly powerful solid acid catalyst was obtained and characterized with a variety of techniques including IR, TGA, SEM, XRD, pH analysis, Hammett acidity function and BET method. This solid acid showed excellent catalytic activity for the protection and deprotection of aldehydes with Ac₂O at room temperature under solvent free conditions. The procedure gave the products in excellent yields in very short reaction times and good to high yields. Also this catalyst can be reused for several times without loss of its catalytic activity.     

Friedel Crafts acylation of aromatic compounds over arenesulfonic containing mesostructured SBA-15 materials

Arenesulfonic modified mesostructured SBA-15 is shown as an active catalyst for acylation of aromatic compounds using acetic anhydride as acylating agent. Arenesulfonic acid-centers anchored on the pore surface of a mesostructured SBA-15 material show a greater activity (normalised on the concentration of sulfonic groups) as compared to other homogeneous and heterogeneous sulfonated catalysts and even in solventless conditions. This high activity is accompanied with a remarkable thermal stability of the acid centers, without leaching of sulfur species during the reaction. Moreover, an increase of the amount of arenesulfonic centres does not modify the activity of the material per acid center. Thus, this work introduces a new application of these sulfonated mesostructured materials, not described in literature up to now.     

微波辐射固体酸催化合成邻苯二甲酸二丁酯的研究

以硅胶担载对甲苯黄酸 (PTSA)作催化剂 ,采用微波技术 ,邻苯二甲酸酐和正丁醇直接酯化合成邻苯二甲酸二丁酯。最佳反应条件为 :苯酐和正丁醇的摩尔比为 0 .0 2∶ 0 .0 5 ,PTSA担载质量分数为 16 .2 %的催化剂用量 1.2 g,微波功率 5 6 0 W,微波辐射时间 2 80 s,产率可达 98%。催化剂易分离 ,且可重复使用     

新型固体磺酸催化合成苹果酯的研究

以活性炭磺化制得新型固体磺酸磺化炭为催化剂,对乙酰乙酸乙酯和乙二醇合成苹果酯的催化工艺进行了系统研究。讨论了酯醇比、催化剂用量、反应时间、带水剂用量对酯化率的影响。最佳反应条件为:n(乙酰乙酸乙酯):n(乙二醇)=1:1.8,催化剂用量为乙酰乙酸乙酯质量的2%,带水剂用量为20mL,反应时间3h。在优化条件下反应,苹果酯收率达到93.1%,选择性接近100%。实验表明,磺化炭是合成苹果酯的优良催化剂,与其他酸催化剂相比,它还具有活性高、用量少、无污染等突出的优点。     

Catalytic wet air oxidation of carboxylic acids at atmospheric pressure

Catalytic wet air oxidation of carboxylic acids (maleic acid, oxalic acid and formic acid) was carried out in a batch reactor operated at 160 psi or atmospheric pressure. Pt/Al₂O₃ and the sulfonated poly(styrene-co-divinylbenzene) resin were used as catalysts. Maleic acid was proved to be a refractory substance which could not be oxidized on the Pt/Al₂O₃ catalyst at all atmoshperic pressure, and needed high pressure and high temperature operation for its oxidation. On the contrary, oxalic acid and formic acid were readily oxidized into carbon dioxide and water at 353 K and atmospheric pressure. The pathways of maleic acid oxidation were proposed, and the conversion of maleic acid into oxalic acid was the rate-determining step. When the sulfonated resin catalyst was present together with the Pt/Al₂O₃ catalyst, maleic acid could be oxidized at 353 K and atmospheric pressure. The sulfonated resin catalyst was suggested to hydrolyze maleic acid into readily oxidizable compounds.     

Solid acids as substitutes for sulfuric acid in the liquid phase nitration of toluene to nitrotoluene and dinitrotoluene

Our results demonstrate that sulfuric acid supported on preshaped silica is a good catalyst for the nitration of toluene to dinitrotoluene using 65 wt.% nitric acid with respect to catalyst performance (activity, selectivity, regenerability) and catalyst handling (storage, stirring, separation). It is imperative to carefully control the water content of the catalyst prior to reaction in order to obtain high activity. The reusability of the catalyst without compromising performance has been demonstrated. Non-polar solvents seem to be required in order to prevent dissolution of the impregnated acid. Hence, the application of acetic anhydride as a solvent with potential water trapping ability was unsuccessful. Solvent-free operation is limited by the necessity to maintain a mixture that can be stirred. Hence, a maximum conversion of about 30% is achievable for the nitration of nitrotoluene to dinitrotoluene in one reaction cycle.     

Methane Partial Oxidation Using A (La0.6Sr0.4)(Ga0.8Mg0.05Co0.15)O3–δ Membrane

A novel sulfonated carbon composite solid acid was successfully prepared by the pyrolysis of a polymer matrix impregnated with glucose followed by sulfonation. The title catalyst has higher acid site density, better esterification activity of both small and large free fatty acids (acetic acid and palmitic acid), and better reusability than the previously reported carbon-based catalyst prepared by sulfonating pyrolyzed sugar. This catalyst also exhibited higher esterification activity than tungstated zirconia (WZ) and Silica-Supported Nafion (Nafion^®SAC-13). The higher activity of the sulfonated carbon composite solid acid catalyst was clearly due to the presence of a much higher acid site density than any of the other catalysts.     

富马酸二甲酯的合成工艺研究

以马来酸酐和甲醇为原料,用磷钨酸作酯化催化剂制得马来酸二甲酯,再用硫脲作异构化催化剂制得富马酸二甲酯。通过正交实验确定出最佳工艺条件为:甲醇∶马来酸酐的摩尔比为8∶1,催化剂磷钨酸的用量是马来酸酐用量的10%,酯化时间为5h,催化剂硫脲用量为马来酸酐用量的2.5%,异构化时间为20～30min,产率可达87.8%。