三氟甲磺酸催化便捷高效合成2,4-滴丁酯除草剂

以2,4-二氯苯氧乙酸与正丁醇为原料,三氟甲磺酸为催化剂,催化合成2,4-滴丁酯,考察了醇酸摩尔比、反应时间及催化剂用量等对反应的影响。结果表明,合成2,4-滴丁酯的最佳反应条件是:正丁醇与2,4-二氯苯氧乙酸的摩尔比为3∶1,催化剂用量为0.2%(占2,4-二氯苯氧乙酸摩尔量),回流反应8 h,在此条件下,酯化率达97.1%。     

Polycondensation of tetramethyldisiloxane 1,3-diol catalyzed by trifluoromethanesulfonic acid

The kinetics of polycondensation of tetramethyldisiloxane 1,3-diol (HD₂OH) have been followed by stopping the reaction at increasing times (by neutralization of the acid and trimethylsilylation of the silanol end-groups). Analyses of the linear and cyclic oligomers and of the higher polymer have been made by gas–liquid chromatography and by steric exclusion chromatography. At the beginning of the reaction (e. g. between 1 min and 1 h) the main products are linear oligomer H(D)_2nOH and D₄ (formed by cyclization of HD₄OH). There are only very small amounts of large cycles. Linear high polymer is then formed slowly together with increasing amounts of cycles D₅, D₆, D₇, …, formed by backbiting reactions. After 24h, the yield of D₄ is 40–50% and that of linear polymer 40–30% (M_peak × 10⁴–10⁵). With disilanol concentration 0.45–0.9 mol liter^?1 and CF₃SO₃H concentration about 10^?3 mol liter^?1, the reaction is very rapid during 1–2 min and the medium becomes heterogenous with the formation of an inverse water emulsion. The reaction then slows down considerably, most of the hydrated acid being trapped in the water droplets. Silanol consumption is second order in [SiOH] and first order [TfOH]_o. Polymerizations made in polar and non-polar solvents have similar rates, which however increase moderately in the order toluene<1,2-dichloro-ethane<dichloromethane, this corresponding to an increasing solubility of the hydrated acid in these solvents. Polycondensation occurs in the organic phase near the interface, either by esterification of silanol followed by heterccondensation or by homocondensation catalyzed by the hydrated acid (or both).     

Use of trifluoromethanesulfonic acid as catalyst for the cyclization of polyisoprene

In this study, trifluoromethanesulfonic acid was employed as catalyst for the cyclization of polyisoprene. From ¹H nuclear magnetic resonance spectroscopy and gel permeation chromatography investigations, cyclization was confirmed, and the molecular structure variation of polyisoprene during cyclization reaction was determined. With the comparison to that catalyzed by other strong acids (methanesulfonic acid), polyisoprene was cyclized with much higher efficiency, using trifluoromethanesulfonic acid as catalyst. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3666–3669, 2006     

三氟甲磺酸催化1-己烯齐聚反应的研究

使用三氟甲磺酸作催化剂对1-己烯齐聚反应进行研究。考察三氟甲磺酸催化剂用量、反应温度和反应时间等工艺条件对产物聚α-烯烃收率的影响。确定了最佳工艺条件：催化剂用量1.0 mL,反应温度50 ℃,反应时间3 h,此条件下,1-己烯转化率约为90%,产物主要是二聚物、三聚物、四聚物和五聚物,没有裂解产品。为进一步工业化开发聚α-烯烃合成油提供了基础数据。     

Carbonylation of formaldehyde catalyzed by p-toluenesulfonic acid

A catalytic system consisting of p-toluenesulfonic acid, a transition metal complex such as CF₃SO₃Ag, and a solvent exhibits a high catalytic performance for the carbonylation of formaldehyde, followed by esterification with methanol, to produce methyl glycolate. The catalytic performance is significantly improved by using the ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, instead of organic solvents. This catalytic system shows higher yield of methyl glycolate at relatively low CO pressure in comparison to solid acid catalysts. The present system provides a potential process for synthesizing methyl glycolate via carbonylation of formaldehyde in much low corrosion in comparison to the previous system including strong inorganic liquid acids as solvents and catalysts.     

三氟甲磺酸催化合成柠檬酸酯

利用一种新型高效绿色催化剂三氟甲磺酸(CF3SO3H)合成绿色增塑剂柠檬酸三丁酯,结果表明该催化剂用量少(占柠檬酸的0.1%),反应时间短(5 h)。研究了该催化剂合成乙酰柠檬酸酯的一体化工艺,实现了无须精制柠檬酸三丁酯,直接从柠檬酸出发制得乙酰柠檬酸三丁酯,产率高(两步87.1%),纯度高(99.1%),大幅简化了生产工艺和成本且环保,适合工业化。同时,研究了CF3SO3H催化合成丙酰、丁酰柠檬酸酯类产品的一体化工艺。     

Melt polycondensation of L‐lactic acid catalyzed by 1,3‐dialkylimidazolium ionic liquids

BACKGROUND: In syntheses of biodegradable and bioresorbable polymers, efficient metal‐free catalysts are very desirable as the resulting products may be more biocompatible. As an attempt to find new metal‐free catalysts, 1,3‐dialkylimidazolium salts, the most commonly used ionic liquids or organic melt salts, were used as single‐component catalysts in the melt polycondensation of L ‐lactic acid for the first time. The resulting poly(L ‐lactic acid) (PLLA) was characterized using gel permeation chromatography, ¹³C NMR, DSC and polarimetry. RESULTS: It has been found that less bulky substituents on the imidazolium ring are conducive to catalytic activity. PLLA with molar mass of about 20 000 g mol^?1 was synthesized at high yield (over 70%) in the presence of various 1,3‐dialkylimidazolium salts. The product exhibits satisfactory color (white to slightly yellow), optical purity (89–95%) and crystallinity (40–55%). A possible catalytic mechanism is proposed. CONCLUSION: As compared with the well‐known binary catalyst system SnCl₂ · 2H₂O/toluene sulfonic acid, the catalysts used in this investigation are better in terms of increasing PLLA yield and preventing discoloration and comparable in terms of racemization. Copyright © 2008 Society of Chemical Industry     

氨基磺酸催化甲醛和甲酸甲酯偶联反应的研究

在釜式反应器中研究了氨基磺酸催化甲醛和甲酸甲酯偶联反应，考察了反应温度、反应时间、原料配比和催化剂用量等因素对乙醇酸甲酯和甲氧基乙酸甲酯生成量的影响，最佳反应条件为: 反应温度150～160 ℃，反应时间4 h，n（甲醛）：n（甲酸甲酯）=05，在此条件下得到最大的乙醇酸甲酯和甲氧基乙酸甲酯的生成量，总生成量达到2134 mmol·(g-cat)-1。与其他催化剂的性能进行对比发现，氨基磺酸对催化甲醛和甲酸甲酯偶联反应显示出较好的催化性能。     

固体酸催化假紫罗兰酮合成紫罗兰酮研究进展

固体酸催化剂可成为制备紫罗兰酮的环境友好型催化剂,综述金属盐、阳离子交换树脂、固体超强酸、分子筛和杂多酸等固体酸在催化假紫罗兰酮环化反应中的应用,固体超强酸是目前的研究热点,存在易失活、不易保存和稳定性不足等问题。通过对催化剂载体改性、加入其他金属或氧化物形成多组元固体超强酸、引入稀土元素或特定的分子筛改性制备固体超强酸以及引入纳米级金属氧化物制备出纳米型固体超强酸等,这些均可为催化剂提供合适的比表面积、增加酸中心密度、增加酸种类型、增加稳定性和提高机械强度。     

1,3-二元脂肪醇萃取硼酸的平衡特性

基于1,3-二元脂肪醇的溶剂萃取法在盐湖卤水提硼方面有广阔的应用前景,系统研究了两种1,3-二元脂肪醇萃取剂:2-乙基-1,3-己二醇(EHD)和2-丁基-2-乙基-1,3-丙二醇(BEPD)对硼酸的萃取性能,分别考察了萃取剂浓度、原料液pH、硼酸浓度、氯化镁浓度以及温度等因素对硼酸分配系数的影响。实验结果表明,温度为303.15 K,原料液中硼酸浓度为0.0185 mol·L^-1,EHD和BEPD甲苯溶液中浓度均为0.4 mol·L^-1时,硼酸的分配系数分别达到9.43和8.25。高浓度的萃取剂和较低的原料液pH条件对提高分配系数有利;分配系数随原料中硼酸浓度和反应温度的升高而降低,1,3-二元脂肪醇萃取硼酸的过程为放热过程;氯化镁存在下的盐析效应也有利于硼酸的萃取分配。     

Efficient synthesis of novel 1,3-diyne-based sulfonamides using CuCl2/Et3N as a robust catalytic system

An efficient and practical synthesis of 1,3-diyne-based sulfonamides using CuCl₂/Et₃N as a catalytic system is disclosed. Mild reaction conditions, atom-economy and high yields (50–91%) make this method an attractive option for the preparation of 1,3-diyne-based sulfonamide derivatives.     

杂多酸催化合成丁二酸二丁酯研究

采用均匀设计，以Keggin型磷钨酸为催化剂，甲苯为带水剂，得到了合成丁二酸二丁酯的最佳工艺条件为：醇酸物质的量比3．0：1，催化剂量为酸质量的1．1％，带水剂量为反应体系总质量的22％，反应时间2h，最高酯化率99．47％。     

甲苯-4-磺酸催化高效合成尼泊金正丁酯防腐剂

以对羟基苯甲酸和正丁醇为主要原料,甲苯-4-磺酸为催化剂,正丁醇为带水剂,催化合成尼泊金正丁酯。考察了原料对羟基苯甲酸和正丁醇的摩尔比、催化剂用量、反应温度和反应时间等对反应的影响。结果表明,适宜的反应条件:以0.02 mol对羟基苯甲酸计,n(正丁醇)∶n(对羟基苯甲酸)=4∶1,m(甲苯-4-磺酸)∶m(对羟基苯甲酸)=0.12∶1,反应温度140℃,反应时间3 h。该条件下,重复实验3次,尼泊金正丁酯收率均达99%以上。     

固体酸催化合成丁二酸二乙酯研究进展

固体酸能够代替硫酸作为酯化催化剂。评述了对甲苯磺酸、强酸性阳离子交换树脂、六水合三氯化铁、氯化亚锡、四水硫酸铈、一水硫酸氢钠、固体超强酸和杂多酸等固体酸催化合成丁二酸二乙酯的方法。认为强酸性阳离子交换树脂、一水硫酸氢钠、固载固体酸、固体超强酸和杂多酸是合成丁二酸二乙酯的良好催化剂。     

2-乙基-1，3-己二醇萃取硼酸的传质系数

单液滴法因其测量结果精确与实验设备简单等优点广泛应用于萃取过程中的传质研究。应用此方法研究了硼酸在2-乙基-1,3-己二醇-甲苯/卤水体系中的传质系数。结果表明：传质系数随着有机相2-乙基-1,3-己二醇浓度、卤水相硼酸浓度及温度的增加而增大。通过双膜传质理论分析,并引入修正的传质系数关联式,将双膜传质模型应用到此萃取体系中,建立了新的针对此体系的传质系数模型。新模型的计算值与实验值的平均相对误差为7.59 %,两者吻合良好,因此,该模型可用于2-乙基-1,3-己二醇-甲苯体系萃取硼酸过程的设计与放大。     

One-pot synthesis of 1,3-thiazolidin-4-one using ammonium persulfate as catalyst

Ammonium persulfate can be used as a homogeneous catalyst for three-component one-pot synthesis of some 1,3-thiazolidin-4-one derivatives from aldehydes, amines and mercaptoacetic acid under solvent-free conditions with good yields. The characterization of products was generally achieved by IR and NMR techniques. Inexpensive catalyst, high yields, simple product isolation and high atom economy are the noteworthy aspects of the protocols.     

过氧酸条件下催化环戊烯氧化制备戊二醛的工艺研究

以环戊烯（CPE）为原料、在甲酸与过氧化氢形成的过氧甲酸体系中,以铌酸为催化剂一步合成戊二醛,考察了反应物配比、催化剂用量、反应温度、反应时间等对反应的影响。在最佳反应条件下,戊二醛的收率达到65％。该方法反应条件温和、高效节能,具有较好的工业化价值。     

磷钨酸催化合成异丁酸丁酯的研究

以磷钨酸作为催化剂,合成了异丁酸丁酯。研究了催化剂用量、醇酸摩尔比、反应温度、反应时间以及带水剂等因素对酯化率的影响。结果表明,其最优化条件为:异丁酸用量为0.1mol情况下,醇酸摩尔比为1.4∶1,催化剂用量为0.5g,带水剂甲苯为4mL,在118～148℃下,搅拌回流反应约60min,酯化率可达94.5%。