A kinetic study of the reaction between terephthalic acid and ethylene oxide in a nonsolvent system

Kinetics of the reaction between terephathalic acid and ethylene oxide, catalysed by triethylamine, was studied in a high-pressure reactor without using solvent. This reaction was carried out at a temperature range of 80–100°C and at a pressure range of 10–15 Kg/cm² beyond the corresponding vapor pressure of ethylene oxide. Effects of temperature, catalyst concentration, mole ratio of ethylene oxide to terephthalic acid, particle size of terephthalic acid, pK value of the tertiary amine and stirrer speed were experimentally investigated on the yield of bis(2-hydroxyethyl) terephthalate and reaction rates. It was found that the bulk reaction of terephthalic acid with ethylene oxide occurred in the liquid phase. Based on experimental results a reaction mechanism to synthesize bis(2-hydroxyethyl) terephthalate from terephthalic acid and ethylene oxide in a nonsolvent system was proposed, and rate constants were obtained with a model based on this proposed reaction mechanism. The activation energy of the reaction was found to be between 3.67–8.28 kcal/mole in the temperature range of 80–95°C.     

Kinetics of the reaction between terephthalic acid and ethylene oxide under high pressure

Kinetics of the reaction between terephthalic acid and ethylene oxide in n-butanol solvent, catalyzed by triethyl amine, was investigated under high pressure. Effect of temperature, catalyst concentration, ethylene oxide to terephthalic acid ratio and stirrer speed was studied on the rate of formation of bis(2-hydroxy-ethyl)terephthalate. It was found that the reaction of terephthalic acid with ethylene oxide occurred in the liquid phase. The experimental data were correlated with a model based on S_N2 reaction mechanism and the activation energy of the reaction was found to be between 19.3–21.6 kcal/mole in the temperature range of 60–100°C.     

A kinetic study of the reaction between terephthalic acid and ethylene oxide at atmospheric pressure

The kinetics of the reaction of terephthalic acid with ethylene oxide, in n-butanol solvent, catalysed by triethyl amine, were investigated in a semi-batch reactor under atmospheric conditions. It was found that the reaction occurred in the liquid phase and that mass transfer effects were absent. The reaction was found to be pseudo-zero order in terephthalic acid and first order in ethylene oxide and in catalyst concentration. The effects of reaction temperature, catalyst concentration, particle size of terephthalic acid, ethylene oxide flow rate, stirrer speed and terephthalic acid to ethylene oxide ratio were studied. Particle size of terephthalic acid, stirrer speed and flow rate of ethylene oxide did not affect the reaction rate. The Arrhenius activation energy of the reaction was found to be between 19.2 and 23.5 kcal/mol.     

Optimization of the enzymatic production of isoamyl acetate with novozym 435 from candida antarctica

In this study the production of isoamyl acetate by esterification of isoamyl alcohol and acetic acid was carried out using immobilized C . antarctica lipase (Novozym 435) as a catalyst without any organic solvent. The esterification yield was optimized with response surface methodology. This method was used with four parameters to evaluate the effects of important variables on the esterification yield. The parameters are acid/alcohol mole ratio (0.2-0.8), enzyme amount (4-12%, w/w), temperature (30-50 °C), and reaction time (4-8 hr). It was found that the most effective parameter was acid/alcohol mole ratio. As acid/alcohol mole ratio increased at any given reaction time and amount of enzyme, ester concentration, C p (mmol ester/g mixture), increased up to an acid/alcohol mole ratio of 0.7 and thereafter decreased. The model indicated the optimum conditions for maximum esterification (3.45 mmol ester/g mixture) in the acid/alcohol mole ratio of 0.52 for 8.15% enzyme at 43.2 °C and after 5.27 hr, which were in good agreement with the experimental value (3.5 mmol ester/g mixture).     

A kinetic study of the reaction between terephthalic acid and ethylene oxide at atmospheric pressure

The kinetics of the reaction of terephthalic acid with ethylene oxide, in n-butanol solvent, catalysed by triethyl amine, were investigated in a semi-batch reactor under atmospheric conditions. It was found that the reaction occurred in the liquid phase and that mass transfer effects were absent. The reaction was found to be pseudo-zero order in terephthalic acid and first order in ethylene oxide and in catalyst concentration. The effects of reaction temperature, catalyst concentration, particle size of terephthalic acid, ethylene oxide flow rate, stirrer speed and terephthalic acid to ethylene oxide ratio were studied. Particle size of terephthalic acid, stirrer speed and flow rate of ethylene oxide did not affect the reaction rate. The Arrhenius activation energy of the reaction was found to be between 19.2 and 23.5 kcal/mol.     

微波辐射对甲苯磺酸催化合成氯乙酸异辛酯

在微波辐射下,以对甲苯磺酸为催化剂合成氯乙酸异辛酯。考察微波输出功率、反应时间、催化剂用量、酸醇的物质的量比等因素对反应的影响。通过实验得出合成氯乙酸异辛酯的最佳反应条件是:氯乙酸和异辛醇的物质的量比为1:2.0,催化剂用量为2.0g,微波输出功率为522W,反应时间为20min。在此反应条件下,氯乙酸的酯化率为97.6%。     

硫酸氢钾催化合成肉桂酸甲酯

采用微波辐射技术，以自制硫酸氢钾为催化剂，由肉桂酸和甲醇直接酯化合成肉桂酸甲酯。用正交试验研究了各反应因素对产品收率的影响，确定其最佳反应条件为：酸醇摩尔比为1：5，催化剂用量为1．0g，微波功率为729W，辐射时间为5min，产品收率为97．3％，催化剂可重复使用。     

酸掺杂聚苯胺催化马来酸丁酯化及动力学

用对甲苯磺酸作为搀杂剂对水相氧化法合成的盐酸搀杂的聚苯胺(HC l/PANI)进行搀杂,制备了由聚苯胺(PANI)负载对甲苯磺酸的固体酸催化剂(PTSA/PANI)。以PTSA/PANI为催化剂、马来酸酐和正丁醇为原料合成马来酸二丁酯。考察了原料配比、催化剂用量和反应时间等因素对反应的影响以及催化剂的重复使用性能,测定了反应动力学。最佳反应工艺条件为:n(正丁醇)∶n(马来酸酐)=3.33∶1、w(PTSA/PANI)=3.81%、反应温度≤130℃、反应时间3 h。结果表明,在该条件下马来酸酐的转化率为96.23%;催化剂经重复使用5次后,马来酸酐的转化率为90.82%;确定反应级数为二级,表观活化能为41.0 kJ/mol。对甲苯磺酸搀杂聚苯胺催化剂具有催化活性高、稳定性好、容易制备、无环境污染等优点。     

酯化法合成对苯二甲酸二(β-羟乙基酯)的研究

以对苯二甲酸和乙二醇为原料,采用自制催化剂合成出了对苯二甲酸二(β-羟乙基酯)(BHET).最佳反应条件:1 mol对苯二甲酸使用0.2 g催化剂,醇酸摩尔比为12∶1,反应时间为10h,反应温度为185℃.粗品经结晶、重结晶可得质量分数＞99％的BHET产品.     

马来酸双十八酯的合成及宏观动力学

以对甲苯磺酸为催化剂、甲苯为带水剂,以马来酸酐和十八醇为原料合成马来酸双十八酯。考察了原料配比、催化剂用量、带水剂用量和反应时间等因素对反应过程的影响,并测定了动力学数据。通过实验得到了反应工艺条件：n（十八醇）：n（马来酸酐）=2.3：1,对甲苯磺酸用量为马来酸酐和十八醇总质量的0．5％,甲苯用量为马来酸酐和十八醇总质量的96％,反应温度≤130℃、反应时间为4．0h,在该条件下马来酸酐的转化率达到98．76％。合成马来酸单十八酯的反应为二级反应,速率方程中的指前因子为O．655152L／（mol·min）,活化能为17．82kJ／mol。合成马来酸双十八酯的反应为二级反应,速率方程中的指前因子为1．53951×1011L／（mol·min）,活化能为98．05kJ／mol。     

磷钨酸铝催化合成十二烷基磷酸单酯

以磷钨酸铝盐为催化剂,十二醇和磷酸为原料,采用酯化法合成十二烷基磷酸单酯,考察了醇酸物质的量比、带水剂用量、催化剂用量和反应时间对十二醇转化率的影响。采用正交试验法确定了最佳工艺条件：醇酸物质的量比0.04∶0.05, 带水剂甲苯用量0.075 mol,磷钨酸铝0.2 g(反应物总质量的1%),反应温度为回流温度,酯化反应时间1.5 h。在此条件下,醇转化率99.8%,酸转化率82.0%,单酯选择性99.5%。     

微波辐射下NKC-9树脂催化合成1-萘乙酸甲酯

以NKC-9阳离子交换树脂为催化剂,在微波条件下用1-萘乙酸和甲醇合成1-萘乙酸甲酯.最佳合成条件为:醇酸摩尔比为14:1,催化剂为1-萘乙酸的80%,微波辐射时间为15分钟,微波功率为600瓦,产率为80.48%.     

双季戊四醇五丙烯酸酯的合成及表征

利用双季戊四醇与丙烯酸直接酯化合成了双季戊四醇五丙烯酸酯,讨论了阻聚剂、催化剂用量、酸醇物质的量比对产率的影响,利用红外光谱进行了定性分析,得到最佳合成条件是酸醇物质的量比为5.8,催化剂用量为2.5%,阻聚剂为对羟基苯甲醚和TMHPO的复配物。     

酸处理的铌酸催化合成乙基叔丁基醚

用XRD、BET和TG／DTG等考察了水洗铌酸、硝酸处理的铌酸和经硝酸和磷酸处理后的铌酸结构特征和表面酸性。试验研究了用（硝酸＋磷酸）处理的铌酸对制备乙基叔丁基醚（ETBE）催化反应活性的影响,对合成ETBE的醚化反应条件进行了考察。试验结果表明,经硝酸和磷酸处理后的铌酸具有较好的催化合成ETBE的醚化反应性能和稳定性。适宜醚化反应条件为反应温度130℃、乙醇与叔丁醇摩尔比2．0、反应时间3．0h和催化剂用量为原料质量的9．10％。     

杂多酸(盐)催化合成肉桂酸异戊酯的研究

以杂多酸（盐）为催化剂,３Ａ分子筛为脱水剂,肉桂酸和异戊醇为原料合成肉桂酸异戊酯,考察了醇酸比、催化剂种类、催化剂用量、反应时间对酯产率的影响。结果表明,在肉桂酸用量为０１ｍｏｌ情况下,用ＡｌＰＷ１２Ｏ４０为催化剂,催化剂用量为１００ｇ,醇酸摩尔比为２５∶１,反应时间３ｈ,反应温度１３５～１４０℃是最适宜的反应条件。酯产率超过９６％。     

对苯二甲酸回收料改性松香聚酯多元醇的研究

对对苯二甲酸改性松香聚酯多元醇的合成工艺及产品性能进行了研究。重点探索了对苯二甲酸加入量、反应时间、反应温度、催化剂等因素对反应的影响,利用红外光谱及化学分析法对改性松香聚酯多元醇结构进行了表征;结果表明, 在松香105 g,对苯二甲酸45 g,二甘醇150 g,催化剂0.5 g,反应温度250℃,反应时间7h的条件下,松香聚酯多元醇通过对苯二甲酸的改性,产品的酸值≤5 mg/g,羟值380～420 mg/g,黏度5.5～6.5 Pa·s,外观为棕红色,与传统松香聚酯多元醇酯化时间比较,由原来的9 h缩短到7 h;改性松香聚酯多元醇硬泡各项主要质量指标均达到国家标准GB/T 20219-2006。     

微波辐射硫酸氢钠催化合成已酸乙酯的研究

利用微波辐射技术,以硫酸氢钠为催化剂,快速合成了已酸乙酯,并考察了影响反应的因素。实验结果表明:微波辐射功率560 W;辐射时间8 m in;醇酸物质的量比2∶1;硫酸氢钠1.0 g(已酸0.2 mol);酯化率可达96.2%。     

催化合成氯乙酸乙酯

以稀土固体超强酸SO2-4/TiO2/La3+为催化剂,氯乙酸与乙醇为原料合成氯乙酸乙酯。研究了氯乙酸与乙醇的摩尔比、催化剂用量、环己烷的用量、反应时间诸因素对产品收率的影响。结果表明:SO2-4/TiO2/La3+是合成氯乙酸乙酯的良好催化剂,适宜的反应条件如下:氯乙酸与乙醇的摩尔比为1∶3.0,催化剂的用量0.8g,环己烷用量15mL,反应2.0h,氯乙酸乙酯的收率可达92.7%。     

H_3PW_(12)O_(40)/TiO_2催化合成对羟基苯甲酸丁酯的研究

采用溶胶-液相法制备了H3PW12O40/TiO2复合催化剂,用FT-IR分析方法对催化剂进行了结构表征。以对羟基苯甲酸和正丁醇为原料合成了对羟基苯甲酸丁酯,考察了反应物配比、催化剂用量、反应时间及催化剂的重复使用性能对产品收率的影响。实验结果表明,合成对羟基苯甲酸丁酯的较优反应条件为:对羟基苯甲酸0.1 mol,n(对羟基苯甲酸)∶n(正丁醇)=1.0∶5.0(摩尔比),催化剂的用量为1.2 g,反应时间4.0 h。上述条件下,对羟基苯甲酸丁酯的收率可达85.0%以上。     

乙二醇硬脂酸酯的合成

以对氨基苯磺酸为催化剂催化合成乙二醇硬脂酸酯。研究了酯化反应时间、醇酸摩尔比、反应温度、催化剂用量等对产品收率的影响。结果表明,最佳反应条件为:n(醇)∶n(酸)=1.3∶1,催化剂的用量为2.0 g,控温135℃,反应时间为3 h,酯收率可达92.6%。