以强酸型阳离子交换树脂为催化剂,甲醇、稀甲醛为原料在间歇反应釜中合成甲缩醛(二甲氧基甲烷)。实验中,各组分的测定采用校正面积归一化法与亚硫酸钠分析法相结合的方式。通过实验,考察了催化剂用量与不同温度对甲醛反应速率的影响,测...以强酸型阳离子交换树脂为催化剂,甲醇、稀甲醛为原料在间歇反应釜中合成甲缩醛(二甲氧基甲烷)。实验中,各组分的测定采用校正面积归一化法与亚硫酸钠分析法相结合的方式。通过实验,考察了催化剂用量与不同温度对甲醛反应速率的影响,测定了反应平衡常数。文章采用拟均相模型对实验数据进行拟合,考察了313,318,323,328 K 4个温度下的正逆反应速率。实验结果表明:催化剂A的最佳用量为总溶液质量分数的3%;采用拟均相模型对实验线性拟合,线性关系显著,验证了假设的反应机理,并回归得到了在313—328 K下的指前因子k0、活化能Ea及宏观动力学方程,反应表现级数为二级。通过对实验与计算值的比较验证,此宏观动力学方程合理,可用于模拟计算。展开更多
The present work contributed to a new developed production method for enhancing the quality of isoamylene （IA） by adding a small amount of tertiary amyl alcohol （TAA） to the catalyst of strong acid cation exchange...The present work contributed to a new developed production method for enhancing the quality of isoamylene （IA） by adding a small amount of tertiary amyl alcohol （TAA） to the catalyst of strong acid cation exchange resin. TAA improved the selectivity of 2-methyl-2-butene （2M2B） at a high conversion level for the isomerization of IA. Compared with the other results from the current IA units, the conversion of 2-methyl- 1-butene （2M1B）, the mass ratio of 2M2B to 2M1B and the selectivity of 2M2B were increased from 0.5474, 7.32 and 0.6864 to 0.72, 12 and 0.95, respectively, while the dimers content in the products decreased from 4.38% to below 1.0%. Optimized conditions for IA isomerization consisted of temperature between 28 and 33℃ and system pressure of 0.5 MPa, weight hourly space velocity of 8.0 h-1 with TAA mass fraction of 0.7%-0.9% in raw material. The results in lab supported bases for the developed process in industrial application which was later proved to be successful. In addition, a possible mechanism of the isomerization process was speculated to propose a key step of water formation in the TAA-added isomerization process and a verified experiment was conducted to support this speculation.展开更多
A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization （in moderate conditions：200 ＆#176;C, 12 h） of red liquor solids, a by-product of paper-making process. The prepared sulfonate...A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization （in moderate conditions：200 ＆#176;C, 12 h） of red liquor solids, a by-product of paper-making process. The prepared sulfonated cata-lyst （SC） had aromatic structure, composed of carbon enriched inner core, and oxygen-containing （SO3H, COOH, OH） groups enriched surface. The SO3H, COOH, OH groups amounted to 0.74 mmol·g^-1, 0.78 mmol·g^-1, 2.18 mmol·g^-1, respectively. The fresh SC showed much higher catalytic activity than that of the traditional solid acid catalysts （strong^-acid 732 cation exchange resin, hydrogen type zeolite socony mobile-five （HZSM-5）, sulfated zir-conia） in esterification of oleic acid. SC was deactivated during the reactions, through the mechanisms of leaching of sulfonated species and formation of sulfonate esters. Two regeneration methods were developed, and the catalytic activity can be mostly regenerated by regeneration Method 1 and be fully regenerated by regeneration Method 2, respectively.展开更多
The cost of raw materials has the largest contribution to the final price of biodiesel produced by traditional routes, currently adopted in most industrial scale processes. That contribution comes from the need to use...The cost of raw materials has the largest contribution to the final price of biodiesel produced by traditional routes, currently adopted in most industrial scale processes. That contribution comes from the need to use edible and noble oils, with low acidity, such as soybean oil. This work proposes＇the use of Macauba oil, a vegetable oil in focus in the State of Minas Gerais, Brazil, in which the current extractive yield generates a raw material with high acidity, therefore, not suitable to be used in biodiesel production. To make it technically feasible, a cationic exchange resin, the Purolite CT275DR, was used as a catalyst for esterification reaction with samples of Macauba oil, aiming to reduce its acidity. The resin can be reused, regenerated and easily removed from the reaction product, reducing costs with catalyst and purification stages. As a result of this work, in a sample of oil with an initial acidity of about 10% m/m were achieved acidity reductions up to 97% by using cationic resins as catalyst, demonstrating its potential use in the oil pretreatrnent step. Additionally, the data collected during all the analysis made it possible to define the chemical kinetic of the esterification reaction.展开更多
文摘以强酸型阳离子交换树脂为催化剂,甲醇、稀甲醛为原料在间歇反应釜中合成甲缩醛(二甲氧基甲烷)。实验中,各组分的测定采用校正面积归一化法与亚硫酸钠分析法相结合的方式。通过实验,考察了催化剂用量与不同温度对甲醛反应速率的影响,测定了反应平衡常数。文章采用拟均相模型对实验数据进行拟合,考察了313,318,323,328 K 4个温度下的正逆反应速率。实验结果表明:催化剂A的最佳用量为总溶液质量分数的3%;采用拟均相模型对实验线性拟合,线性关系显著,验证了假设的反应机理,并回归得到了在313—328 K下的指前因子k0、活化能Ea及宏观动力学方程,反应表现级数为二级。通过对实验与计算值的比较验证,此宏观动力学方程合理,可用于模拟计算。
文摘The present work contributed to a new developed production method for enhancing the quality of isoamylene （IA） by adding a small amount of tertiary amyl alcohol （TAA） to the catalyst of strong acid cation exchange resin. TAA improved the selectivity of 2-methyl-2-butene （2M2B） at a high conversion level for the isomerization of IA. Compared with the other results from the current IA units, the conversion of 2-methyl- 1-butene （2M1B）, the mass ratio of 2M2B to 2M1B and the selectivity of 2M2B were increased from 0.5474, 7.32 and 0.6864 to 0.72, 12 and 0.95, respectively, while the dimers content in the products decreased from 4.38% to below 1.0%. Optimized conditions for IA isomerization consisted of temperature between 28 and 33℃ and system pressure of 0.5 MPa, weight hourly space velocity of 8.0 h-1 with TAA mass fraction of 0.7%-0.9% in raw material. The results in lab supported bases for the developed process in industrial application which was later proved to be successful. In addition, a possible mechanism of the isomerization process was speculated to propose a key step of water formation in the TAA-added isomerization process and a verified experiment was conducted to support this speculation.
基金Supported by the State Key Development Program for Basic Research of China(2013CB228104,2010CB732205)Ph.D Programs Foundation of Ministry of Education of China(20120172110011)the National High Technology Research and Development Program of China(2012AA051801)
文摘A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization （in moderate conditions：200 ＆#176;C, 12 h） of red liquor solids, a by-product of paper-making process. The prepared sulfonated cata-lyst （SC） had aromatic structure, composed of carbon enriched inner core, and oxygen-containing （SO3H, COOH, OH） groups enriched surface. The SO3H, COOH, OH groups amounted to 0.74 mmol·g^-1, 0.78 mmol·g^-1, 2.18 mmol·g^-1, respectively. The fresh SC showed much higher catalytic activity than that of the traditional solid acid catalysts （strong^-acid 732 cation exchange resin, hydrogen type zeolite socony mobile-five （HZSM-5）, sulfated zir-conia） in esterification of oleic acid. SC was deactivated during the reactions, through the mechanisms of leaching of sulfonated species and formation of sulfonate esters. Two regeneration methods were developed, and the catalytic activity can be mostly regenerated by regeneration Method 1 and be fully regenerated by regeneration Method 2, respectively.
文摘The cost of raw materials has the largest contribution to the final price of biodiesel produced by traditional routes, currently adopted in most industrial scale processes. That contribution comes from the need to use edible and noble oils, with low acidity, such as soybean oil. This work proposes＇the use of Macauba oil, a vegetable oil in focus in the State of Minas Gerais, Brazil, in which the current extractive yield generates a raw material with high acidity, therefore, not suitable to be used in biodiesel production. To make it technically feasible, a cationic exchange resin, the Purolite CT275DR, was used as a catalyst for esterification reaction with samples of Macauba oil, aiming to reduce its acidity. The resin can be reused, regenerated and easily removed from the reaction product, reducing costs with catalyst and purification stages. As a result of this work, in a sample of oil with an initial acidity of about 10% m/m were achieved acidity reductions up to 97% by using cationic resins as catalyst, demonstrating its potential use in the oil pretreatrnent step. Additionally, the data collected during all the analysis made it possible to define the chemical kinetic of the esterification reaction.
