丙酮氨氧化制备丙酮肟过程中副反应研究

通过GC-MS、LC-MS等方法表征TS-1催化丙酮氨氧化制备丙酮肟过程中的副产物结构,分析副反应类型。结果表明:在此反应体系中,副反应主要产生途径有:(1)碱催化酮缩合,导致副产物骨架的生成;(2)亲核氨解,生成各种有机胺,导致体系碱性增强,起到自催化的作用;(3)消除脱水生成烯烃,然后烯烃被H2O2环氧化;(4)酮类副产物肟化;(5)酮肟氧化偶联反应生成2,3-二硝基-2,3-二甲基丁烷(DMNB);(6)其它氧化过程生成不饱和度高的副产物等。     

浅谈化工原理精品课程建设的探索与实践

文章在化工原理精品课程建设实践的基础上,讨论了精品课程建设的几个重要方面,从建设精品课堂开始,编制适合教学实际的精品教材,开发创新性实验,提高人才培养效率。精品课程建设对深化教学改革、进一步提高教学质量将起到很好的示范和指导作用。     

沥青质热裂解、临氢热裂解和临氢催化裂解反应动力学

 实验考察了1种正戊烷不溶解的沥青质在703 K下的热裂解、临氢热裂解和由 NiMo/γ-Al₂O₃催化的临氢裂解反应。3种沥青质转化反应都能较好地吻合二级反应动力学,得到的表观速率常数分别为1.704×10^-2、 2.435×10^-2和9.360×10^-2。建立三集总动力学模型,用于求解沥青质裂解转化生成液体油反应速率常数(k₁)和与之平行的生成焦炭＋气体反应速率常数（k₃）,以及由液体产物继续转化生成焦炭＋气体的反应速率常数（k₂）。对沥青质热裂解、临氢热裂解和临氢催化裂解反应,速率常数 k₁分别为1.697×10^-2、 2.430×10^-2和9.355×10^-2, k₂分别为3.605×10^-2、 2.426×10^-2和6.347×10^-3, k₃分别为6.934×10^-5、 5.416×10^-5和4.803×10^-5。     

1-己烯热裂解反应动力学分析

在873~973 K温度区间,用柱塞流连续流动管式反应器考察1-己烯热裂解反应。根据反应产物的种类分布并结合自由基基元反应化学,建立1-己烯热裂解链式反应机理模型,推导出相应的反应动力学方程。通过拟合反应实验数据,证实1-己烯热裂解转化具有一级反应动力学的特征,反应温度从873 K依次升高到923 K和973 K,反应速率常数从0.0312 s-1提高到0.116 s-1和0.453 s-1。在所观察的温度区间,该反应的表观活化能为（188.7±1.0）kJ/mol。     

水蒸气抑制2-甲基戊烷在USHY上催化裂解反应中焦炭生成

The effect of steam dilution on the formation of coke and minor products in 2-methylpenatne cracking on ultra stable HY at 673 K has been studied. The results show that steam dilution suppresses the formation of coke and minor aromatic products, but enhances the H/C atomic ratio of coke and the production of di-olefins. This and other evidences suggest that steam dilution enhances the desorption of coke precursors, diolefinic ions and cyclic ions, by inhibiting the further pathological reactions to produce aromatics and polyaromatics. These insights into the chemistry underlying coke formation in hydrocarbon cracking on solid acid catalysts can potentially be applied to the development of additives which inhibit coke formation and control catalyst deactivation.     

正己烷热裂解链式反应机理和选择性分析

 采用柱塞流连续流动管式反应器考察了正己烷在923 K下的热裂解反应。结果表明,主要产物包括C2~C4烷烃、C2~C5烯烃、 异己烷、焦炭和H2。根据产物种类和选择性分布,建立了正己烷热裂解的自由基链式反应机理模型,并对所含各基元反应的选择性进行了定量分析。     

间歇色谱与模拟移动床色谱分离奥美拉唑对映体的比较

用纤维素三苯基氨基甲酸酯涂敷型手性固定相和含0.1%二乙胺的乙醇溶液,研究了模拟移动床色谱和间歇色谱对奥美拉唑对映体的拆分.其中,间歇色谱分离过程采用基于线性推动力模型的动力学模型研究,优化出生产能力最大的操作条件.以生产能力、溶剂消耗和回收率三个指标比较了这两种色谱操作模式.结果表明:模拟移动床色谱分离效果优于间歇色谱,生产能力为间歇色谱的5倍以上,回收率则高出1.28倍以上,溶剂消耗则可节省约22%,     

溶剂萃取恢复渣油加氢转化催化剂活性的研究

催化加氢处理是渣油裂化加工的重要技术，但焦炭和金属在催化剂上的沉积将降低催化剂的活性。采用溶剂萃取法除去工业失活催化剂上沉积的焦炭和金属的研究结果表明，用四氢呋喃、吡啶和喹啉这3种含杂原子的有机强溶剂常温萃取催化剂，其去除焦炭能力很弱，而且会因这些溶剂的强吸附作用污染催化剂；盐酸洗涤能有效去除催化剂表面的钙、铁沉积层，但不能去除焦炭；低芳香性的加氢瓦斯油在400 C、H2压力为10MPa、反应1h的条件下可部分去除催化剂上的焦炭，但不具备强的氢化焦炭作用；1,2,3,4-四氢化萘因具有供给原子氢的能力，可以有效地氢化和去除催化剂上的焦炭。一旦除去一定量的焦炭或金属化合物沉积物，失活催化剂的加氢脱硫活性将得到恢复。     

沥青质加氢热裂解和催化加氢裂解反应动力学与选择性

A pentane-insoluble mixture of asphaltenes was processed by thermal hydrocracking and catalytic hydrocracking over Ni-Mo/γ-Al2O3 catalyst in a microbatch reactor at 430 ℃.The experimental data of asphaltene conversion adequately fit second-order kinetics to give the apparent rate constants of 2.435×10-2 and 9.360×10-2 (wt frac)-1 min-1 for the two processes,respectively.A three-lump kinetic model is proposed to evaluate the rate constants for parallel reactions of asphaltenes producing liquid oil (k1) and gas+coke (k3),and consecutive reaction producing gas+coke (k2) from this liquid oil.The evaluated constants for asphaltenes hydrocracking,in the presence and absence of the catalyst,respectively,show that k1 is 2.430×10-2 and 9.355×10-2 (wt frac)-1 min-1,k2 is 2.426×10-2 and 6.347×10-3 min-1,and k3 is 5.416×10-5 and 4.803×10-5 (wt frac)-1 min-1.As compared with the thermal hydrocracking of asphaltenes,the catalytic hydrocracking of asphaltenes promotes liquid production and inhibits coke formation effectively.     

双进料模拟移动床分离α-生育酚(英文)

A two-feed simulated moving bed(SMB) was proposed to utilize the stationary phase more effectively.Zone I is disconnected with zone II and zone III is disconnected with zone IV.Two feeds are added to zones I and III,while two desorbents are added to zones II and IV separately.The investigation on the movement of concentra-tion bands indicated that the tail of the strong retained solute and the front of the weak retained solute were eluted from zones I and III orderly,so the streams from zones I and III could be cut into different fractions to give the products with high purity.The two-feed SMB was used to separate α-tocopherol from its homologue mixture suc-cessfully,and could double the productivity if both feeds were identical to the feed in the conventional four-zone SMB.The solvent consumption could be reduced by reusing the middle fraction without solutes.