乙烷催化直接羰基化合成丙酸的研究

采用一种新型的催化体系CaCl2-K2S2O8-CF3COOH,将乙烷直接羰基化合成丙酸。考察了反应过程中温度、反应时间、CO压力和催化剂等因素对反应收率的影响,找出了反应所需的最优化条件,使丙酸的收率达到86.0％左右。给出了可能的反应机理。     

Batch alcoholic fermentation modelling by simultaneous integration of growth and fermentation equations

The modelling of batch growth and fermentation data presents important disadvantages when numerically calculated specific rates are used. In this paper, the results obtained using a different technique, based on the integration of the differential rate equations in the modelling of batch alcoholic fermentation with Saccharomyces cerevisiae at different temperatures and initial sugar concentrations, are presented, and the use of both techniques is discussed.     

间歇精馏模拟及操作方式的研究进展

综述了间歇精馏模拟研究常用的数学模型,主要介绍了严格模型和简捷模型,简要讨论了各个模型的特点.较详细地介绍了国内外间歇精馏操作方式的研究进展,讨论了动态累积间歇精馏塔、反向间歇精馏塔、中间罐间歇精馏塔、多罐间歇精馏塔等新塔型的操作.     

相转移催化合成对氟苯氧丙酸

采用对氟苯酚和3-氯丙酸为起始原料,用聚乙二醇PEG-400和KI双组分催化剂合成对氟苯氧丙酸。本文探讨了原料配比、反应时间和催化剂对产物收率的影响,找到了较佳的合成条件。     

Novel repeated batch operation for flash fermentation system: Experimental data and mathematical modelling

A novel repeated batch operation mode was proposed for ethanol fermentation, where the fermenter beer was periodically exchanged between the fermenter with biomass recycle and the distillation unit, to promote the selective removal of ethanol. Using the mathematical model developed, as based on the experimental results, the optimal operation of the proposed method was shown to attain high performance, with a productivity of about 12 g dm⁻³ h⁻¹ and a product concentration of 400 g dm⁻³.     

Mathematical modelling of the alcoholic fermentation of glucose by Zymomonas mobilis mobilis

The kinetics of alcoholic fermentation of a strain of Zymomonas mobilis, isolated from sugarcane juice, has been studied with the objective of determining the constansts of a non-structured mathematical model that represents the fermentation process. Assays in batch and in continuous culture have been carried out with different initial concentrations of glucose. The final concentrations of glucose, ethanol and biomass were determined. The following kinetic parameters were obtained: μ_max, 0·5 h^?1; K_s, 4·64 g dm^?3; P_max, 106 g dm^?3; Y_x/s, 0·0265 g g^?1; m, 1·4 g g^?1 h^?1; α, 17·38 g g^?1; β, 0·69 g g^?1 h^?1.     

气相催化丙酸与甲醛缩合反应制甲基丙烯酸

采用等体积浸渍法制备一系列Cs负载催化剂,采用XRD、ICP和物理吸附等对催化剂进行表征。在固定床反应器中进行气相催化丙酸与甲醛羟醛缩合反应制备甲基丙烯酸,以多聚甲醛解聚液为甲醛源头,考察载体种类、Cs负载量、铯源、反应温度及载气流速等对催化剂催化性能的影响。结果表明,较优的工艺条件为:反应温度340℃,活性组分Cs负载质量分数10%,丙酸与甲醛物质的量比1∶2,载气N2流速60 mL·min^(-1),此条件下,催化剂具有较好的催化活性,甲基丙烯酸收率为26%,甲基丙烯酸选择性为90.4%。     

间歇精馏技术及其模拟优化研究进展

间歇精馏技术是一种重要的化工分离手段。文章综述了国内外间歇精馏技术及其常用的数学模型，其中主要阐述了严格模型和简捷模型，简要讨论了降价模型、半严格模型，同时探讨了间歇精馏优化的发展及其应用，并展望了间歇精馏系统的发展趋势。     

羰基合成丙酸铱催化剂的研究

结合均相催化甲醇羰基化合成醋酸的工业化路线,制备羰基合成丙酸铱催化剂。研究发现,通过添加助催化剂钌和铟,铱催化羰基合成丙酸的反应活性进一步提高,且稳定性较好;腐蚀金属对铱催化剂的活性和稳定性均有不利影响;添加少量碘化锂对铱催化羰基合成丙酸的反应活性基本无影响,对稳定性略有提升。优选反应组成发现,在高丙酸乙酯含量条件下,催化羰基化活性较优,添加钌、铟和碘化锂的铱催化体系的时空产率超过3.0 mol·(L·h)-1。阐述了铱催化羰基合成丙酸的可能反应机理,并对羰基合成丙酸的工艺路线进行技术经济性评价。     

Batch production of L(+) lactic acid from whey by Lactobacillus casei (NRRL B‐441)

The effects of temperature, pH, and medium composition on lactic acid production by Lactobacillus casei were investigated. The highest lactic acid productivity values were obtained at 37 °C and pH 5.5. The productivity was 1.87 g dm^?3 h^?1 at 37 °C in shake flasks. In the fermenter, a productivity of 3.97 g dm^?3 h^?1 was obtained at pH 5.5. The most appropriate yeast extract concentration was 5.0 g dm^?3. Whey yielded a higher productivity value than the analytical lactose and glucose. Initial whey lactose concentration did not affect lactic acid productivity. MnSO₄ ·H₂O was necessary for lactic acid production by L casei from whey. Product yields were approximately 0.93 g lactic acid g lactose^?1. Copyright © 2004 Society of Chemical Industry     

Mathematical model of growth and polyhydroxybutyrate production using microbial fermentation of Bacillus subtilis

Poly-3-hydroxybutyrate (PHB) has been extensively utilized as a biodegradable plastic. The value of substrate inhibition constant (K_I) was also established in shake flask cultures by varying the initial glucose concentration (20–160?g/L) in growth media. Excess carbon source adversely affected the growth of Bacillus subtilis cultures. The production kinetics of PHB was studied using batch fermentation strategy for B. subtilis culture. Batch cultivation was also performed in a 5-L stirred tank bioreactor to obtain a Biomass and PHB yield of 5.25 and 1.6?g/L, respectively. The kinetic data of biomass, PHB production, and substrate consumption was used to estimate the optimized values of the growth and product formation kinetic parameters. Optimal values of kinetic parameters (µ_m value of 0.325, K_S value of 10.53?g/L for glucose, Y value of 0.183?g/g of glucose, K_I value of 105?g/L, m value of 0.12?g/(g h), k₁ of 0.36?g/g, and k₂ value was 0.12?g/(g h)) and the initial values of biomass, substrate and PHB concentration (X?=?0.14?g/L, S?=?9.99?g/L, and P?=?0.13?g/L) were utilized to obtain a modified mathematical model for PHB production. Statistical validity of the mathematical model simulations were measured using F-test. The F-test showed that the statistical validity of the model was more than 95% when compared with experimentally obtained values. This model also predicted that the production of PHB using B. subtilis cultures is mainly growth associated.     

乙醇羰基化制丙酸及丙酸乙酯多相催化剂研究进展

丙酸及丙酸乙酯是重要的化工产品和有机合成中间体。由于中国乙醇资源丰富,因此以乙醇为原料的非石油途径合成丙酸及丙酸乙酯得到广泛研究。乙醇均相羰基化存在收率低、反应条件苛刻以及产物与催化剂分离困难等问题。目前,多数研究主要集中在乙醇羰基化多相催化剂的开发。乙醇羰基化多相催化剂分为两类：贵金属催化剂和非贵金属催化剂。详细介绍了两类催化剂的研究进展,重点阐述了两类催化剂的反应机理以及助剂、载体和工艺参数对催化剂性能的影响,指出了不同催化剂的优势和不足,并对催化剂应用现状进行了分析。最后展望了乙醇多相羰基化合成丙酸及丙酸乙酯的发展前景,以期为设计和研发具有高活性和稳定性的催化剂提供思路。     

乙醇羰基化制丙酸及丙酸乙酯多相催化剂研究进展

丙酸及丙酸乙酯是重要的化工产品和有机合成中间体。中国乙醇资源丰富，以乙醇为原料的非石油途径合成丙酸及丙酸乙酯得到了广泛研究。乙醇均相羰基化存在收率低、反应条件苛刻以及产物与催化剂分离困难等问题。目前，多数研究主要集中在乙醇羰基化多相催化剂的开发。乙醇羰基化多相催化剂分为两类：贵金属催化剂和非贵金属催化剂。该文详细介绍了两类催化剂的研究进展，重点阐述了两类催化剂的反应机理以及助剂、载体和工艺参数对催化剂性能的影响，指出了不同催化剂的优势和不足，并对催化剂应用现状进行了分析。最后展望了乙醇多相羰基化合成丙酸及丙酸乙酯的发展前景。     

基于非结构模型的纳他霉素分批发酵动力学及调控策略

建立了褐黄孢链霉菌分批发酵生产纳他霉素过程基于非结构模理的菌体生长、基质消耗和产物形成的动力学方程。模型验证实验数据表明,在0-80h内模型值与实验值拟合良好。据此采取分段控制的调控策略,30L发酵罐中发酵80h纳他霉素产量达4．41g/L,综合考虑发酵周期等因素,文章结果已达较高水平。     

The production of propionic acid from sugars by fermentation through lactic acid as an intermediate

As an alternative to propionic acid production from sugars by species of propionibacteria, propionic acid may be produced from sugars through lactate as an intermediate. Propionibacteria are actually able to utilize lactate as a substrate much more rapidly than glucose. In this study, Lactobacillus xylosus and Propionibacterium shermanii were utilized to convert glucose and xylose to propionate through lactate as an intermediate. Pure culture batch studies were carried out to obtain fermentation parameters for the two cultures. The pure cultures were then combined in a mixed culture series arrangement designed to prevent nutrient limitation. Finally, propionic acid production from lactate was demonstrated in a cross-linked immobilized cell reactor using lactate added to the medium and produced by L. xylosus in a continuous stirred tank reactor. Productivities of 14 g dm^?3 h^?1 at a 9 min residence time (2·1 g dm^?3 propionate) and 2 g dm^?3 h^?1 at a 9·9 h residence time (19·7 g dm^?3 propionate) were obtained without pH control.     

Batch and Continuous Production of Lactic Acid from Beet Molasses by Lactobacillus delbrueckii IFO 3202

Process variables were optimized for the production of lactic acid from pretreated beet molasses by Lactobacillus delbrueckii IFO 3202 for batch and continuous fermentations. In the batch fermentation, maximum yields (95·4% conversion, 77·1% effective) and maximum lactic acid volumetric productivity (4·83 g dm⁻³ h⁻¹) was achieved at 45°C, pH 6·0, 78·2 g dm⁻³ sugar concentration with 10 g dm⁻³ yeast extract. Various cheaper nitrogen sources were replaced with yeast extract on equal nitrogen bases in batch fermentation. Of all the nitrogen sources tested, yeast extract yielded the highest and malt sprouts yielded the second highest level of lactic acid. In the continuous fermentation, maximum lactic acid (4·15%) was obtained at a dilution rate of 0·1 h⁻¹. Maximum volumetric lactic acid productivity (11·20 g dm⁻³ h⁻¹) occurred at D = 0·5 h⁻¹ dilution rate. © 1997 SCI.     

基于pH控制的丙酮丁醇间歇发酵过程动力学模型

基于微生物发酵动力学模型和丙酮丁醇发酵工艺的特点,由5组控制pH下的实验数据建立该发酵过程的动力学模型,采用改进的自适应遗传算法对模型的12个参数进行优化,并采用一组控制pH数据对模型进行了外推验证,结果表明,该模型能够较好地描述pH的丙酮丁醇间歇发酵过程.     

Strategies of pH control and glucose‐fed batch fermentation for production of succinic acid by Actinobacillus succinogenes CGMCC1593

BACKGROUND: Succinic acid is an important precursor of numerous products, including pharmaceuticals, feed additives, green solvents, and biodegradable polymers. In this work, strategies of pH control and glucose‐fed batch fermentation for producing succinic acid using Actinobacillus succinogenes CGMCC1593 were carefully optimized. RESULTS: The production of succinic acid was stable within the pH range 6.0–7.2. Both cell growth and succinic acid production were inhibited by high concentrations of sodium and calcium ions, while there was no significant inhibition by magnesium ions. With an initial glucose concentration of 25 g L^?1, and glucose concentration was maintained between 10 and 15 g L^?1 during the course of fed batch fermentation, succinic acid concentration, productivity and yield were 60.2 g L^?1, 1.3 g L^?1 h^?1 and 75.1%, respectively. CONCLUSION: Of all the neutralization reagents used for pH control of A. succinogenes CGMCC1593, solid MgCO₃ was the most satisfactory. With increase of initial glucose concentration, the time course showed a longer growth lag period and the maximum biomass declined, while more carbon was diverted to succinate synthesis. The results obtained in this study should be helpful for the design of a highly efficient succinic acid production process. Copyright © 2008 Society of Chemical Industry     

二羟甲基丙酸的合成研究

合成了二羟甲基丙酸,对合成产品进行了表征及合成条件的探讨。