环路反应器制备聚甘油的研究

以工业甘油和自制催化剂为原料在环路反应器上制备聚甘油,通过监测反应过程中游离甘油含量和羟值的变化以确定甘油转化率和产物的平均聚合度。研究了反应温度、催化剂用量和反应器压力对甘油转化率及产品平均聚合度的影响。结果表明,环路反应器制备聚甘油的优化工艺条件为:反应温度240℃,催化剂用量2.0%,反应器压力0.2~0.3 MPa;此条件下甘油转化率可以达到99%以上,产品的平均聚合度能达到20以上。     

浅析碳三加氢反应器中丙烯损失的原因及优化对策

通过分析碳三加氢反应器运行中存在的问题,重新调整了操作变量,优化了进料条件,减少了丙烯在碳三加氢反应器中的损失.     

碳二加氢直列式三段反应器的长周期运行

国内部分乙烯装置的反应器为直列式三段反应器,这种布局方式的优点是物料流向和操作简单,但缺点是反应器的切换和再生是3个反应器同时进行,在反应器切换过程中,易发生漏炔和飞温,再生时由于温度从下到上逐渐降低,很难使催化剂再生完全,因此,保证催化剂的长周期运行至关重要。通过对碳二加氢直列式三段反应器负荷的优化分配,合理设定各段的氢与炔体积比,使反应器由原来平均运行6个月,提升到运行13个月以上,满足了装置长周期运行的要求。     

20%中/长链脂肪乳注射液制备工艺研究

研究20%中/长链脂肪乳注射液的制备工艺,对水相p H、油相水相混合温度及混合时间、均质条件、灭菌条件进行筛选。结果表明,最佳工艺为:水相p H为9.5~10.5,在50~70℃下将油相水相高速混合15~20 min;在60 MPa下进行高压均质6次,均质温度维持在45~50℃;于121℃灭菌12 min。该工艺重现性好,可以用于规模化生产。     

含长碳链富勒烯衍生物的制备与表征

为了改善有机太阳能电池的光电特性,本文设计一种溶解性良好的富勒烯衍生物作为电池的受体材料。以对苯二酚和溴代正辛烷为原料制备对辛烷氧基苯酚中间体,再与丙二酸环亚异丙酯反应合成丙二酸单酯,进一步与十二醇酯化合成不对称丙二酸双酯,最后与富勒烯(C60)进行Bingel反应制备了含长碳链的富勒烯衍生物目标物,该化合物结构与电化学性质完全被表征。     

搅拌式反应器生物脱硫过程中DBT的传质分析

应用数学模型预测有机相体积含量较大时油-水双液相体系中液滴的直径,进一步推导出二苯并噻吩(DBT)从有机相主体到两相界面的传质速率,从而考察不同有机相组成、有机相体积分率、不同温度、水相组成以及搅拌速率等对传质速率的影响,确定了搅拌速率是影响传质速率的决定性因素;通过对理论传质速率与生物脱硫速率的比较,进一步研究生物脱...     

基于鲁棒模型优化的工艺设计与控制系统集成

采用一种基于鲁棒模型优化方法求解工艺设计与控制集成问题,其核心思想是采用参数不确定状态空间模型描述闭环系统的非线性行为,基于该模型以及二次李雅普诺夫函数可估计系统在外部扰动作用下过程变量变化的最大边界,同时也可测试系统的鲁棒稳定性。该方法避免了求解集成优化问题常用的动态优化方法,可将其转化成一个非线性规划问题。该方法应用于CSTR反应过程的集成优化设计中,结果表明在存在外部扰动时,不仅可以保证过程的经济性能和动态性能,也可保证系统的鲁棒稳定性。     

长碳链聚酰胺弹性体的制备及其低温力学性能

以十二碳二元胺、癸二酸、聚四氢呋喃醚二醇为原料,通过熔融缩聚两步法制备了两种软段含量较高的长碳链聚酰胺弹性体(LCPAE).采用傅里叶变换红外吸收光谱、核磁共振氢谱确认了LCPAE的化学结构,使用凝胶渗透色谱测试了LCPAE的分子量,通过差示扫描量热分析、热重分析探究了LCPAE的热性能,最后采用电子万能试验机、动态力...     

Synthesis of medium-chain glycerides by lipase in organic solvent

Using commercial lipases from various microbial origins, medium-chain glycerides, such as mono-, di-, and tricaprin, were synthesized in isooctane from glycerol and capric acid. The enzyme reaction was performed with 0.35 M capric acid, 0.025 M glycerol, and 0.46 g silica gel to remove water in 5 mL of isooctane with 30 mg lyophilized lipase. Of the 21 kinds of lipases, 11 showed good synthetic activities. Lipases fromPseudomonas aeruginosa (Lipase PS),Rhizomucor miehei lipase andChromobacterium viscosum lipase (Lipase CV) showed high activities for the production of tricaprin, while lipase OF-360 (fromCandida rugosa) and lipase D (Rhizopus delemar) were good for dicaprin production. Lipases CC and MY fromC. rugosa (C. cylindracea) and lipase D (Rhizopus delemar) were good for dicaprin production. Lipases CC and MY fromC. rugosa (C. cylindracea) also showed high activities for dicaprin and tricaprin. Some lipases, especially lipase PS, had high thermal stability over 60°C. The optimal lyophilization pH to dehydrate the lipase coincides with the optimal buffer solution pH for hydrolysis.     

固定化假丝酵母脂肪酶催化合成辛酸甘油酯

以自制固定化假丝酵母脂肪酶作为催化剂,研究了无溶剂体系中辛酸和甘油直接酯化合成辛酸甘油酯的反应条件。考察了酶的种类、底物的物质的量之比、温度、酶量、甘油的初始含水量和反应时间等因素对辛酸转化率和产物组成的影响。结果证明,以纺织物作为载体制备的固定化假丝酵母脂肪酶适宜催化辛酸甘油酯的合成。最优反应条件为：辛酸与甘油的物质的量之比为2∶1,固定化假丝酵母脂肪酶加量为0.5g/0.69g甘油,温度为40 ℃,振荡培养箱转速为190 r/min。最优反应条件下辛酸转化率可以达到94%以上,经过简单处理的固定化酶可以重复使用4批。     

Medium-chain fatty acid-rich glycerides by chemical and lipase-catalyzed polyester-monoester interchange reaction

Medium-chain triglycerides (MCT) that contain caprylic acid (C_8:0) and capric acid (C_10:0) have immense medicinal and nutritional importance. Coconut oil can be used as a starting raw material for the production of MCT. The process, based on the interchange reaction between triglycerides and methyl esters of medium-chain fatty acids by chemical catalyst (sodium methoxide) or lipase (Mucor miehei) catalyst, appears to be technically feasible. Coconut oils with 25–28.3% (w/w) and 22.1–25% (w/w) medium-chain fatty acids have been obtained by chemical and lipase-catalyzed interchange reactions. Coconut olein has also been modified with C_8:0 and C_10:0 fatty acids, individually as well as with their mixtures, by chemical and lipase-catalyzed interchange reactions. Coconut olein is a better raw material than coconut oil for production of mediumchain fatty acid-rich triglyceride products by both chemical and lipase-catalyzed processes.     

合成反应与精馏过程耦合制备四乙酰乙二胺

采用精馏过程与合成反应耦合技术生产四乙酰乙二胺 ,并研究了物料比、反应温度和时间对产率的影响。结果显示最佳工艺条件为 :n(乙二胺 )∶n(乙酸 )∶n(乙酐 ) =1∶2 .5∶6 ,第一步在 1 2 0℃下反应 3h ,第二步在 1 4 0℃下反应 6h。控制合适的精馏回流比 ,总收率可达 79%。     

PVFM的合成工艺及相关化学反应探讨

介绍了一种高效甲醛阻聚剂PVFM的主要生产工艺;简述了这种高效阻聚剂的阻聚原理;通过对调聚反应、酸性水解反应的深入分析,指出工艺中采用了复合引发剂BPO、H2O2,并提出了由BPO引发反应温度上限的设计依据;分析了工艺中各主、副化学反应的机理;阐述了PVFM分子聚合度、分子量、多种调聚基团的工艺控制途径;推测PVFM分子的一种可能结构;提出将有益副反应提升至主反应的工艺设计思路。     

Ammonia removal by air stripping in a semi-batch jet loop reactor

Ammonia is very toxic chemical and it can be removed by air stripping at high pH. JLRs have found applications in wastewater treatment processes due to their high mass transfer rates. In JLRs, intrinsic high turbulence result in a very large air-liquid surface area for greater mass transfer. Therefore, in this study, ammonia removal by air stripping from synthetically prepared ammonia solution at the high pH in a semi-batch JLR due to its high mass transfer capabilities have been investigated. Investigated parameters in a JLR were initial ammonia concentration (10–500 mg/L), temperature (20–50 °C), air flow rate (5–50 L/min) and liquid circulation rate (35–50 L/min). While it was demonstrated that temperature and air flow rate have a significant effect on the ammonia removal, it was determined that initial ammonia concentration and liquid circulation rate have no significant effect on the ammonia removal. The overall volumetric mass transfer coefficients (K_La) have been calculated from obtained model and it was determined that increasing temperature and air flow rate have a very significant effect on K_La. It was concluded that JLR provides higher mass transfer capabilities than other type of reactors even if less air is given.     

Synthesis of medium-chain glycerides using lipase from Candida rugosa

Enzymatic synthesis of medium-chain glycerides (MCG) from capric acid and glycerol was studied using lipase from Candida rugosa. The effects of various reaction parameters such as time, molar ratio of substrates (mmol capric acid/mmol glycerol), amount of lipase, type of organic solvents, and initial water activity (a _w ) were studied. The best conditions tested for MCG synthesis at 37°C were, respectively, time, 24 h; molar ratio of substrates, 2.5; and amount of lipase, 100.0 mg. The use of organic solvents greatly influenced the activity of lipase in the synthesis of MCG. Generally, activity of lipase was high in nonpolar solvents with log P values from 3.50 to 4.50, where P is the partition coefficient between water and 1-octanol. The enzymatic synthesis of MCG was preferably carried out at an initial a _w of 0.328, which resulted in maximal yield. Analysis of the products of reaction using gas chromatography showed that lipase from Candida rugosa seemed to produce more dicaprin and tricaprin than monocaprin.     

Synthesis of block copolymers by the combination of chain transfer polymerization and initer process

Radical polymerizations of styrene (St) and methyl methacrylate (MMA) were carried out in the presence of tri phenylmethyl mercaptan (TPMM) as a chain transfer agent to give trityl (triphenylmethyl) terminated polymers. Transfer constants were found to be 17.8 and 0.71 for St and MMA, respectively. Trityl terminated polymers served as thermal “INITERS” for polymerization of vinyl monomers which proceeded via a quasi-living radical mechanism. This procedure makes it possible to prepare block copolymers. © John Wiley & Sons, Inc.     

Preparation of glycerides by controlled esterification

A simple procedure for esterifying glycerides without interesterification occurring would be highly useful for preparing on a large scale a number of tailor-made fats, including cocoa butter-like fats. Such esterifications were carried out by employingp-toluenesulfonic acid as catalyst and continuously removing the water of esterification by azeotropic distillation with aliphatic hydrocarbons or by stripping with vaporized hydrocarbons. Even thoughp-toluenesulfonic acid rapidly disproportionated 1-monostearin, even at 120C, apparently esterification was faster and only a moeerate amoung of ester-ester interchange and acidolysis occurred. Diacid glycerides might be prepared from monoglycerides by the procedure which was employed. Saturated diglycerides were esterified with oleic acid with little ester-ester interchange or acidolysis occurring; however, intraesterification was extensive. The reaction between 1,3-distearin and oleic acid yielded approximately 75% 1-oleodistearin and 25% 2-oleodistearin. Saturated diglycerides were esterified with sebacic acid, again with little or no interesterification occurring. Presented at the AOCS meeting in New Orleans, La., 1962; and at the VIth Congress of the International Society for Fat Research, London, England, 1962. A laboratory of the So. Utiliz. Res. and Dev. Div., ARS, U.S.D.A.     

Mass transfer behaviour of gas-liquid jet loop reactors

A special type of jet loop reactor (JLR), designed for continuous operation and short residence times was investigated with regard to its mass transfer behaviour, described by the volumetric mass transfer coefficient k_La. The jet stream and superficial gas velocities are varied in two JLRs of different sizes, equipped with different nozzles. Fully desalinated water, 0.08 molar NaCI solution and solutions of different concentration of carboxymethyl cellulose (CMC) are used as the liquid phase. A steady-state physical method is employed to determine k_La: air oxygen is purged from the liquid phase by gaseous nitrogen. The measurements show that the reactor is characterized by high power density and high mass transfer performance. No limit of mass transfer capacity was observed in the chosen ranges of volumetric gas and liquid flow rates, i.e. at a given jet stream velocity, the relationship between k_La and the superficial gas velocity is nearly linear. The investigations show that the mass transfer contributed by the jet stream largely depends on liquid phase composition.