气相色谱测定三甲基乙酸合成液中三甲基乙酸的含量

采用内标法,利用填充柱测定了由异丁烯和一氧化碳经加压催化合成三甲基乙酸工艺的合成液中的三甲基乙酸。对三甲基乙酸合成液中的复杂组分进行了讨论,对几种定量分析方法进行了比较,解决了有机酸拖尾问题,选择了较适合的内标物。相对标准偏差为０．５％,回收率为１０８％。     

气相色谱法测定三甲基乙酸合成液中三甲基乙酸的含量

采用内标法 ,利用填充柱测定了由异丁烯和一氧化碳经加压催化合成三甲基乙酸工艺的合成液中的三甲基乙酸。对三甲基乙酸合成液中的复杂组分进行了讨论 ,对几种定量分析方法进行了比较 ,解决了有机酸拖尾问题 ,选择了较适合的内标物。相对标准偏差为 0 .5% ,回收率为 1 0 8%。     

丙烯酰胺料液pH值对测定丙烯酸含量的影响

对丙烯酰胺料液中丙烯酸含量测定结果不真实的原因进行分析，并提出应将料液pH值控制在4．5，将丙烯酸根完全转化为丙烯酸，可使测定的结果更准确。     

气相色谱法测定精馏塔塔底残液中的甲醇含量

建立了一种用毛细管柱气相色谱测定甲醇精馏塔残液中的甲醇残留量的方法:以硝基甲烷为内标物,水为溶剂,使用Factorfour VF-17ms毛细管柱,色谱仪进样器和FID检测器,温度均为200℃;柱室温度100℃。甲醇浓度在17～396 mg/100 mL范围内线性相关系数r=0.99960;方法的精密度高,测定结果的变异系数是3.6%;回收率在100.65%,该方法简便、快速、准确。     

气相色谱法测定水性涂料中的水分含量

本文介绍了气相色谱法在测定水性涂料中水分含量的方法，并结合实际工程情况及测定水分含量的影响因素进行了探讨和完善。     

关于测定水性涂料中水分含量方法的比较与实践

分别介绍了用气相色谱法和卡尔·费休法测定水性涂料中水分的含量,并结合实际情况讨论了测定中的影响因素。     

气相色谱法测定2-甲基-4-氯苯酚反应液中6种组分含量

采用气相色谱法测定2-甲基-4-氯苯酚反应液中6种组分的含量。通过优化色谱条件,样品中6种待测组分经TG-1701MS毛细管柱分离,使用氢火焰离子化检测器(FID)检测,以对甲酚为内标物,采用内标法定量,2-氯-6-甲基苯酚、邻甲酚(原料)、对甲酚(内标)、2,4-二氯-6-甲基苯酚、2-甲基-3-氯苯酚、2-甲基-4-氯苯酚(产物)、2-甲基-5-氯苯酚与相邻色谱峰分离较好,在测定浓度下有良好的线性关系,线性相关系数r均大于0.999;方法的回收率为97%～105%,相对标准偏差RSD<3%,符合分析方法的要求。该分析方法操作简便、准确度高,可为2-甲基-4-氯苯酚的工艺优化和中控分析提供有效数据。     

气相色谱法测定阳极电泳涂料中溶剂含量

建立了阳极电泳涂料中有机溶剂含量的顶空毛细管气相色谱分析方法。选用大口径HP-快速GC残留溶剂柱为分离柱,FID为检测器,内标法进行定量,并讨论了顶空平衡温度、平衡时间对测定的影响。分析结果表明：该方法对有机溶剂达到了完全分离,溶剂和内标乙二醇乙醚的不同质量比与其相应特征峰的峰面积之比有较好的线性关系,相关系数为0．9993～0．9997,测定结果的RSD为1．12％～2．65％,样品的回收率为98．87％～100．35％。     

气相色谱法测定反应液中N,O-双(三甲基硅基)乙酰胺的含量

建立了气相色谱法测定N,O-双(三甲基硅基)乙酰胺反应液的分析方法,采用SE-30弹性石英毛细管柱,柱温120℃,以邻二氯苯为内标物,以样品的进样量对样品峰面积与内标物的峰面积之比进行线性回归,各组分线性关系良好,相关系数为0.9991～0.9995。测定结果的相对偏差为1.54%。     

Recovery of lactic acid by batch reactive distillation

Lactic acid, being virtually a non‐boiling compound, is difficult to separate from its aqueous solution by conventional methods such as distillation. It is necessary to convert it to the relatively volatile ester and the separation of the ester, followed by hydrolysis, is recommended as an appropriate method of recovery. In the present work, we explore and investigate a novel reactive distillation strategy to perform esterification, distillation and hydrolysis in a single unit. The experiments were performed in a batch reactive distillation set‐up and the results have been explained with the help of an appropriate model. An unsteady state mathematical model based on an equilibrium stage concept was developed for batch reactive distillation. A pseudo‐homogeneous model was used for the determination of reaction kinetics. The effect of operating parameters such as feed concentration, mole ratio, catalyst loading, boil‐up rate, etc. on the recovery of lactic acid was studied with the help of simulation and experimental results. The feasibility issue of reactive distillation has been discussed based on the results obtained. Copyright © 2006 Society of Chemical Industry     

In situ reactive extraction of lactic acid from fermentation media

Extractive lactic acid fermentation was investigated in the presence of sunflower oil and Alamine‐336 (with oleyl alcohol as the diluent solvent). Lactic acid was produced in various media at 37 °C using Lactobacillus delbrueckii (NRRL‐B 445). First, the effects of oleyl alcohol (33.3%, v/v), immobilisation, and immobilisation in the presence of sunflower oil (5, 10, 15%, v/v) on lactic acid production were investigated. It was found that oleyl alcohol did not affect production while addition of sunflower oil increased lactic acid production from 10.22 to 16.46 gdm^?3. On the other hand, a toxic effect was observed for oleyl alcohol solutions containing 15–50% (v/v) Alamine‐336. A maximum total lactic acid concentration of 25.59 gdm^?3 was obtained when an oleyl alcohol solution containing 15% (v/v) Alamine together with immobilised cells with 15% (v/v) sunflower oil was used. This value was about 2.5 times that obtained from fermentation without organic solutions. © 2001 Society of Chemical Industry     

Hydrothermal catalytic conversion of biomass for lactic acid production

The production of lactic acid has increased owing to growing polymer markets, increased demand in the chemical sector and many applications in the food industry. Biomass hydrothermal decomposition is potentially a method for lactic acid production. To obtain a higher yield of lactic acid, the influence of metal ions (Zn(II), Ni(II),Co(II) and Cr(III)) on biomass decomposition in sub‐critical water (T = 300 °C) was investigated and the catalyst function in the complex reaction network of biomass degradation was discussed. In comparison with a non‐catalytic process, the addition of 400 ppm Ni(II) catalyst increased the yield of lactic acid from 3.25% to 6.62% at 300 °C and 120 s for microcrystalline cellulose. The lactic acid yield for glucose was 9.51% for 400 ppm Co(II) catalyst at 300 °C and 120 s. In the case of Cr(III) and Ni(II), the conversion of maize straw, sawdust and rice husk first increased, and then decreased from 0 to 800 ppm. For catalyst Cr(III), Zn(II) and Ni(II), the conversion of wheat bran indicated a decreasing trend. Transition metal ions have a great influence on raw materials conversion to lactic acid. In the conversion of pyruvaldehyde to lactic acid, the ionic catalyzed Cannizzaro‐type reaction would take place. Copyright © 2007 Society of Chemical Industry     

异辛酸合成液的气相色谱分析

建立了异辛酸合成过程中异辛醇、异辛酸和酯的气相色谱分析方法.以10 %改性聚乙二醇20M为固定液,苯乙酮为内标物,氢火焰离子化检测器,内标法定量分析异辛酸.实验结果表明,该方法准确可靠,测得异辛酸的相对重量校正因子为1.305,相对误差＜2.0 %.同时,通过与化学法对照结果显示,合成液用内标法测定较好,而精产品用带校正因子的归一化法测定较好.     

乳酸提纯反应精馏新工艺非平衡级稳态模拟

Purification of lactic acid by reactive distillation (RD) is a novel technology which has many excellent characteristics compared with traditional technologies. This paper presented a non-equilibrium model for lactic acid purification RD pilot column. An Improved Separation Efficiency Function (ISEF) was proposed based on de-coupling and pseudo-homogenous assumptions, which greatly improved the solving efficiency and made this model suitable for practical application. Simulation results were consistent with the experiments in different conditions, and the simulation results outperformed the simulator ASPEN PLUS in which the equilibrium stage assumptions were adopted. The static characteristics of the pilot setup were also investigated. The analysis result could help to accelerate the commercialization of the lactic acid purification RD technology.     

乳酸的生产技术及其研究进展

综述了绿色平台化合物——乳酸的生产方法及其最新技术研究进展,分析了乳酸生产技术发展的现状。认为关键问题是一方面要进一步完善现有的生产技术,另一方面应开发新的绿色合成技术,实现高效大规模生产,降低生产成本,并对绿色合成技术发展方向进行了分析和探讨。     

聚（乳酸⁃乙醇酸）薄膜制备及其性能研究

以左旋乳酸（L?LA）和乙醇酸（GA）为原料,利用一步法熔融共聚合成聚（乳酸?乙醇酸）（PLLGA）共聚物,通过差示扫描量热仪（DSC）对共聚物薄膜的结晶性能进行了表征,并利用Avrami方程对其进行了等温结晶动力学研究,通过万能拉伸试验机和压差法气体透过仪对共聚物薄膜的力学性能和气体阻隔性能进行测试。结果表明,PLLGA共聚物薄膜中GA的引入对材料结晶性能有较大影响,在GA含量为4 %（摩尔分数,下同）的PLLGA中,GA表现为成核剂作用,共聚物结晶比纯聚左旋乳酸（PLLA）薄膜快,半结晶时间减少;而在GA含量为8 %的PLLGA中,GA则表现出限制分子链运动的作用,破坏共聚物分子间的规整度,导致材料结晶性能大幅度降低,处于非晶态;随着GA含量的增加,PLLGA薄膜的拉伸强度和弹性模量逐步下降,而断裂伸长率大幅度增加,GA含量为8 %的PLLGA的断裂伸长率达到了130.1 %,是纯PLLA薄膜的21.3倍;同时,PLLGA薄膜的气体阻隔性显著增加,5 ℃时,相比于纯PLLA薄膜,GA含量为8 %的PLLGA薄膜的O₂、CO₂、N₂透过量分别降低了47 %、41 %和39 %。     

Equilibria and kinetics for reactive extraction of lactic acid using Alamine 336 in decanol

Lactic acid is an important commercial product and extracting this from aqueous solution is a growing requirement in fermentation‐based industries. The design of an amine extraction process requires (i) equilibrium and (ii) kinetic data for the acid–amine (solvent) system used. The equilibrium complexation constants for ratios of (1:1) and (2:1) have been estimated. The kinetics of extraction of lactic acid by Alamine 336 in decanol has also been determined. The reaction between lactic acid and Alamine 336 in decanol in a stirred cell falls in Regime 3, ie extraction accompanied by a fast chemical reaction occurring in the diffusion film. The reaction has been found to be zero order in Alamine 336 and first order in lactic acid with a rate constant of 0.21 s^?1. These data will be useful in the design of extraction processes. © 2002 Society of Chemical Industry     

A continuous process for the recovery of lactic acid by reactive distillation

Separation and purification of lactic acid from the fermentation broth are difficult because of its non‐volatile nature and the presence of other organic acids. Esterification of lactic acid with methanol followed by hydrolysis of the separated methyl lactate is an effective technique for this purpose. A continuous process for recovery is proposed and various aspects are evaluated through simulation and experiments. In the proposed route, a vapor stream containing methyl lactate is removed from a two‐phase CSTR, used for esterification, operated under boiling conditions. The ester thus separated from the aqueous solution is further hydrolyzed in a reactive distillation column. Continuous removal of the volatile component (i.e. methanol) from the reaction zone increases conversion, thus pure lactic acid is obtained from the bottom of reactive distillation column. The results obtained in the experiments are compared with the simulation results. Further simulation studies were performed to obtain the suitable operating conditions for higher conversion and concentration of lactic acid. Copyright © 2006 Society of Chemical Industry     

我国乳酸市场发展前景广阔

介绍了我国乳酸、乳酸盐（酯）的生产现状,分析了我国乳酸的生产消费及发展趋势。随着发酵技术的飞速发展,极大地推动了乳酸行业的发展,市场前景十分广阔。