从植物纤维原料中水解糠醛

介绍了从植物纤维中水解糠醛的生产方法及工艺，并讨论了糠醛收率的影响因素及其用途。     

重过磷酸钙法植物纤维水解生产糠醛

在实验室实验条件下,以重过磷酸钙为催化剂,植物纤维为原料,探讨了生产糠醛的适宜条件,当催化剂质量分数为１５％,固液比为１：０．４５,操作压力为１．０ＭＰa,水解 时间为３h时,糠醛产率可达１５％左右,残渣是一种优良的有复合肥,该法是一种有利于环境保护的生产方法。     

植物纤维原料水解生产乙醇的研究进展

本文对以植物纤维原料生产乙醇的国内外发展趋势和研究进展进行了综述,对该领域今后的研究重点进行了展望,并认为植物纤维原料生产乙醇将逐步形成一个重要的产业,要加强植物原料预处理研究,加强对纤维素降解机理、现代生物技术以及水解新方法等的研究,强化对植物资源的高效利用。     

植物纤维原料酶水解制取燃料乙醇的研究

综述了植物纤维原料酶水解制燃料乙醇的几种常见预处理方法,两步法发酵和同步糖化发酵,国内外植物纤维酶水解法制燃料乙醇产业化现状并总结了目前酶水解制取燃料乙醇存在的问题及对应的对策。     

纤维素酶水解纤维素还原糖的测定

对不同类菌种在不同培养基中的酶活性进行比较,测定了其底物得糖率,最高达８．５９％,可对纤维素酶的进一步研究提供实验参照。     

植物纤维制取草酸新工艺

研究了以植物纤维为原料用氧化－水解－氧化法制备草酸的工艺方法,以玉米秆,玉米芯,稻糠,玉米淀粉渣为原料,制取的草酸二水合物收率分别可达：69．7％,78．85,75．8％,83．4％。     

植物纤维原料纤维素酶水解的研究

以麦草为原料,探讨纤维素酶水解植物纤维的适宜条件。麦草含大量的纤维素和聚戊糖,其中的纤维素在纤维素酶的作用下分解生成葡萄糖和纤维二糖。对温度,pH值,酶解时间,酶用量分别进行单因素实验,通过测定葡萄糖含量和总还原糖含量,找出酶水解麦草的适宜条件为:pH4.6,温度47℃,酶解时间48h,酶用量7.5IU(每克绝干原料)。对不同底物浓度的实验表明,在尽可能高的底物浓度下连续水解,产物浓度高,得率也高。     

水解法制取乙酰丙酸

1前言天然纤维木素资源相当丰富。目前，我国农村每年就要烧掉三亿多吨秸杆作物。全世界每年植物纤维生长物，数量高达数百亿吨以上。这些资源不但容易得到，而且能够再生产，不断循环使用，可谓取之不尽，用之不竭的原料，可以设想，若干年之后随着水解化学的发展，很可能继石油化学之后在国民经济中居于重要地位，因此以纤维素为原料制取乙酰丙酸有着十分重要的意义。乙酰丙酸又名左旋糖酸，四氧代戊酸或隔酮酸，熔点33．5℃，有轻微的焦糖气味。其酸性与醋酸接近，纯乙酰丙酸的性质与冰醋酸接近易成过冷液体。2制备方法乙酸丙酸从1880年…     

草酸盐酸体系微晶纤维素水解动力学

对微晶纤维素在草酸-盐酸体系中的水解情况进行了研究,并对不同条件下反应产物中葡萄糖的质量浓度进行了测定。依据纤维素酸水解反应特点,根据Seaman模型,对微晶纤维素在草酸盐酸体系中的水解动力学规律进行了研究。动力学结果:纤维素水解和葡萄糖降解的活化能分别是58.02 k J/mol和144.2 k J/mol。升高反应温度,使纤维素水解反应速度加快,也会使葡萄糖的降解速率加快。该模型的最佳反应条件是:固液比1∶20 g/m L,草酸的质量浓度25 g/L,盐酸的质量浓度1 g/L,温度90℃,时间9 h,在此条件下,葡萄糖质量浓度为1.657 g/L。     

蛇纹石硫酸浸出过程动力学研究

首先确定了蛇纹石硫酸浸出过程中影响浸出速率的主要因素,以此为条件,对蛇纹石中MgO的浸出速率进行了研究。结果表明：MgO的浸出动力学能适用容积反应模型,其浸出速率可表示为样品中残留MgO量的二级反应,其表观活化能约为93.20kJ/mol,属化学反应控制。     

硫酸盐对硫酸催化水合萜脱水的影响

研究了不同浓度硫酸盐对硫酸催化水合萜脱水的影响 ,初步确立了此条件下硫酸催化脱水的最佳工艺条件。     

芳酮的Baeyer-Villiger反应机理及动力学研究

研究了用过氧马来酸作氧化剂时芳酮的Baeyer-Villiger反应机理,结果表明其在惰性气体保护下的反应机理为自由基和离子型机理共存。根据这一机理,建立了相应的动力学模型,并由实验得到了相关的动力学参数。     

硫酸介质中Ti/MnO_x型阳极的电化性能

本文用SEM和EDS研究了Ti／SnO2＋RuO2＋MnOx／MnOx电极的表面形貌和表面元素相对含量，考察了电极在20％H2SO4中的使用寿命，并用双位垒模型讨论了该电极的电化学性能，结果表明电极具有优良的电化学性能和较长的使用寿命．     

超浓乳液聚合苯乙烯—甲基丙烯酸的乳胶粒径及羧基分布

以苯乙烯、甲基丙烯酸为主要原料进行超浓乳液聚合 ,制备了含功能基的单分散性复合物。考察了乳化剂浓度、内相比、聚合程度对乳胶粒大小及分布的影响。同时 ,用电导滴定法测定了乳胶粒表面羧基的含量 ,探讨了乳化剂浓度、羧酸含量及内相比对羧基分布的影响。结果表明 ,随乳化剂浓度减小、内相比增加、聚合时间延长、乳胶粒径增大 ,随乳化剂浓度减小、内相比增加、粒子表面羧基减少 ,而羧酸含量对羧基分布的影响不太明显     

KINETICS OF Na+-H-ION EXCHANGE IN CONCENTRATED BUFFER SOLUTIONS OF SODIUM TETRABORATE AND BORIC ACID

Na⁺-H⁺ ion exchange between a fixed bed of Lewatite S 100 cationic ion exchange resin in R-H form and concentrated NaCl solutions at room temperature (298 K) and sodium tetraborate solutions at elevated temperature (338 K) was studied both experimentally and theoretically.

In the prediction of the break-through curves intraparticle and film diffusion resistances were considered. The variation of diffusion coefficient with the composition of the solid and liquid phases was accounted for by application of a Nernst-Planck model.

The shape of the break-through curves is very different in the two systems studied. A very favourable shape in the case of Na⁺-H⁺ ion exchange from sodium tetraborate solutions is due to the influence of borate buffer properties on equilibrium. The results of the computer simulation are in good agreement with the experimental data.     

APPLICATION OF THE NRTL EQUATION TO SELECTED VLE DATA FOR THE SIMULATION OF THE CONTACT SULFURIC ACID PROCESS

The success of flowsheeting systems in modeling chemical processes is fundamentally dependent upon their ability to adequately represent the physical properties and thermodynamic quantities of the chemical system of interest. The nonideal H₂SO₂ and H₂O system poses particular difficulties both representing the physical properties and in modeling the adsorption-reaction step involved in the formation of sulfuric acid by the contact process. This paper proposes the use of suitable nonideal correlation equations such as Wilson and Renon's NRTL for the reduction of specially formulated VLE data to develop a correlation that overcomes the difficulties associated with calculating the mass and energy balances for this system. The approach presented here enables the user to make maximum use of the flowsheeting capabilities without adding user supplied subroutines. The results indicate improved agreement over previous modeling approaches for the calculation of the absorber energy balances in which the absorption-reaction step must be taken into account. The improvement is seen in closer agreement between plant and model outlet stream temperatures.     

超低压反渗透膜浓缩处理矿山酸性废水

从反渗透膜RE4040-BL和RE4040-BE的对比试验结果可知,选择超低压反渗透膜较为经济和合理.浓缩试验在压力为1.0MPa、温度为25℃下进行,原料液为100L结果表明:随着浓缩时间的增加,膜渗透液和浓缩液的离子浓度和截留率逐渐增加,而膜通量却逐渐减小;矿山酸性废水中Ni2 、Cu2 、Zn2 和Pb2 的离子浓度可分别浓缩至120.5、617、149.3mg/L和93.1mg/L,浓缩倍数分别为7.26、7.83、8.16和9.35.进一步浓缩后重金属离子可以回收利用.     

乙二醛溶液体系中乙酸络合萃取的动力学研究

采用恒界面池法研究了乙酸在乙二醛溶液中的萃取动力学,实验结果表明：萃取速率由界面化学反应所控制,且表观反应速率方程为：ｒ＝ｋｓＣＨＡｃ１．３６４１,在２５℃时的反应速率常数ｋｓ＝１．８２×１０－２ｍｏｌ／ｃｍ２·ｓ。此外,还研究了温度对反应速率的影响,求取了表观反应的活化能Ｅａ＝２３．２８３３ｋＪ／ｍｏｌ,从而进一步说明了萃取速率控制步骤为界面化学反应所控制。     

KINETICS OF PHENOL EXTRACTION FROM AQUEOUS PHASE BY SULFURIC ACID SALTS OF TRIOCTYLAMINE

The kinetics of the extraction of phenol from the aqueous phase by sulfuric acid salts of trioctylamine (TOA salts) in kerosene and the stripping of phenol from the organic phase by sodium hydroxide solution were studied using a constant interfacial area cell. Measurements of the extraction and stripping rates were made by measuring the time-dependent phenol concentrations in the aqueous phase. It is found that the extraction rate of phenol is strongly dependent on the initial concentration of phenol in the aqueous phase and on the initial concentration of TOA salts in the organic solvent. However, the effect of the total sulfate concentration and the acidic concentration on the extraction rate are not significant. The stripping rate is only a function of the initial concentration of phenol in the TOA salt-organic phase. By analyzing the experimental data, it was recognized that the extraction of phenol occurs at the interface, rather than in the bulk of the solution. The diffusion resistance, rather than the resistance of chemical reaction, is the rate-controlling step for the phenol extraction. Based on the experimental data, simple expressions of the extraction rate and stripping rate of phenol were obtained.