A Novel Ultrafine Ru-B Amorphous Alloy Catalyst for Glucose Hydrogenation to Sorbitol

Glucose hydrogenation to sorbitol is of great industrial importance since sorbitol is widely used as the additive in foods, drugs, cosmetics, and as an intermediate in the vitamin C synthesis. Besides small amount of sorbitol can be obtained naturally from red seaweed and some fruits, commercial large scale production of sorbitol has always relied on the hydrogenation of glucose, in which Raney Ni catalyst is frequently used1-3. In order to enhance the catalytic efficiency and overcome the e…     

The effect of alternative carbohydrates on the growth and antibody production of a murine hybridoma

A murine hybridoma (CC9C10) was adapted to grow in media containing alternative carbohydrates to glucose. Cell yields relative to the glucose-based culture decreased in order of the following supplements: glucose = maltose > galactose > fructose = sorbitol = xylitol, although significant yields (> 50% of glucose control) were observed in all cultures. In the absence of glucose, glutamine consumption rates were enhanced significantly. Antibody production was directly related to the viable cell concentration in each culture and was independent of the phase of culture. A high specific antibody productivity (qMab) was observed in the cultures containing the polyols, sorbitol, or xylitol, even though the cell yields and growth rates were lower than the glucose-based control. The measured qMab in the xylitol culture was 5.6x that of the glucose culture and the volumetric yield of MAb was 29% higher.     

Sorbitol and gluconic acid production using permeabilized Zymomonas mobilis cells confined by hollow-fiber membranes

Immobilization of Zymomonas mobilis by different methods was investigated. Experiments were performed order to choose the most appropriate support for the immobilization of the cells. The most advantageous option was to use permeabilized cells in the bore of microporous hollow fibers. Whereas the reaction rate was about 33 g of gluconate/ (g of protein·h) using hollow fibers, which is comparable to that observed by using free cells, the calcium alginate immobilized cells presented a reaction rate of 4 g of gluconate/ (g of protein·h). These results can be explained by the mass transfer resistance effect, which, indeed, was much lower in the case of hollow-fiber membranes than in the alginate gel beads. A loss of enzymatic activity during the reaction was observed in all experiments, which was attributed to the lactone produced as an intermediate of the reaction.     

二亚(3,4-二甲基)苄基山梨糖醇的合成与表征

山梨糖醇与3,4-二甲基苯甲醛在酸催化下缩合成聚丙烯透明成核剂——二亚（3,4-二甲基）苄基山梨糖醇。实验结果表明,在3,4-二甲基苯甲醛66mmol,n（醇）：n（醛）=1．0：2．0,ω（催化剂）=0．6％-1.2％（以反应单体的质量计算）,ω（促进剂）=15％～18％（以反应物的总质量计算）,回流反应5h的最佳反应条件下,收率在96.5％以上。     

超细非晶态NiWB合金的制备及葡萄糖加氢性能的研究

通过改变溶液中的Na~2WO~4浓度以化学还原法制备了一系列超细非晶态NiWB合金,并用于葡萄糖高压液相加氢制取山梨醇。研究表明NiWB合金的催化活性均远高于RaneyNi。同时XPS揭示了钨的加入可以调变元素态硼的给电子能力,进而影响硼对羰基的活化和镍对氢的解离吸附能力。在活性最佳的NiWB-3合金上的基本动力学研究表明,葡萄糖加氢反应对氢压为一级,对葡萄糖浓度为零级,在373～403K范围内的反应活化能为54.7kJ·mol^-^1。     

焙烧温度对Ni/La(Ⅲ)催化剂氢解山梨醇制备低碳二元醇性能的影响

采用水热法合成了纳米棒状La(OH)₃载体,通过湿式浸渍方法制备了10%Ni/La(Ⅲ)负载型催化剂,考察了500~800℃不同焙烧温度对于催化剂氢解山梨醇制备低碳二元醇的影响,结合XRD、SEM/EDS、BET、H₂-TPR-MS、CO/CO₂-TPD-MS、TG和ICP-AES等表征手段对Ni/La(Ⅲ)催化剂的构效关系进行了分析。结果表明,Ni/La(Ⅲ)催化剂表现出高的氢解反应活性,在较低的焙烧温度下(500℃)催化剂主要以NiO/La₂O₂CO₃结构形式存在。随着焙烧温度的升高,NiO/La₂O₂CO₃逐渐向La₂NiO₄-La₂O₃进行转变。碱性是影响不同催化剂活性的决定因素,高的焙烧温度促进了催化剂中强碱性位的生成,显著提高了氢解反应活性,但对液体产物的选择性无明显影响,在220℃、4MPa H₂、1.5h的条件下,山梨醇完全转化,低碳二元醇的产率可达到53%。低的焙烧温度则增加了催化剂的水热稳定性。催化剂的失活主要归结于活性金属粒子在水相反应中从载体表面脱落而发生团聚,降低氢解反应活性。     

Analysis of the Dynamic Crystallisation of Isotactic Polypropylene/α-Nucleating Agent Systems by DSC

The nucleation efficiency of dibenzylidene sorbitol, methyldibenzylidene sorbitol and 1,2,3,4-bis- (3,4-dimethylbenzylidene) sorbitol in the crystallisation of the monoclinic phase of isotactic polypropylene has been evaluated by differential scanning calorimetry as a function of cooling rate and nucleation agent concentration. In order to analyse the nucleation activity of the additives, the self-nucleation process of the pure polypropylene has also been studied by thermal techniques. A large increment in the crystallisation temperatures has been obtained even for the lowest additive concentration, and the nucleating efficiencies are of the highest observed for α-nucleating agents in isotactic polypropylene. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermodynamic investigation of several natural polyols (II)

The low-temperature heat capacity C _p,m of sorbitol was precisely measured in the temperature range from 80 to 390 K by means of a small sample automated adiabatic calorimeter. A solid-liquid phase transition was found at T=369.157 K from the experimental C _p-T curve. The dependence of heat capacity on the temperature was fitted to the following polynomial equations with least square method. In the temperature range of 80 to 355 K, C _p,m/J K⁻¹ mol⁻¹=170.17+157.75x+128.03x ²-146.44x ³-335.66x ⁴+177.71x ⁵+306.15x ⁶, x= [(T/K)−217.5]/137.5. In the temperature range of 375 to 390 K, C _p,m/J K⁻¹ mol⁻¹=518.13+3.2819x, x=[(T/K)-382.5]/7.5. The molar enthalpy and entropy of this transition were determined to be 30.35±0.15 kJ mol⁻¹ and 82.22±0.41 J K⁻¹ mol⁻¹ respectively. The thermodynamic functions [H _T-H _298.15] and [S _T-S 298.15], were derived from the heat capacity data in the temperature range of 80 to 390 K with an interval of 5 K. DSC and TG measurements were performed to study the thermostability of the compound. The results were in agreement with those obtained from heat capacity measurements.     

Hydroxyoligophosphites and -Phosphonites on the Basis of 1,4:3,6-Dianhydro-D-sorbitol

The interaction of 1,4:3,6-dianhydro-D-sorbitol with phosphorous and phenylphosphonous acid amidochlorides leads to oligophosphites and -phosphonites with free hydroxyl groups on the periphery of their molecules. The obtained compounds were introduced into reactions via the transformation of trivalent phosphorus and hydroxyl groups.     

高效毛细管电泳－安培检测法测定牙膏中丙三醇和山梨醇

用高效毛细管电泳－安培检测装置，以２００μｍ铜圆盘电极为工作电极，在碱性介质中，建立了分离测定丙三醇和山梨醇的最佳实验条件。结果表明：平均理论塔板数为２．４×１０５／ｍ，丙三醇和山梨醇的浓度检测限分别为３００μｇ／Ｌ和２００μｇ／Ｌ，线性范围接近３个数量级。在５．００～５０．０ｍｇ／Ｌ内，丙三醇和山梨醇的相关系数分别为０．９９９７和０．９９９５。样品测定结果与用高效液相色谱法测定的结果基本一致，回收率在９２％～１０４％之间