丙烯腈－苯乙烯共聚物水解磺化产物对泥浆的稳定作用

在实验室条件下对用丙烯腈－苯乙烯共聚物在硫酸存在下的水解磺化产物（ＨＳＡＳ）处理的泥浆性能进行了评定。ＨＳＡＳ处理的泥浆有较小的滤失性，较好的耐盐和抗高温性。     

Development of catalysts for hydrogen generation from hydride compounds

Catalytic hydrolysis of NaBH₄ and NH₃BH₃ has been studied. It was shown that the nature of the support and the active component of the catalyst affect the H₂ generation rate. Despite similar sizes of rhodium particles formed on the surface of different supports (γ-Al₂O₃, TiO₂, carbon), their reactivity is different. Rh/TiO₂ with low rhodium concentration (1 wt.%) is the most active catalyst both in the hydrolysis of NaBH₄ and NH₃BH₃. The obtained results show that the rhodium chloride interaction with titania determines the reactivity of rhodium particles formed under action of NaBH₄ medium. TEM, DRS UV–vis and XPS were used to characterize the catalysts.     

Kinetic study of the hydrolysis of isocyanic acid in the gas phase

The hydrolysis of isocyanic acid in the gaseous phase has been investigated at temperatures between 553 and 613 K by mass spectrometry and evaluated to obtain the corresponding kinetic data. The reaction order and reaction constant have been determined. Finally, the influence of water on the catalysed formation of melamine from isocyanic acid under the operating conditions employed has been investigated in order to determine whether there is a need to try the process gas.     

水解母液生产葡萄糖酸钙新工艺

葡萄糖酸钙的生产一般是以淀粉为原料经液化、糖化、发酵、中和、精制、结晶、干燥制得的。而以母液为原料，其原料成本低，工艺流程短，减少了营养元素的添加，大幅度地降低了生产成本，值得推广。     

空气湿固化含硅丙烯酸酯的制备与表征

通过甲基丙烯酸甲酯、丙烯酸丁酯、γ-甲基丙烯酰氧丙基三甲氧基硅烷制备了空气湿固化胶黏剂,使其在pH=7时水解交联。采用H1NMR及FTIR和气象色谱对其结构交联情况做了详细分析,并对溶液膜的性能做了一系列的测试比较。     

Kinetics of cellobiose decomposition under subcritical and supercritical water in continuous flow system

The effects of reaction temperature, pressure and residence time were investigated with a flow apparatus. Cellobiose decomposition kinetics and products in suband supercritical water were examined at temperatures from 320 to 420 °C at pressures from 25 to 40 MPa, and at residence times within 3 sec. Cellobiose was found to decompose via hydrolysis and pyrolysis. The yield of desired hydrolysis product, glucose, was the maximum value of 36.8% at 320 °C, 35 MPa, but the amount of 5-(hydroxymethyl)furfural (HMF), fermentation inhibitor increased too because residence time increased in the subcritical region owing to decrease of reaction rate. Meanwhile, though the yield of glucose is low in the supercritical region, the yield of HMF decreased compared with the subcritical region; and at the minimum yield of HMF (380 °C, 25 MPa), the yield of glucose was 21.4%. The decomposition of cellobiose followed first-order kinetics and the activation energy for the decomposition of cellobiose was 51.05 kJ/mol at 40MPa.     

Environmental etch performance, and scratch and mar of automotive clearcoats

Environmental etch damage to automotive coatings, and scratch and mar of these coatings are an important element of customer satisfaction as well as a significant warranty repair consideration for automotive companies. The conditions that result in environmental etch are examined and a laboratory test proposed. Data from this test are compared to automotive hoods exposed in Florida. The performance of various crosslinking chemistries is discussed and the requirements for improved environmental etch are outlined. Scratch and mar performance of these systems is also reviewed. We have found that coatings respond to physical stress by elastic recovery, by plastic flow and by brittle fracture. Classifying types of damage in this way is important for understanding the chemistry needed for improved scratch and mar of coatings.     

Surface chemistry and kinetics of the hydrolysis of isocyanic acid on anatase

In order to meet the stricter NO_x and particulate emission limits for commercial vehicles, the selective catalytic reduction (SCR) with urea is currently seen having the highest potential. The conversion of urea into ammonia and carbon dioxide consists of two consecutive reactions, in which isocyanic acid is an intermediate that is hydrolyzed over TiO₂. The intrinsic kinetics and the surface chemistry for this reaction are explored. Up to a temperature of 132 °C the reaction was in the intrinsic kinetic regime (E_A = 73 kJ/mol), while at higher temperatures the reaction was limited by pore and external diffusion constraints, respectively. In the presence of NO, NH₃ and NO₂, the catalytic activity was negatively influenced, increasing in severity in the sequence mentioned indicating that nitrates formed from NO₂ were most effective in blocking cations and anions of TiO₂. IR spectroscopy indicates that dissociative adsorption of HNCO on TiO₂ forms Ti–NCO and hydrogen bonded OH species. In the presence of water, isocyanic acid was so rapidly hydrolyzed that only adsorbed ammonia was observed on the catalyst surface. The presence of NO, NH₃ and NO₂ retards hydrolysis leading to the appearance of isocyanate species on the surface.     

Hydrothermal synthesis of LA-MN-Hexaaluminates for the catalytic combustion of methane

Hydrothermal synthesis by using urea hydrolysis at 1.0-3.0 MPa and 120-130 ‡C was employed to prepare Mn-substituted hexaaluminate catalysts for methane combustion. The results from DTA-MS demonstrated that CO_3- and Off anions co-exist in the hydrothermal reaction. XRD reveals that the components of carbonates and hydroxides in the hydrothermal reaction are more favorable than those in the (NH₄)₂CO₃ co-precipitation for the formation of the Mn-substituted hexaaluminate phase. After calcination at 1,200 ‡C for 2 h, LaMnAl₁₁O₁₉ is the major phase of the catalyst prepared by the hydrothermal synthesis method while LaAlO₃ is the major one of the catalysts prepared by NH₄OH and (NH₄)₂CO₃ co-precipitation. The catalyst prepared by hydrothermal synthesis has higher activity than that prepared by NH₄OH and (NH₄)₂CO₃ co-precipitation. The major reason is that more Mn²⁺ ions have incorporated into the hexaaluminate lattice. The effect of drying methods on the formation of hexaaluminate phase was also discussed.     

青霉素酰化酶基因工程菌 E.coli A_(56)(pPA22)水解青霉素 G 的动力学

用初速度法测定了青霉素酰化酶基因工程菌 E.coli A_(56)(pPA22)游离细胞和固定化细胞水解青霉素 G 的动力学常数,并进行了动力学模型的检验。该菌体酶活高,米氏常数小,固定化后米氏常数和苯乙酸抑制常数增大,底物抑制常数和6-APA 抑制常数没有变化。通过青霉素 G 裂解过程的考察,验证了青霉裂解动力学模型的适用性及动力学常数测定的可靠性。