Problems and Possibilities of the Free-Radical Addition of Thiols to Unsaturated Compounds

In view of the growing importance of photochemically initiated reactions in industry, the use of free-radical additions of thiols to unsaturated compounds also seems promising. The present article is intended to demonstrate the possibilities and limitations of reactions of this type in organic synthesis.     

Possibilities of Microporous and Hierarchical MFI Zeolites in the Synthesis of Nitrogen Heterocyclic Compounds

Kinetics and Catalysis - The catalytic properties of a microporous H-ZSM-5 zeolite and a granular hierarchical H-ZSM-5h zeolite in the synthesis of basic pyridines and quinolines have been studied....     

Production of Organophosphorus Compounds from Hydrogen Phosphide

Abstract

Technical processes for the production of PH₃ and for its radical induced addition to nonactivated olefins are detailed. The influence of the reaction conditions chosen on the selectivity of the PH₃/Olefin-reaction is discussed.     

六苄基六氦杂异伍兹烷五种氢解脱苄化合物的合成及工业制备

综述了六苄基六氮杂异伍兹烷（HBIW）五种氢解脱苄化合物的合成条件和工业制备工艺。这五种化合物是：四乙酰基二苄基六氮杂异伍兹烷（TADBIW）、四乙酰基二甲酰基六氮杂异伍兹烷（TADFIW）、四乙酰基六氮杂异伍兹烷（TAIW）、四乙酰基二乙基六氮杂异伍兹烷（TADEIW）和六乙酰基六氮杂异伍兹烷（HAIW）。其中的TADBIW系由HBIW经一次氢解合成，其它四种都系由HBIW经两次氢解合成。HBIW的这五种氢解脱苄化合物均可经硝解合成六硝基六氮杂异伍兹烷（HNIW）。另外，本文总结了HBIW及其五种氢解脱苄产物的红外、核磁和质谱数据及它们的基本性能参数。     

六苄基六氮杂异伍兹烷五种氢解脱苄化合物的合成及工业制备

综述了六苄基六氮杂异伍兹烷(HBIW)五种氢解脱苄化合物的合成条件和工业制备工艺。这五种化合物是:四乙酰基二苄基六氮杂异伍兹烷(TADBIW)、四乙酰基二甲酰基六氮杂异伍兹烷(TADFIW)、四乙酰基六氮杂异伍兹烷(TAIW)、四乙酰基二乙基六氮杂异伍兹烷(TADEIW)和六乙酰基六氮杂异伍兹烷(HAIW)。其中的TADBIW系由HBIW经一次氢解合成,其它四种都系由HBIW经两次氢解合成。HBIW的这五种氢解脱苄化合物均可经硝解合成六硝基六氮杂异伍兹烷(HNIW)。另外,本文总结了HBIW及其五种氢解脱苄产物的红外、核磁和质谱数据及它们的基本性能参数。     

木质素基酚类化合物加氢脱氧制取碳氢燃料

木质素是生物质中碳资源密度最高的组分.木质素到高品质液体燃料的转化主要通过其解聚的单环酚类化合物经加氢脱氧工艺来实现.来源于木质素的酚类化合物的加氢脱氧产物一般为C6~C10之间的碳氢化合物,与现有的商品汽油组分碳数分布一致,是理想的交通替代燃料.酚类化合物的加氢脱氧研究近年来发展迅速,文献报道数量激增.本文对硫化态Mo基催化剂、贵金属催化剂及非硫化非贵金属催化剂作用下单环酚类化合物的加氢脱氧反应特性分别进行了回顾,对典型酚类模型化合物在催化反应机理进行了简述,并对载体材料在加氢脱氧过程中的作用进行了介绍.随后,在此基础上总结了当前酚类化合物加氢脱氧过程中的难点,并对下一步的技术发展方向进行展望.     

Evaluation of the Use of Elicitors for the Production of Antioxidant Compounds in Liquid Cultures of Ganoderma curtisii from Costa Rica

The use of substances or conditions as elicitors can significantly increase the production of secondary metabolites. In this research, the effects of different elicitors on the production of antioxidant secondary metabolites were evaluated in a strain of Ganoderma sp. The elicitors tested were pH changes in different growth phases of the fungus (pH 3, 5.5 and 8), different concentrations of peptone as a nitrogen source (1 g/L and 10 g/L), and the addition of chemical agents to the culture medium (ethanol, growth regulators, and salts). The alkaline pH during the stationary phase and the high availability of nitrogen were effective elicitors, producing cultures with higher antioxidant activity (37.87 g/L and 43.13 g/L dry biomass) although there were no significant differences with other treatments.     

Intermetallic Compounds and the Use of Atomic Radii in Their Description

Metallic radii, which are obtained from atomic distances in the pure elements, are generally used for the calculation of distances in intermetallic compounds. However, the procedure for using such radii depends on the individual structural type: (a) For high coordination numbers and only slightly differing distances between atoms of the same kind and different atoms, all distances in a structure are proportional to the sum of radii, weighted according to the compositon. Such a “Vegard” relationship for ordered compounds is obeyed by intermetallic compounds with topological close packings, but strictly only if the various kinds of distances are correlated via symmetry relationships. For compounds with low coordination numbers the simple sum of radii holds for atoms participating in the shortest bond (e.g. in ionic crystals).-(b) The number of neighbors determines the size of each atom. It can be shown that the bond strength-bond length concept, developed for valence compounds, and often dealt with in the literature over the last ten years, is also applicable for alloys. On this basis a formalism is developed which uniformly describes the size of the atoms as a function of the coordination number for both the limiting cases of multiple bonds in molecules and for close packed atomic arrangements in alloys.     

Use of Heteropoly Compounds in Natural Gas Sweetening and Sulfur Recovery

Among the numerous H₂S removal methods developed by now, liquid redox process with iron chelate base absorbent has gained the most attention, but the amendment of absorbent stability is still a problem^[1,2]. An innovative approach to liquid redox process involving the use of heteropoly compounds appears to be a promising resolution to natural gas sweenting and sulfur recovery, to which an introduction will be given in this presentation.     

Use of FTIR spectroscopy in the investigation of catalytic reactions in zeolites—Possibilities and limitations

FTIR-spectroscopic investigations of catalytic reactions yield detailed information about the interaction of adsorbed molecules with the catalyst and kinetic data of the surface reaction, if the participating molecules show vibrations whose position and intensity in the IR-spectrum depend on the sorption state and the quantity adsorbed. In this paper, the possibilities and limitations of the method are represented by two examples.     

Use of Tetramethylthiuram Disulfide in Synthesis of Nitrogen-containing Heterocyclic Compounds

We have developed a method for synthesis of aryl isothiocyanates by means of thiocarbamoylation of aromatic amines by tetramethylthiuram disulfide followed by degradation of the intermediate N₍₁₎-aryl-N,N-dimethylthiourea by concentrated HCl. We have shown that thiocarbamoylation of 4-amino-5-ethyl-4H-1,2,4-triazole-3-thiol occurs at the 2 position of the triazole ring, while thiocarbamoylation of 4-amino-3-methyl-6-phenyl-4,5-dihydro-1,2,4-triazin-5-one leads to the dihetaryl-substituted thiourea. We consider the possibility of using N₍₁₎-aryl-N,N-dimethylthioureas as analogs of isothiocyanates in reactions with N-nucleophiles.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 775–780, May, 2005.     

Formation of Aldehyde and Ketone Compounds during Production and Storage of Milk Powder

Certain aldehyde and ketone compounds can be used as indicators, at a molecular level, of the oxidized flavor of milk powder instead of sensory evaluation. This study investigated the formation of aldehyde and ketone compounds as affected by the heat-related processing and storage of milk powder. The compounds were extracted by solid phase microextraction fiber and determined using gas chromatography-mass spectrometry. In the results, higher contents of hexanal, 2-heptanone, octanal and 3-octen-2-one were detected in concentrated milk and fresh milk powders than in raw milk and heated milk. The levels of these compounds increased with increasing time of storage of milk powder. Meanwhile, the DPPH radical scavenging activity decreased and peroxide value increased during the production and storage of milk powder. In addition, the pore volume distribution of milk powder particle was determined by nitrogen isotherm adsorption. The porosity of milk powder was significantly correlated to the changes of aldehyde and ketone compounds during storages periods of 3 months (r > 0.689, p < 0.05) and 6 months (r > 0.806, p < 0.01). Therefore attention should be paid to the detectable aldehyde and ketone molecules to control the oxidized flavor, which was influenced by pre-heating as well as concentration and drying during milk powder production.     

Some Possibilities and Limitations of Contactless Impedimetric Determinations of Organic Liquids in Aqueous Solutions. The Interference from Ionic Compounds

The possibilities of impedimetric determinations of organic liquids in mixtures with aqueous solutions have been studied in detail, using a planar capacitor cell combined with multivibrator and operational amplifier circuits functioning as a differentiator and a system of dioxane with aqueous solutions of alkali halides. The experimental values have been compared with a simple model and the detector response has been characterized. The behaviour of the detection cell can be reliably predicted on this basis. This approach permits extremely simple, rapid and cheap analyses of binary liquid mixtures, however, it suffers from a serious limitation in that the overall electric conductivity of the mixture must be low.     

超临界水气化有机物制氢研究

针对一些有机物的超临界水气化（SCWG）制氢过程,分别概述了模型有机物如葡萄糖、甲醇、纤维素、木质素和真实生物质及有机废物/水的影响因素、中间产物及反应路径;分析了均相催化剂如碱、碱金属盐和非均相催化剂如ZrO₂、活性碳、贵金属、过渡金属的催化气化效率及催化机理,并指出非均相催化SCWG过程是SCWG技术的重要发展方向;对SCWG制氢过程热力学进行初步的讨论;简要介绍了目前世界上的3套SCWG制氢中试装置的运行情况,提出SCWG过程工业化应用的难点及未来技术的发展方向。     

Aromatic Compounds Production from Sorbitol by Aqueous Catalytic Reforming

The rules on regulating aromatic compounds production was investigated by aqueous cat-alytic reforming of sorbitol. It was found that aromatics, ketones, furans, organic acids were main compounds in organic phase. The obvious e ect of metal content showed that the highest carbon selectivity of aromatics was 34.36% when 3wt% Ni content was loaded on HZSM-5 zeolite modi ed by MCM-41. However, it was decreased only to 4.82% when Ni content was improved to 20wt%. Meanwhile, di erent reaction parameters also displayed important impacts on carbon selectivity. It was improved with the increase of temperature, while it was decreased as liquid hourly space velocity and hydrogen pressure was increased. The results showed that appropriate higher temperature, longer contact time and lower hy-drogen pressure were in favor of aromatics information, which suggested a feasible process to solve energy crisis.     

Use of Molecular Imprinted Polymers for the Separation and Preconcentration of Organic Compounds

Data on the use of molecular imprinted polymers for the separation and preconcentration of organic substances in chemical analysis are summarized. The main approaches and methods used in the synthesis of these polymers are considered. The development of combined and hybrid methods of analysis with the use of these adsorbents is discussed.     

水蒸气重整生物质裂解油及其模型分子制氢*

随着能源枯竭和环境日益恶化,利用可再生的生物质裂解油或其模型分子重整制氢逐渐引起人们重视。本文结合国内外重整制氢的研究进展,从催化剂、反应过程和反应机理三个方面对生物质裂解油及其模型分子(乙醇、乙酸、乙二醇、丙三醇、葡萄糖和苯酚等)水蒸气重整制氢研究现状进行了回顾。在重整催化剂方面主要对贵金属和过渡金属催化剂的研究进展进行了总结,对一些新的重整过程如液相重整等也进行了介绍。在反应机理方面主要是对乙醇、乙酸、乙二醇和葡萄糖在重整反应中的反应路径进行了归纳。此外,对水蒸气重整反应中遇到的问题如积碳和副产物的产生等也进行了详细的分析,并对生物质制氢未来发展的方向进行了展望。     

Vanadium Catalysts Promoted with Magnesium Compounds for Production of Sulfuric Acid

The feasibility and efficiency of promotion with magnesium compounds of supported and mixed catalysts for sulfuric acid production were studied.