氧化铝的改性及其在合成气直接制二甲醚反应中的应用

 采用浸渍法制备了经硼、磷和硫的含氧酸根阴离子改性的γ-Al2O3, 以其为甲醇脱水活性组分,与铜基甲醇合成活性组分CuO-ZnO-Al2O3组成双功能催化剂,并在连续流动加压固定床反应器上考察了催化剂对合成气直接制二甲醚反应的催化性能. 结果表明, SO2-4改性可以显著提高γ-Al2O3的甲醇脱水活性,从而提高产物中二甲醚的选择性和一氧化碳的转化率. 此外,还详细研究了SO2-4改性条件如SO2-4含量、焙烧温度及前驱物种类的影响. 结果表明,当SO2-4含量为10%, 焙烧温度为550 ℃时,二甲醚的选择性及一氧化碳的转化率最高; SO2-4前驱物的种类对其改性效果的影响很小.     

Nitroformonitrile oxide

Two methods for the generation of nitroformonitrile oxide (NFNO) were proposed, namely, by dehydration of dinitromethane and by nitration of 2-methyl-1-nitro-1-propene. NFNO was identified as its cyclodimerization product, dinitrofuroxan.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 722–726, April, 1995.     

Zum Hydratisierungs- und Dehydratisierungsverhalten von Magnesiumhydrogensulfat

On the Hydration and Dehydration Behaviour of Magnesium Hydrogensulfate Mg(HSO₄)₂ · H₂O has been prepared by crystallization from diluted sulfuric acid. The thermal destruction leads to the formation of siccative Mg(HSO₄)₂. This process is reversible, i. e., Mg(HSO₄)₂ rehydrates during cooling under formation of Mg(HSO₄)₂. H₂O. Due to further water reception Mg(HSO₄)₂ · H₂O decomposes at a temperature of 50°C forming Kieserite (MgSO₄ · H₂), MgSO₄ · 1,25H₂O, sulfuric acid, and water. During gentle warming of this heterogenous phase mixture it reacts under reconstruction of Mg(HSO₄)₂ · H₂O. The thermal measurements have been carried out in dynamic as well as in static gas atmosphere. The strong dependence of the decomposition temperatures from the partial pressure of the gaseous products could be demonstrated by in situ X-ray measurements.     

An Efficient and Mild Preparation of Vinyl Diazo Carbonyl Compounds

The combination of (CF3CO)2O/Et3N is found to be a mild and efficient dehydration condition for β-hydroxy-α-diazo compounds.     

The effect of water vapour pressure on the thermal dehydration of yttrium formate dihydrate

The kinetics of the thermal dehydration of yttrium formate dihydrate was studied by means of isothermal gravimetry under various water vapour pressures from 5×10^–4 to 8 torr. On the whole, the dehydration was described as the three dimensional phase boundary reaction, R₃. An unusual dependence of the rate of dehydration on the atmospheric water vapour pressure was observed: with increasing water vapour pressure, the rate increased at first, passed through a maximum, and then decreased gradually to a constant value. These phenomena were similar to the Smith-Topley effect. The mechanism of the phenomena can be described on the basis of the crystallinity of the dehydrated product phase.The authors wish to thank Mr. H. Minagawa of the Analytical Instrument Laboratory of Niigata University, for the X-ray diffraction measurements at high temperatures, and Mr. K. Hirata for help in the experimental work.     

The Thermal Decomposition of Fe(NO3)3·9H2O

Using thermogravimetric analyses as well as isothermal gravimetric measurements, the thermal stability of the iron(III) nitrate nanohydrate has been determined. Several decomposition stages are the result of melting, evaporation and hydrolysis processes occurring in the salt—water system in the temperature range of 20–400°C. Some of the intermediates and the final product (-Fe₂O₃) are characterized by means of chemical analyses, X-ray diffraction patterns and IR spectra.This revised version was published online in November 2005 with corrections to the Cover Date.     

膜分离天然气脱水蒸汽技术的研究现状

天然气脱水蒸汽是天然气净化过程中的必要环节,选择合适的脱水蒸汽技术和工艺至关重要。本文首先简要概述了新兴的膜分离天然气脱水蒸汽方法的特点,然后介绍了膜分离性能的表征参数及测试、膜组件设计及操作条件的选择,重点介绍了近年来膜分离甲烷脱水蒸汽技术中的聚合物膜材料、沸石分子筛膜材料,最后展望了金属有机骨架材料的应用潜力以及天然气脱水蒸汽技术未来的发展趋势。     

TG-DTA determination of water evolved from CaSO4·xH2O

To improve the separation of the dihydrate and hemihydrate phases, different sample masses, heating rates and crucibles were used. A TG-DTA method was developed for the determination of water evolved from CaSO₄·_xH₂O. The new crucible introduced for the Q-1500D MOM derivatograph gives a possibility for the evolved water to be determined independently from the TG and DTA curves.I am very grateful to Prof. Pelovski for the opportunity to use the Gypsum & Lime collection. This study was supported by the National Fund Science Research-Bulgaria.     

Synthesis of furoxan derivatives based on 4-aminofuroxan-3-carboxylic acid azide

A convenient preparative method was developed for the synthesis of 4-amino-3-furoxancarboxylic acid azide, which is a universal synthon for the preparation of functional furoxan derivatives. This method was used for preparing new azo-, azoxy-, azido-, cyano-, nitro-, carbonylamino-, and hydroxylamino-substituted furoxan derivatives, which have earlier been difficultly accessible.     

生物乙醇催化脱水制乙烯的研究进展

阐述了利用生物质能源的重要性,介绍了生物乙醇催化脱水制乙烯的发展现状,特别是其催化剂的研究状况。针对乙醇脱水制乙烯催化剂存在的问题,提出当前催化剂的发展趋势。