水作反应介质的绿色化学技术

综述了水相中的各种有机合成反应技术、生物催化反应技术、催化剂的回收和产品分离技术以及水相反应中电化学和太阳能化学技术,并对水作反应介质的绿色化学技术在化工中的应用和发展进行了展望.     

绿色化学研究进展

对绿色化学在新型催化剂和反应介质方面的研究进展进行了综述。新型催化剂主要包括固体酸催化剂、固体碱催化剂、金属催化剂等。这些催化剂不仅具有较高的活性和选择性,而且催化剂和反应体系易于分离。新型反应介质主要包括超临界流体和离子液体,它不仅可以替代传统的有毒有害的挥发性有机溶剂,同时可以提高反应的活性和选择性,并且易于回收利用。高效催化剂和绿色反应介质的研究开发是未来绿色化学的重要研究内容。     

水介质中的有机合成反应

本文介绍了在水介质中进行并为水促进的几类有机合成反应的研究进展。由于其成本低廉,没有污染,在工业合成中具有广阔前景。     

以绿色化学理念 改进沉淀反应实验

绿色化学是对传统化学思维的创新与发展，是更高层次的化学。本文以绿色化学理念对沉淀反应实验从试剂的选用、用量及实验安排等方面进行了研究与改进，实践证明，改进后的实验，不仅从源头防止了污染，使试剂能充分、合理的利用，而且实验现象明显、效果好。     

水处理中的绿色化学与绿色技术

探讨了绿色技术的定义并对有代表性的水处理技术进行了评价 ,认为绿色技术应当定义为能够同时满足技术经济指标先进、无毒和不污染环境等 3项基本要求的技术。目前正在研究开发的高级氧化技术、电催化氧化法、超临界水氧化法、超声波降解技术及膜处理技术虽然尚有不够完善之处 ,但可认为是绿色水处理技术。化学法是否是绿色技术 ,关键要看所使用的产品是否符合绿色化学的要求。理想的绿色技术是零排污技术 ,零排污水处理技术代表了 2 1世纪水处理技术的发展方向     

绿色化学技术在环境污染治理中的应用

论述了绿色化学的原理、研究现状,总结了绿色化学技术的应用进展。从大气污染、水污染和固体废物三方面论述了绿色化学技术在环境污染治理中的应用情况,并提出应用绿色化学技术来解决环境污染问题是环境保护的发展方向。工业、农业、日常生活等采用无毒、无害并可循环使用的物料,化学反应的绿色化,是从“本”治理环境污染的重要途径。     

绿色化学发展及相关技术分析

绿色化学是当前化工和化学研究的发展方向,对于现代工业的发展有非常重要的作用,对于化学技术以及化工产业发展也具有良好的作用.对绿色化学及其技术发展进行了分析,阐述了绿色化学的含义,并总结了当前绿色化学技术及其相关应用,探讨了绿色化学技术发展的趋势.     

新型绿色Knoevenagel反应进展

Knoevenagel反应在有机化学中是很重要的一类缩合反应,能够在活泼亚甲基和羰基之间脱水形成碳碳双键,广泛应用于合成以及一锅法串联反应,在过去一直是有机化学家研究的热点。发展至今,很多关于Knoevenagel反应的研究都已经打破了传统有机化学的实验形式和反应条件。针对最近新发展的,符合绿色化学要求的新型Knoevenagel反应进行简单介绍。     

绿色化学在有机化学化工中的应用进展

主要介绍了近年来引起人们关注的包括原子经济性、手性合成、环境友好的“洁净”的反应介质等一些绿色化学的基本原理和概念在有机化学化工中的应用进展。     

Supercritical carbon dioxide as a green reaction medium for catalysis

Carbon dioxide in its liquid or supercritical state (scCO(2)) has a prodigious potential as an environmentally benign reaction medium for sustainable chemical synthesis. Since the mid-1990s, rapidly increasing research efforts have shown that scCO(2) can replace conventional and potentially hazardous solvents in a wide range of processes. There is also increasing evidence that the application of scCO(2) can broaden the scope of catalytic synthetic methodologies. On the basis of the experience in our laboratories, this report analyzes the impact of scCO(2) on green organometallic catalysis.     

Applicability of supercritical water as a reaction medium for desulfurisation and demetallisation of gasoil

In this study, the potential of supercritical water (SCW) was investigated, to remove sulfur and metals from gasoil, either separately or simultaneously. The experiments were carried out in a stirred batch autoclave at 673 K and 25 MPa, using a standard hydrotreated gasoil spiked with different sulfur-, nickel- and vanadium-containing model compounds. The results show that only non-aromatic sulfur compounds will react in SCW. The observed degree of desulfurisation is marginal. Aromatic sulfur compounds are too stable and will not react. Demetallisation of selected metal complexes was not observed. The metal complexes undergo some rearrangements in SCW, but their basic structure remains intact. Desulfurisation and demetallisation were only observed in the presence of a conventional hydrotreating catalyst. Concluding, SCW alone is not a suitable reaction medium for desulfurisation and/or demetallisation of gasoil. This conclusion is supported by thermodynamical calculations.     

Detailed reaction engineering as a basis of modern slurry technology for PE-HD-production

Saving product quality and quality consistency in polymer production needs a detailed knowledge of the polymerization process. A process model for the slurry polymerization of ethylene with high mileage Ziegler-catalyst/cocatalyst systems has been developed. This model teaches which set of process parameters must be kept constant together with their acceptable deviations to keep product data within the required frame. The consequences for a technical production plant are also discussed.     

High internal phase emulsion as reaction medium for precipitating brushite crystals

This present work was aimed at fabrication of brushite crystals using oil-in-water high internal phase emulsion as a reaction medium. The oil phase of more than 75 wt.% was dispersed in the continuous aqueous phase. Due to the high oil volume fraction, the oil droplets were no longer spherical but were squeezed to take the shape of polyhedral. The morphology of the crystals was influenced by the structure of the emulsion and precursor concentration. The crystals were subjected to cytotoxicity test to ensure their compatibility with synoviocytes, which are cells that line the knee joints of rabbits. The crystals were able to sustain the cells for 5 days, which manifest their potential as osteoconductive coatings.     

绿色水处理剂聚天冬氨酸的研究进展

根据采用原料的不同总结了制备聚天冬氨酸（polyaspartic acid，以下简称PASP）的不同路线及方法，介绍了PASP的结构和降解性能以及其阻垢性能和相对分子质量之间的关系。并且从微观角度阐述了PASP与水形沉积物碳酸钙、磷酸钙和硫酸钡之间的作用情况，从而解释了PASP对三种矿物质在水溶液中成核及结垢过程中的影响行为。最后提出了有待进一步研究的一些问题。     

Modified polyacrylonitrile fiber as a renewable heterogeneous base catalyst for Henry reaction and Gewald reaction in water

A polyacrylonitrile fiber catalyst with high polar surface micro‐environment (C‐PANF‐Na) was conveniently synthesized and characterized by elemental analysis, Fourier‐transfer infrared spectroscopy, UV–vis spectroscopy, scanning electron microscopy, X‐ray diffraction, and breaking strength test. The catalytic performance of the fiber was tested by Henry reaction and Gewald reaction in water and favorable results were obtained in terms of high yields, mild conditions, extensive applicability, superior catalytic recyclability, and renewability. It also has advantages of easy preparation, high functional degree, good stability in acid and base, high strength, and good flexibility, and so on. In addition, a high solvent selectivity phenomenon was found in this catalytic system and the reason was explained by proposing a high polar micro‐environment effect. Furthermore, the fiber catalyst performed well in scaled‐up experiment and flow chemistry experiment, which shows tremendous potential in industrial catalyst as an ideal material for packed bed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45992.     

Linear-dendritic block copolymers as a green scale inhibitor for calcium carbonate in cooling water systems

Water-soluble monomer APEG-PG-(OH)n were produced and the Structure of APEG-PG-(OH)5 were identified by ¹H-NMR. APEG-PG-(OH)n were copolymerized with maleic anhydride (MA) to synthesize no phosphate and nitrogen free calcium carbonate inhibitor MA/APEG-PG-(OH)n. The structure and thermal property of MA/APEG-PG-(OH)5 were characterized and measured by ¹H-NMR, GPC and TGA. The observation shows that the dosage and n value of MA/APEG-PG-(OH)n plays an important role on CaCO₃ inhibition. MA/APEG-PG-(OH)5 displays superior ability to inhibit the precipitation of calcium carbonate, with approximately 97% inhibition at a level of 8 mg/L. The effect on formation of CaCO₃ was investigated with combination of SEM and XRD analysis.     

Pyrolysis of 1,3-butanediol as a model reaction for wood liquefaction in supercritical water

1, 3-Butanediol was pyrolyzed at 425°C in a batch reactor as a model system for liquefaction of lignocellulosic materials such as wood. The observed gas and liquid products were consistent with fragmentation, dehydration, and condensation/polymerization reaction pathways. Reaction in supercritical water altered the selectivity of the reactions to give mainly propene and formaldehyde. Dehydration and the formation of two-carbon products were suppressed by water. The conversion of 1, 3-butanediol in dilute aqueous solutions increased three to four fold when the reaction density was increased by 33%. Trace oxygen was an important inhibitor, particularly in the dilute solution, but had only a minor effect on the reaction selectivity.     

Model for the propagation of a stationary reaction front in a viscoelastic medium

A coupled thermomechanical model for the propagation of a stationary chemical-reaction wave in a condensed medium is developed. Stresses and strains that arise during the reaction as a result of thermal and “concentration” expansion of the material are related by Maxwell’s equations for a viscoelastic medium. The expression for the heat flux is written as a generalized Fourier law with finite relaxation time for the heat flux. It is shown that deformation of the material in the reaction zone can lead to an apparent change in the activation energy, heat effect, and other characteristics of the system. This model allows for the existence of two different — subsonic and supersonic — regimes of propagation of the front, as well as the model in which the stress- and strain-tensor components are related by a generalized Hooke’s law. Translated fromFizika Goreniya i Vzryva, Vol. 36, No. 4. pp. 41–51, July–August, 2000.