用∑WESH图评价某涂料化工厂的可持续性

介绍了在清洁生产过程中用∑WESH图评价涂料化工厂的可持续发展的原理及方法,并进行了一个实例的评价.从该厂的∑WESH图得出该厂的水及能源的利用率高,所用的原材料的稀缺性都不大,唯一较严重的问题是二甲苯的通过量大,危害性较严重.因此建议该厂在配方上尽量减少二甲苯的使用,开发新产品.     

喷涂前处理污染源的分析及其处理措施

随着我国国民经济的快速发展和国家"节能减排"重点项目的深入开展,各种污染源的分析及其处理措施的研究备受关注.本文在充分研究若干家电企业的钢铁喷涂制件的前处理工艺(如:预脱脂、脱脂、清洗、表调、磷化等)的基础上,分析喷涂前处理过程中的污染源,研究污染源的处理措施.     

酿酒酵母细胞表达异源萜类化合物的研究进展

萜类化合物具有可观的经济价值,但是目前的生产过程复杂、产量低。酿酒酵母甲羟戊酸途径为萜类化合物的合成提供直接前体,因此酿酒酵母细胞具有合成异源萜类化合物的天然优势。对酿酒酵母甲羟戊酸途径的清晰认识是对其进行有效利用的基础,本文从代谢途径、关键酶的特点和全局调控机制3个方面对该途径进行了介绍。从代谢途径的构建和优化、模块与底盘细胞的适配、模块构建及组装方式的角度概述了酿酒酵母细胞异源合成单萜、倍半烯萜、二萜、三萜类化合物的研究进展。指出实现酿酒酵母高效合成萜类化合物所需要解决的基础问题是对酿酒酵母甲羟戊酸途径进行更为全面了解和对萜类化合物的天然代谢途径进行明确解析;另外,合成生物学的进一步发展也将为此提供应用基础。     

香叶油的研究进展

为了全面了解香叶油的研究现状,为我国香叶油的开发利用提供思路, 综述了香叶的栽培、组培技术研究、香叶油的应用、香叶油的提取及化学成分研究、香叶油调配研究等方面的现状,并对香叶品种的遗传改良提出一些有益的建议.     

胶原纤维的性能特点和作用

1胶原纤维巴西Novaprom胶原纤维是以精选的牛皮内剖层(真皮)组织提取的,它不同于明胶或明胶的衍生物。它的生产是在严格控制的时间和温度范围内进行的,从而确保其主要成分──胶原蛋白的活性不变,并以天然纤维的形式存在。它在肉制品中的结构呈纤维状而不是一般的胶冻,因而这种结构是非常稳定的,是不可逆的。它是很好的功能性动物纤维蛋白,在肉制品及鱼糜制品等相关的食品中得到广泛的应用。2胶原纤维的性能及相关指标(1)蛋白质含量:胶原纤维中的动物蛋白质(M×6.25)高达98%,含有人体必需的氨基酸。(2)吸水、持水性:胶原纤维结构良好,呈矩…     

鲜为人知的科学珍闻

有言在先,珍闻的挑选奉行以下原则:科学应该是有趣的,科学之所以好玩,部分原因在于你了解、知道这些奇谈怪论的存在。科学的伟大之处在于,它不必是教条的、有价值的实验,也不要求对所有理论进行最准确的过滤以得     

玻璃纤维拉丝池窑配合料设备研制的进展

玻璃纤维池窑拉丝生产线配合料的制备中,原料是形成优质玻璃液的基础,因此可以说配合料的稳定性、均匀性和准确性对玻璃纤维的质量起着决定的作用.生产实践证明:组分和粒度均匀的配合料,不但能强化玻璃液的熔化和澄清过程,而且还能减少或消除影响玻璃质量的各种弊病.所以认真拟定玻璃纤维原料的成分和选择玻璃纤维的种类和化学性质:严格控制进厂原料化学成分、粒度和水份;做好原料的分堆、存放、加工、称量、混合、输送是优质配合料制备不可缺少的手段,这也是做好玻璃纤维池窑配合料的基本任务.     

氢氧化镁阻燃剂的研究进展

主要论述了国内外阻燃剂的种类和发展,指出由于环境和健康的原因,无机阻燃剂是最有发展前途的,其中的氢氧化镁因其特有的性质,在无机阻燃剂中尤为突出.考虑到氢氧化镁的广泛应用的前景和其本身的缺点,对其改性成为业界的研究重点,其中主要介绍了钛酸酯、硬脂酸(盐)、镁盐晶须和胶囊化等技术,指出以后的发展方向是在改性基础上的协同作用.     

高浸透性大分子聚酯乳液的研制

1前言 随着池窑生产的发展,原有的浸润剂在快速浸润性和快速浸透性方面无法得到满足.意大利DSM公司聚酯乳液是公认的喷射纱浸润剂最好的成膜剂.本项目的目的是研制出能工业化生产的与DSM公司产品质量相当的聚酯乳液,替代进口,节约外汇,满足我国池窑发展需要,争创良好的经济社会效益.     

宁静——使艺术深华

宁静的山是心灵的绘画,宁静的水是灵魂的诗篇,宁静的夜是精神的书籍。在这越来越充斥着物欲纵横的社会,浮躁成了现代人的代名词,而保持一颗宁静的心,尤其在艺术创作中显得尤为重要。     

New spirodilactam polymers

New polyether and poly(ether ketone)s containing the rigid 1,6-diazaspiro[4.4]nonane-2,7-dione (spirodilactam) core in the backbone are described. The polymers are soluble in common solvents from which clear, colorless films are readily cast. Excellent thermo-oxidative stability is shown by all of the systems studied with TGA stabilities up to 595 °C or 598 °C in air and argon respectively. Dielectric constants ranged from 2.53 to 3.00 and water absorption results were nil to 3.6%.     

Stereoselective reduction of (±)-bicyclo[3.3.1]nonane-2,6-dione by microorganisms

The biotransformation of (±)-bicyclo[3.3.1]nonane-2,6-dione by Aspergillus niger and Glomerella cingulata was investigated. The diketone was reduced to the ketoalcohol 2-endo-hydroxy-bicyclo[3.3.1]nonane-6-one and the diol endo,endo-bicyclo[3.3.1]nonane-2,6-diol respectively. Endo,endo-bicyclo[3.3.1]nonane-2,6-diol and ketoalcohols produced by G. cingulata had high optical purity, on the other hand, reduction by A. niger yielded optically active (-)-(1R, 2S, 5R, 6S)-bicyclo[3.3.1]nonane-2,6-diol(99·9% e.e.). © 1998 SCI     

Reactions with β-ketodianilides. I. New synthesis of Pyrido[3,4-c]pyridine Derivatives

Acetonedicarboxylic acid dianiline reacted with malononitrile, ethyl cyanoacetate or benzoylacetonitrile to give (6-amino-5-cyano-1,2-dihydro-2-oxo-1-phenylpyrid-4-yl)-acetanilide ( 3 ), (3-cyano-2,6-dioxo-1-phenyl-1,2,5,6-tetrahydropyrid-4-yl)acetanilide ( 8 ) or (3-cyano-1,6-dihydro-1,2-diphenyl-6-oxopyrid-4-yl)acetanilide ( 9 ). Compounds 3 and 8 could be cyclised into 8-amino-1,6-diphenyl-1,2,4,5,6,7-hexahydro-7-iminopyrido[3,4-c]pyridine-2,5-dione ( 4 ) and 7-amino-1,2,3,5,6,8-hexahydro-1,6-diphenylpyrido[3,4-c]pyridine-2,5,8-trione ( 10 ) respectively by heating their solutions in dimethylformamide in the presence of triethylamine. Each of 3 and 4 coupled with arenediazonium chlorides to give the corresponding arylhydrazone derivatives ( 5a–d ) and ( 6a–c ), respectively. Condensation of 4 with p-nitrosodimethylaniline yielded 8-amino-4- (p-dimethylaminophenylimino)-1,6-diphenyl-1,2,4,5,6,7-hexahydro-7-iminopyrido[3,4-c]pyridine2,5-dione ( 7 ).     

Design,synthesis, antibacterial and antifungal activity of novel spiro-isoxazolyl bis-[5,5′]thiazolidin-4-ones and spiro-isoxazolyl thiazolidin-4-one-[5,5′]-1,2-4 oxdiazolines

The synthesis of novel isoxazolyl 1,6-dithia-4,9-diazaspiro[4.4]nonane-3,8-diones (4a–h) and isoxazolyl 1-oxa-6-thia-2,4,9-triazaspiro[4.4]non-2-ene-8-ones (5a–h) analogs is described. Reaction of N-1-\{3-methyl-5-[(E)-2-aryl-1-ethenyl]-4-isoxazolyl}-2-chloroacetamide (2) with aryl isothiocyanates yielded 3,3-methyl-5-[(E)-2-aryl-1-ethenyl]-4-isoxazolyl-2-(arylimino)-1,3-thiazolan-4-ones (3). Cyclocondensation of 3 with mercaptoacetic acid furnished novel isoxazolyl-1,6-dithia-4,9-diazaspiro[4.4]nonane-3,8-diones (4a–h). Cycloaddition of 3 with benzonitrile oxides afforded novel isoxazolyl 1-oxa-6-thia-2,4,9-triazaspiro[4.4]non-2-ene-8-ones (5a–h). Compounds 4a–h and 5a–h showed significant biological activity against all the standard strains.     

A Practical Asymmetric Synthesis of Enantiopure Spiro[4,4]nonane‐1,6‐dione

A practical asymmetric synthesis of enantiopure spiro[4,4]nonane‐1,6‐dione, a valuable precursor for chiral ligand development, is reported. This synthetic strategy includes a kinetic resolution of the readily synthesized ketone precursor with a chiral quaternary carbon center by bioreduction with baker’s yeast as the key step, followed by a hydroformylation, oxidation, esterification and Dieckmann cyclization reaction sequence to generate the spiro five‐membered ring. It was found that the masking of the β‐ketone carbonyl group of enantiopure ethyl 1‐allyl‐2‐oxocyclopentanecarboxylate via formation of a ketal with 1,3‐diol derivative is necessary during the process of Dieckmann condensation in order to prevent its racemization under basic conditions. This method allows the gram‐scale preparation of both enantiomers of spiro[4,4]nonane‐1,6‐dione ( 1 ) with excellent enantiopurities (up to >99% ee) in the overall yields of 54% [(R)‐ 1 ] and 42% [(S)‐ 1 ], respectively. The practicality of the present synthetic procedure has provided a fundamental platform for the development of spiro[4,4]nonane‐1,6‐dione‐based chiral chemistry.     

One-Pot Four-Component Synthesis of 5,10-Diarylpyrido[4,3-b][1,6] Naphthyridine Derivatives in Ionic Liquids Catalyzed by TsOH

A one-pot four-component reaction of aldehyde, aromatic amine, and two equivalents of piperidine-2,4-dione was treated in ionic liquids of [BMIm]Br catalyzed by TsOH (p-toluenesulfonic acid), and gave a series of 5,10-diarylpyrido[4,3-b][1,6]naphthyridine derivatives in good yields. This procedure has the advantages of mild reaction conditions, good yields, one-pot, and environmentally benign.     

3-Methylnonane-2,4-dione – An Intense Odour Compound Formed during Flavour Reversion of Soya-Bean Oil

Nonane-2,4-dione and 3-mehthylnonane-2,4-dione were identified in reverted soya-bean oil. The odour threshold of the latter compound, which smelled “lard-like, strawy, fruity”, was very low (0.01 ng/1 air) in comparison to that of the nonane-2,4-dione (3.9ng/1 air). Based on its odour properties and the result of an aroma extract dilution analysis, which have been recently reported (Fat Sci. Technol. 90 , 332 [1988]), it was concluded that 3-methylnonane-2,4-dione contributed very strongly to the reversion odour of soya-bean oil. 3-Methylnonane-2,4-dione, 3,7-dimethyloctane-2,4-dione, decane-2,5-, -3,5-and- -4,5-dione, 3-oxo- and 5-oxodecanal were prepared as reference for the identification experiments. The spectroscopic (1H-NMR, MS) and odour threshold data are reported.     

Green Synthesis of Fused Polycyclic Pyrazolo[3,4-b][1,6]naphthyridine Derivatives in Ionic Liquids via Three-Component Reaction

A green synthesis of fused polycyclic 4-aryl-3-methyl-1-phenyl-7,8-dihydro- 1H-pyrazolo[3,4-b][1,6]naphthyridin-5(4H)-one derivatives is described in ionic liquids. Under the protection of nitrogen, this three-component reaction including aromatic aldehyde, 3-methyl-1-phenyl-1H-pyrazol-5-amine, and piperidine-2,4-dione gives un-aromatized products in high yields. This new procedure to pyrazolonaphthyridines has the advantages of one pot reaction, milder reaction conditions, high yields, and is environmentally benign.     

New degradable thermosets obtained by cationic copolymerization of DGEBA with an s(γ-butyrolactone)

Diglycidylether of bisphenol A (DGEBA) was cured with different proportions of 1,6-dioxaspiro[4.4]nonane-2,7-dione (s(γ-BL)) with ytterbium triflate as initiator. The curing was studied with differential scanning calorimetry (DSC) and Fourier transform infrared in the attenuated total reflection mode (FTIR/ATR). FTIR/ATR was used to monitor the competitive reactive processes and to quantify the conversion of the epoxide, lactone and intermediate spiroorthoester (SOE) groups. The shrinkage undergone during curing was monitored by means of thermomechanical analysis (TMA). By combining the results obtained by FTIR/ATR and TMA, the processes that were and were not responsible for shrinkage were identified. The thermal and dynamic mechanical properties of the cured materials were determined by DSC and by dynamic mechanical thermal analysis (DMTA), respectively. The kinetic triplet associated with calorimetric curing was determined by means of isoconversional analysis. An increase in the proportion of lactone results in an increased curing rate, a decrease in shrinkage after gelation and a decrease in the glass transition temperature (T_g). Finally, as a preliminary measure, we examined the potential of the systems studied as reworkable materials by means of hydrolytic and thermal degradation. An increase in the ester units in the network results in materials that are less thermally stable and whose controlled degradability is greater.     

（3aS,6aR）-1,3-二苄基-四氢-4H-噻吩并[3,4-d]咪唑-2,4-二酮（1H）制备工艺优化

d-生物素的重要中间体：（3aS,6aR）-1,3-二苄基-四氢-4H-噻吩并[3,4-d]咪唑-2,4-二酮（1H）（以下简称硫代内酯）由（3aS,6aR）-1,3-二苄基-四氢-4H-呋喃并[3,4-d]咪唑-2,4-二酮（1H）（以下简称内酯）中呋喃环上的氧用硫取代而成。目前常用的硫代工艺均有一些明显的弊端,本文对硫代工艺进行改进,可以提高硫代反应的收率和产物的质量。