AMMONIA CATALYZED ORGANOSOLV DELIGNIFICATION OF POPLAR

A parametric investigation of NH₄OH catalyzed solvent delignification of poplar was conducted to define pretreatment conditions which would yield an optimal separation of the biomass components and an enzymatic susceptible solid carbohydrate phase. Delignification parameters of interest included concentration of NH₄OH, time and temperature of the reaction, and type of solvent. The addition of 0.82 M NH₄OH to the delignification liquor increased lignin removal and decreased carbohydrate degradation, but increasing NH₄OH concentration had no additional effect. At lower reaction temperatures, the extent of delignification increased with reaction time; at higher temperatures, a “relignification” of the pretreated wood was observed. The delignification and hemicellulose solubilization were modelled and rate constants reported. No major difference between three potential pulping solvents—ethanol, butanol, phenol—was observed. The enzymatic susceptibility of pretreated wood samples was approximately 6-fold greater than that of the untreated poplar. UV absorbance was used to qualitatively characterize the soiubilized lignins.     

Preparation and properties of polyamines. Part I. Polymers containing dinitro substituted aromatic groups

Relatively high molecular weight polyamines with aromatic nitro groups in the repeat units were prepared by the reactions of aliphatic diamines, and 1,5-difluoro-2,4-dinitrobenzene, at elevated temperatures in diphenyl sulfone. The physical characteristics, including solubility, thermal stability, and viscosity of the resulting polyamines were found to be strongly dependent on the aliphatic chain length of the diamines used. All polymers exhibited exceptional solvent resistance. Except for strong acids with bulky counter-ions, including sulfuric, perchloric, and nitric acids, the polymers were found to be insoluble in all common organic solvents at room temperature.     

甲基异丁基酮-甲乙酮脱蜡脱油生产微晶蜡工艺研究

介绍了以甲基异丁基酮(MIBK)和甲乙酮(MEK)为溶剂进行脱蜡脱油生产微晶蜡的试验研究，对溶剂脱蜡脱油过程的各种工艺条件进行了考察。结果表明，与采用常规溶剂的过程相比，其过滤速度和微晶蜡产品的收率都得到提高，而且微晶蜡的含油量达到小于1％的食品级标准要求。MIBK—MEK拥有的良好的选择性使其在溶剂脱蜡脱油生产微晶蜡工艺中有较好的应用前景。     

A theoretical study of solvent effects on Kolbe-Schmitt reaction kinetics

A theoretical DFT study was employed to confirm the Kolbe-Schmitt reaction mechanism and investigate solvent effects on this reaction. The use of a solvent in the Kolbe-Schmitt reaction is desirable to facilitate a homogeneous reaction mixture and potentially improve the reaction rate. The candidate solvents were designed using computer aided molecular design (CAMD) and tested using DFT solvation calculations. The results from the quantum mechanical calculations were then used to determine the rate constants for each elementary step, the overall reaction yields and the corresponding residence time. The methodology was tested on the reaction without solvent, with solvents reported in the literature, and with the designed solvents. The study revealed that in the presence of solvents with high dielectric constant the reaction becomes reversible, leading to low product yields.     

Effect of sample size on solvent extraction for detecting cocontinuity in polymer blends

The effect of sample size on the results of solvent extraction measurements for detecting cocontinuity in polymer blends was investigated. Poly(ethylene oxide)/polystyrene (PEO/PS) blend samples of several thicknesses were analyzed by removing the PEO phase using water extraction. The experimental degree of continuity was shown to have a linear dependence on the reciprocal of sample thickness. A model is proposed to explain this dependence and to allow the bulk or true degree of continuity to be determined. Measurement of the bulk degree of continuity is useful for understanding properties of cocontinuous polymer blends such as electrical conductivity, impact strength, or tensile strength.     

Solvent free liquid phase oxidation of benzyl alcohol using Au supported catalysts prepared using a sol immobilization technique

Solvent free oxidation of benzyl alcohol was investigated in the absence of a base using Au catalysts prepared by sol immobilization on titania and carbon supports. Comparison between the Au supported catalysts revealed that activity and distribution of products was dependent on the nature of support and heat treatment. Specifically, heat pre-treatment of the Au catalysts has a beneficial effect in terms of activity, but is detrimental in terms of selectivity to the benzaldehyde. We conclude that sol immobilization is a suitable technique for preparing gold catalysts with small particle size and narrow particle size distributions and very high activity and selectivity for benzyl alcohol oxidation.     

锝萃取型发生器萃取锝初探

锝萃取型发生器技术是采用溶剂萃取的方法生产^99Tc^m。对锝萃取工艺条件进行了初步研究。由于锝与铼有相似的化学性质,实验中研究了在碱性体系中甲乙酮对铼的萃取行为,考察了萃取剂用量、碱液浓度、铼的浓度及水相中铝浓度对萃取铼的影响,在此基础上进行了^99Tc^m的示踪实验,实验结果表明：甲乙酮对^99Tc^m萃取率达99％。     

Solvent free oxidation of alcohols catalyzed by KMnO4 adsorbed on Kieselguhr

Efficient and selective oxidation of primary and secondary alcohols to the corresponding aldehydes and ketones catalyzed by potassium permanganate supported on Kieselguhr reagent under solvent free conditions are reported.     

功能化磁性微球对溶剂绿7的吸附性能研究

为了有效地去除工业染料废水中的有机染料,本文以水热合成法制备出Fe3O4纳米微球,并将其表面包覆功能化外壳,得到新型的磁性吸附剂.并详细讨论了温度、浓度、pH等因素对染料吸附效果的影响.实验结果表明,吸附剂对溶剂绿7具有较好的吸附能力,随着染料浓度的增大,吸附量显著增大,溶液的温度升高,吸附量降低;较低的pH有助于吸附作用的发生,当pH=2时,脱色率达到95%.鉴于此新型磁性吸附剂良好的吸附性能及低廉的制备成本,很有潜力应用于工业印染废水的脱色处理中.     

溶剂萃取法从废电子元件中回收钯

用溶剂萃取法从硝酸浸取液中提取Pd~(2+)与Cu~(2+),Ni~(2+).N_(235)作Pd~(2+)的萃取剂,煤油作稀释剂,癸醇作调相剂,最佳工艺条件是萃取剂组成,25%N_(235)—10%癸醇—65%煤油;硝酸浓度,0.5～3mol/L;温度,室温;1.5mol/L HNO_2作负载有机相杂质离子Ni~(2+),Cu~(2+)的洗涤剂,其一次洗涤率近100%;6%硫脲,或5%氨水作负载有机相中Pd~(2+)的反萃剂,其一次反萃率分别为98.6%,68.5%.