Synthesis and Characterization of Thermally Stable Lignosulfonamides

Lignin, a highly aromatic macromolecule building plant cells, and cellulose are two of the most commonly occurring natural polymers. Lignosulfonate is a grade of technical lignin, obtained as a by-product in the paper and wood pulping industries, a result of the used lignin isolation method, i.e., sulfite process. In this work, sodium lignosulfonate is used as a starting material to manufacture sulfonamide derivatives of lignin in a two-step modification procedure. Since this direction of the lignin modification is rather rarely investigated and discussed, it makes a good starting point to expand the state of knowledge and explore the properties of lignosulfonamides. Materials obtained after modification underwent characterization by FTIR, SS-NMR, WAXD, SEM, and TGA. Spectroscopic measurements confirmed the incorporation of dihexylamine into the lignin structure and the formation of lignosulfonamide. The crystalline structure of the material was not affected by the modification procedure, as evidenced by the WAXD, with only minute morphological changes of the surface visible on the SEM imaging. The obtained materials were characterized by improved parameters of thermal stability in relation to the raw material. As-prepared sulfonamide lignin derivatives with a potential application as a filler in biopolymeric composites may become a new class of functional, value-added, sustainable additives.     

耐高温磺化聚苯并咪唑的合成与表征

用不同配比的5-磺酸钠间苯二甲酸、4,4'-二羧基二苯醚与3,3'-二氨基联苯胺在多聚磷酸中进行共缩聚反应,制得了一系列磺化度可控的溶解性较好的磺化聚苯并咪唑(sPBI-IE).采用FTIR,¹HNMR,GPC和TGA等手段对所合成的聚合物的结构、分子量与热稳定性能进行了表征.结果表明,sPBI-IE的数均分子量(M_n)介于41300-46900之间,多分散指数为2.15-2.54,并且sPBI-IE具有优异的热稳定性能,其起始分解温度、最大分解速率温度、5%和10%热失重温度分别高于513,586,573和597℃.     

An Expeditious Synthesis of ALK-2-YN-1-OLS

A convenient inexpensive preparation of alk-2-yn-1-ols, commencing from terminal alkynes, has been developed. This procedure allows for using paraformaldehyde instead of gaseous formaldehyde for hydroxymethylation of alk-1-ynylmagnesium bromides.     

耐高温含氟磺化聚苯并咪唑的合成及表征

采用5-磺酸钠间苯二甲酸、双(苯甲酸)六氟丙烷与3,3',4,4'-四氨基联苯在多聚磷酸中通过共缩聚反应, 合成了一系列磺化度(定义为100个重复单元中所含的磺酸基个数, SD)可控的含氟磺化聚苯并咪唑(sPBI), 并利用红外光谱、核磁共振、凝胶色谱和热失重分析等手段对其结构、分子量与热稳定性进行了表征, 还考察了其溶解性和成膜性. 结果表明, sPBI的数均分子量(M_n)为61300～86000, 多分散指数介于1.96～2.34之间, 并且sPBI具有良好的成膜性和优异的热稳定性能, 其5%和10%热失重对应温度均随着SD的增加而有所提高, 在SD为70%时分别为549和576 ℃. 此类聚合物在质子交换膜材料方面具有一定的应用前景.     

Synthesis of Thermally Stable MCM-41 at Ambient Temperature

A new process to synthesize thermally stable mesoporous molecular sieves of MCM-41 structure based on delayed neutralization at ambient temperature was investigated. All samples synthesized by this new method have BET surface areas of about 1100m²/g and possess high thermal stability up to 900°C. Higher crystallinity and less lattice constriction after calcination were observed for samples with a longer aging period. Those samples with aging time longer than 10 days exhibited four characteristic XRD peaks of MCM-41 both before and after calcination at 560°C. The N₂ adsorption-desorption isotherms of the calcined samples showed larger average pore size and more homogenous pore size distribution. The method was also successfully applied to the synthesis of MCM-41 with different surfactants of hydrocarbon length with 10–18 carbons and proves to be a simple route for obtaining thermally stable MCM-41 at room temperature.     

Efficient Synthesis of Highly Functionalized,S -Alkyl 1-Alkyl-4,4-dimethyl-2,5-dioxo-pyrrolidine-3-carbothioates

5-Isopropylidene-2,2-dimethyl-1,3-dioxane-4,6-dione (the condensation product of Meldrum's acid and acetone) reacts with alkyl isocyanides in the presence of this to produce S -alkyl 1-alkyl-4,4-dimethyl-2,5-dioxo-pyridine-3-carbothioates in good yield.     

缓冲体系中高热和水热稳定性的MCM-48介孔分子筛的合成

利用混合阳离子-非离子表面活性剂为模板剂在缓冲体系中成功地合成出具有高热和水热稳定性的MCM-48介孔材料. 通过XRD, N₂吸附-脱附, ²⁹Si MAS NMR和 ³¹P MAS NMR等手段对样品进行了表征. 结果表明, 合成的MCM-48材料具有高的比表面积和高度有序的孔道系统. 样品在空气中于900 ℃下焙烧15 h和在600 ℃ 100%水蒸气下处理8～10 h, 仍能保持良好的立方孔道结构, 显示很高的热稳定性和极好的水热稳定性.     

Synthesis of Thermally Stable Energetic 1,2,3‐Triazole Derivatives

Various thermally stable energetic polynitro‐aryl‐1,2,3‐triazoles have been synthesized through Cu‐catalyzed [3+2] cycloaddition reactions between their corresponding azides and alkynes, followed by nitration. These compounds were characterized by analytical and spectroscopic methods and the solid‐state structures of most of these compounds have been determined by using X‐ray diffraction techniques. Most of the polynitro‐bearing triazole derivatives decomposed within the range 142–319 °C and their heats of formation and crystal densities were determined from computational studies. By using the Kamlet–Jacobs empirical relation, their detonation velocities and pressures were calculated from their heats of formation and crystal densities. Most of these newly synthesized compounds exhibited high positive heats of formation, good thermal stabilities, reasonable densities, and acceptable detonation properties that were comparable to those of TNT.     

Photochemistry of 4,4-Dialkoxy-2,5-cyclohexadienones

Irradiation (λ > 370 nm) of 4,4-dimethoxy-2,5-cyclohexadienone ( 1 a ) in benzene affords mainly the ketene acetal 4 a , which then undergoes further rearrangement. The carbomethoxycyclopentenones 6 and 7 were isolated in modest yields (10–15°). It is conceivable that the latter results from decomposition of the unobserved bicyclohexenone 5 a , the formation of which could be expected by analogy to e.g. 1 c → 5 c . Compound 4 a is presumably formed via 1,2 hydrogen shift from the intermediate zwitterion 3 a . Under similar irradiation conditions 1,4-dioxa-spiro[4.5] deca-6,9-dien-8-one ( 1 b ) gave 4 b as the only definable product. In i-C₈H₁₈ 1 a gave p-methoxyphenol ( 8 ) as the only product, most probably via hydrogen abstraction.     

The rearrangement of 4,4-diphenylcyclohexa-2,5-dienylidene

Pyrolytic decomposition of the Li salt of the tosylhydrazone of 4,4-diphenyl-2,5-cyclohexadienone produces a mixture of biphenyl, o-terphenyl, p-terphenyl, methyl-o-terphenyl and the azine of 4,4-diphenyl-2,5-cyclohexadienone (13). Insight into the reaction pathway was provided by the pyrolytic decomposition of 2-deuterio tosylhydrazone 8a which generates o-terphenyl 10a and 10b in ratio of 69:31. These results are interpreted in terms of the carbene rearrangements of Schemes 2, 3 and 5.     

4,4＇-二硝基二苯乙烷(烯)的合成

二硝基二苯乙烯;硝基甲苯;氧化二聚反应;4;4＇-二硝基二苯乙烷(烯)的合成     

Synthesis of some 1-substituted 2,5-diphenylimidazoles

The synthesis of 1,2,5-triphenylimidazole derivatives was accomplished by reaction of -benzamidoacetophenone with primary aromatic amines in the presence of phosphorus trichloride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1264–1265, September, 1972.     

Synthesis and Chemistry of 2,5-Dimethylene-2,5-Dihydrofuran

2,5-Dimethylene-2,5-dihydrofuran (3), generated flash pyrolitically, underwent di- and trimerization reactions to give cyclic dimer and trimer. Compound 3 was trapped with methanol, ethanol, bromine, acetic acid, thiophenol and oxygen. Results from trapping experiments suggest that the diradical form of 3 is involved.     

Synthesis of 1-alkyl-3-arylamino-pyrrole-2,5-diones

Reaction of 1-alkyl-3-alkylaminopyrrole-2,5-diones with primary arylamine hydrochlorides in methanol or DMSO gives 1-alkyl-3-arylaminopyrrole-2,5-diones which could also be obtained from the reaction of arylaminofumarates with primary aliphatic amines. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1001–1007, July, 2007.     

A Novel and Cheap Synthesis of Artemisia Ketone1 (3,3,6-Trimethylhepta-L,5-Dien-4-One)

The Sequential dialkylation of dimethylaminoacetonitrile with first methallylchloride and then prenylbromide is performed at room temperature using K₂CO₃ in DMF. Subsequent hudrolysis and isomerisation offord artemisia ketone in 77% overall yield.