木素分子氧化性氨化反应过程中的结构变化

在一定压力和温度条件下，木素大分子和氨发生反应，生成一些氮修饰木素。为了解反应过程中木素分子结构的变化，用^1^3C和^1H-^1^3C2D-NMRHMQC技术检测了反应前后的分子谱图，结果显示反应过程中木素分子的碎裂化现象十分明显，很可能在氧化性氨化反应过程中，木素大分子表面基团发生了氧化性修饰，如一些侧链CH~3被氧化形成CHO和COOH等，然后这些基团与氨结合等；此外，芳香环结构可能通过粘康酸单体断裂形成一些酰胺类产物，但木素分子内部的高度缩合性结构没有明显的变化。     

松柏醇-β-D-葡萄糖苷-[α—^13 C]与造纸废水中LCC的聚合反应

为了有效地去除废水中水溶性、难降解木素及木素碳水化合物复合体(LCC),降低废水的污染负荷.文研究了在木素氧化酶催化下,木素前驱物松柏醇-β-D-葡萄糖苷-[α-13C]与废水中的木素碳水化合物复合体反应的方法及其机理.采用了13C同位素示踪技术,并结合红外谱图分析、核磁共振技术来探讨聚合产物的化学结构.同时应用了GPC分析手段测定了聚合产物的相对分子质量Mn.研究表明:木素前驱物松柏醇-β-D-葡萄糖苷能与废水中LCC发生脱氢聚合反应,同时GPC测定的结果表明聚合后相对分子质量也明显增大,Mn从406上升为23810-36886.反应生成聚合产物为疏水性较好的木素-碳水化合物复合大分子而沉淀析出.     

电化学氧化油页岩反应机理的研究

本文进一步考察了电化学氧化黄县油页岩过程。利用DSC、IR等分析技术研究了反应前后油页岩有机质性质的变化情况。初步认为电解氧化优先发生在油页岩有机质的芳环结构单元上,导致油页岩有机质三维网络结构的破裂,形成大量羧酸。反应过程中的氧化剂主要为阳极产生的活性氧基团而不是分子氧。     

硅胶表面接枝手性树枝状大分子的合成与表征

以氨丙基硅胶为核,通过与丙烯酸甲酯和乙二胺进行多次重复的Michael加成反应以及酰胺化反应制得在硅胶表面接枝的树枝状大分子(G);G进一步通过L-苯丙氨酸(L-Phe)的手性修饰得到在硅胶表面接枝的手性树枝状大分子(G-L-Phe).G和G-L-Phe的结构经~(13)C NMR,IR及SEM表征.     

氨基修饰β-环糊精衍生物水相仿生催化不对称Michael加成反应

在不对称 Michael加成反应中,有机小分子如伯胺、吡咯烷类衍生物、(硫)脲类、手性方酰胺、联萘类、奎宁类、手性膦、离子液体和肽类等是目前使用的主要催化剂,如果能避免或少量使用有机溶剂,则更符合“绿色化学”的环境友好发展方向.β-环糊精的内腔疏水,而外部亲水,可以类似酶分子结合有机反应物,在水相体系进行催化反应.当β-环糊精分子上连接催化部位或结合部位时,能产生更优异的包结底物和诱导对映选择性的能力.目前基于β-环糊精衍生物构筑人工类酶催化剂用于不对称 Michael加成反应的报道较少.本文通过亲核取代反应将氨基类有机小分子与单(6-O-p-甲苯磺酰基)-β-环糊精结合,得到9个氨基修饰β-环糊精衍生物CD-1–CD-9(收率在24.2%–64.9%,分子结构通过1H NMR,13C NMR和 ESI-MS表征确认),并用于室温水相体系不对称Michael加成的仿生催化反应,以期获得较好的催化反应活性和对映选择性.通过设计不同β-环糊精衍生物的修饰基团结构、改变反应介质pH值和反应底物结构,分析了Michael加成反应体系产物产率和对映选择性的变化,采用2D-1H ROESY NMR、紫外吸收光谱、红外光谱和和量子化学计算,分析了β-环糊精衍生物和反应底物分子的包结状态,探究了反应过程机理.结果显示,在该水相体系中进行的不对称Michael加成反应产物产率和对映体过量值(ee值)受修饰基团结构、反应介质pH值和底物结构影响较大.当反应介质pH值低于6.0时,由于氨基分子被质子化而失去催化活性;当 pH值为7.5时,获得中等水平的对映选择性,通过量子化学在 ONIOM (B3LYP/6-31G(d)：PM3)水平上的优化计算发现,底物分子与β-环糊精衍生物的包结可以出现两种形式：当底物分子的活性部位接近β-环糊精衍生物小口端的修饰基团时,产生分子内催化,诱导反应产生较好的对映选择性;当底物分子的活性部位远离β-环糊精衍生物小口端的修饰基团时,产生分子间催化,几乎没有对映选择性,而这两种情况同时存在.当底物分子以较大的空间位阻与β-环糊精疏水性空腔结合时,产生较好的对映选择性,邻位取代的2-硝基-β-硝基苯乙烯比对位取代的4-硝基-β-硝基苯乙烯 ee值更高,通过量子化学优化计算证实空间位阻效应.应用2-金刚烷酮与β-环糊精衍生物空腔形成竞争性的包结反应实验,产物产率和ee值都下降,说明β-环糊精衍生物的疏水性空腔是产生不对称诱导和催化活性不可或缺的部分,底物分子与β-环糊精衍生物的包结过程通过2D-1H ROESY NMR和紫外吸收图谱获得确认.其中L-2-氨甲基吡咯烷修饰β-环糊精 CD-1表现出较好的反应对映选择性,在溶剂(pH =7.5,0.5 mol/L CH3COONa-HCl)2 mL,环己酮2 mmol,2-硝基-β-硝基苯乙烯0.2 mmol,CD-1用量0.04 mmol,25°C反应96.0 h的条件下,环己酮与2-硝基-β-硝基苯乙烯 Michael加成产物的 ee值达71%,产率为47%.该反应过程在β-环糊精衍生物的疏水性空腔内进行,修饰基团L-2-氨甲基吡咯烷与环己酮形成烯胺的催化反应.     

通过熔体自由基反应调控聚丙烯体系的链结构和相结构

熔融反应加工是聚合物改性和制备聚合物纳米复合材料的重要途径之一.在此过程中,多数加成聚合物由于受到热、剪切或引发剂作用,通常可原位形成大分子自由基反应中间体.我们系统地研究了如何利用这类大分子自由基调控聚合物分子链的拓扑结构和聚合物纳米复合体系的相结构与界面.然而,某些聚合物大分子自由基,如聚丙烯(PP),受其分子链化学结构决定,在熔融反应条件下非常易于发生降解.研究发现,将可控自由基聚合中调控自由基反应活性的方法应用在熔融反应过程中可以显著抑制PP的降解,促进主反应的发生,在制备长链支化聚合物、调控聚合物纳米复合材料的相结构方面发挥了重要作用.本文介绍了本研究组近几年来通过熔体自由基反应调控PP体系的链结构和相结构的相关研究工作,如实现PP的长链支化,制备高熔体强度PP;在制备PP/C60 、PP/碳纳米管(CNTs)纳米复合材料过程中,利用熔体界面区域所发生的自由基反应,提高了纳米粒子与PP的界面相互作用,改善了纳米粒子在PP中的分散状态等.     

具有 MWW 结构钛硅分子筛的研究进展

 综述了具有 MWW 结构钛硅分子筛的制备方法、孔道和晶体结构的调变和修饰以及催化应用三个方面的研究进展. 与 TS-1 相比, 具有 MWW 结构钛硅分子筛的制备方法多种多样; 其孔道结构可塑性强, 通过采用层间剥离、柱撑以及分子水平硅烷化插硅扩孔技术, 可以增大和暴露孔道和外表面, 满足不同选择氧化反应的要求. 由于 MWW 结构钛硅分子筛拥有复杂而独特的孔道结构, 所以在小分子 (如直链烯烃等) 的环氧化反应, 和大分子 (环状烯烃, 二苯并噻吩等) 氧化反应中都表现出优异的催化性能. 此外, 该钛硅分子筛表现出与 TS-1 完全不同的溶剂效应, 用于烯丙基氯液相环氧化与酮类氨氧化反应主产物选择性更高.     

铑(Ⅲ)催化吲哚甲酰胺衍生物与末端炔烃的C—H活化/环化反应

报道了铑(Ⅲ)催化的吲哚甲酰胺衍生物与末端的炔烃发生的C—H活化/环化反应,能够高效地构建多环吲哚类化合物,收率为85%~98%.该反应操作简便、反应条件温和、催化剂用量低,并使用具有氧化性的导向基团,不需要添加额外氧化剂.研究了该反应的分子间的竞争性试验,推测了可能的反应机理.所有化合物均采用NMR,IR,高分辨质谱等多种谱学技术进行了结构表征.     

过渡金属-双硫分子配合物的理论研究

采用密度泛函方法, 对一系列过渡金属-双硫分子配合物的结构和相关性质进行了理论计算研究, 讨论了中心金属原子、配体等结构修饰对分子性质的影响. 计算结果表明, 过渡金属双硫分子配合物的HOMO和LUMO轨道主要由其配体轨道组成, 且其能隙很小; 中心金属原子和配体中一些基团的改变对分子配合物构型的影响很小, 而且HOMO-LUMO能隙变化不大. 配合物的氧化主要表现在配体部分, 氧化过程对调控HOMO-LUMO能隙具有十分重要的作用.     

氨基修饰β-环糊精衍生物水相仿生催化不对称Michael加成反应（英文）

在不对称Michael加成反应中,有机小分子如伯胺、吡咯烷类衍生物、(硫)脲类、手性方酰胺、联萘类、奎宁类、手性膦、离子液体和肽类等是目前使用的主要催化剂,如果能避免或少量使用有机溶剂,则更符合"绿色化学"的环境友好发展方向.β-环糊精的内腔疏水,而外部亲水,可以类似酶分子结合有机反应物,在水相体系进行催化反应.当β-环糊精分子上连接催化部位或结合部位时,能产生更优异的包结底物和诱导对映选择性的能力.目前基于β-环糊精衍生物构筑人工类酶催化剂用于不对称Michael加成反应的报道较少.本文通过亲核取代反应将氨基类有机小分子与单(6-O-p-甲苯磺酰基)-β-环糊精结合,得到9个氨基修饰β-环糊精衍生物CD-1–CD-9(收率在24.2%–64.9%,分子结构通过~1H NMR,~(13)CNMR和ESI-MS表征确认),并用于室温水相体系不对称Michael加成的仿生催化反应,以期获得较好的催化反应活性和对映选择性.通过设计不同β-环糊精衍生物的修饰基团结构、改变反应介质pH值和反应底物结构,分析了Michael加成反应体系产物产率和对映选择性的变化,采用2D-~1HROESY NMR、紫外吸收光谱、红外光谱和和量子化学计算,分析了β-环糊精衍生物和反应底物分子的包结状态,探究了反应过程机理.结果显示,在该水相体系中进行的不对称Michael加成反应产物产率和对映体过量值(ee值)受修饰基团结构、反应介质pH值和底物结构影响较大.当反应介质pH值低于6.0时,由于氨基分子被质子化而失去催化活性;当pH值为7.5时,获得中等水平的对映选择性,通过量子化学在ONIOM(B3LYP/6-31G(d):PM3)水平上的优化计算发现,底物分子与β-环糊精衍生物的包结可以出现两种形式:当底物分子的活性部位接近β-环糊精衍生物小口端的修饰基团时,产生分子内催化,诱导反应产生较好的对映选择性;当底物分子的活性部位远离β-环糊精衍生物小口端的修饰基团时,产生分子间催化,几乎没有对映选择性,而这两种情况同时存在.当底物分子以较大的空间位阻与β-环糊精疏水性空腔结合时,产生较好的对映选择性,邻位取代的2-硝基-β-硝基苯乙烯比对位取代的4-硝基-β-硝基苯乙烯ee值更高,通过量子化学优化计算证实空间位阻效应.应用2-金刚烷酮与β-环糊精衍生物空腔形成竞争性的包结反应实验,产物产率和ee值都下降,说明β-环糊精衍生物的疏水性空腔是产生不对称诱导和催化活性不可或缺的部分,底物分子与β-环糊精衍生物的包结过程通过2D-~1HROESYNMR和紫外吸收图谱获得确认.其中L-2-氨甲基吡咯烷修饰β-环糊精CD-1表现出较好的反应对映选择性,在溶剂(pH=7.5,0.5mol/LCH_3COONa-HCl)2mL,环己酮2mmol,2-硝基-β-硝基苯乙烯0.2mmol,CD-1用量0.04mmol,25°C反应96.0h的条件下,环己酮与2-硝基-β-硝基苯乙烯Michael加成产物的ee值达71%,产率为47%.该反应过程在β-环糊精衍生物的疏水性空腔内进行,修饰基团L-2-氨甲基吡咯烷与环己酮形成烯胺的催化反应.     

Ion-exchange properties of ammoniated lignin

The oxidative ammonolysis of hydrolysis lignin from sunflower husks has given ion-exchange materials with amphoteric properties. The greatest total exchange capacity of the sample with respect to 0.1 N caustic soda solution amounted to 11.5 meq/g, and with respect to 0.1 N hydrochloric acid solution to 0.6 meq/g. The processes of ion exchange with heavy-metal cations are accompanied by complex formation. The bond of the metal cations with the lignin in the complexes is effected through nitrogen and the oxygen of a nonalcoholic group.     

Ammonolysis of technical lignins

The oxidative ammonolysis of hydrolysis lignin, cellolignin, and lignosulfonate takes place effectively with the greatest formation of a water-soluble fraction at 140–150°C in 2 h. On oxyammonolysis, cellolignin forms approximately twice as much water-soluble fraction as hydrolysis lignin, while lignosulfate desulfonates under conditions exceeding the optimum. The maximum amount of nitrogen in the water-soluble fraction of lignin (nitrogen-containing lignin) amounts to 9.0% for cellolignin and is 2–3% less for the others.M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 275–278, March–April, 1987.     

Ion-exchange properties of ammoniated lignin

The oxidative ammonolysis of hydrolysis lignin from sunflower husks has given ion-exchange materials with amphoteric properties. The greatest total exchange capacity of the sample with respect to 0.1 N caustic soda solution amounted to 11.5 meq/g, and with respect to 0.1 N hydrochloric acid solution to 0.6 meq/g. The processes of ion exchange with heavy-metal cations are accompanied by complex formation. The bond of the metal cations with the lignin in the complexes is effected through nitrogen and the oxygen of a nonalcoholic group.Astrakhan Technical Institute of the Fish Industry and Agriculture. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 636–640, September–October, 1981.     

Oxidative ammolysis of wood under the conditions of cavitation treatment

Effect of the composition of the lignocarbohydrate vegetable raw material, treatment duration, amount of ammonium persulfate, and concentration of free ammonia on the yield of the target product and on its content of nitrogen, carboxy groups, and lignin upon oxidative ammonolysis of vegetable waste with ammonium persulfate in aqueous ammonia under the conditions of cavitation treatment was examined. The agrochemical tests of the products as nitrogen-containing fertilizers were performed.     

木质素催化转化制取苯、甲苯和二甲苯

对HZSM-5、HY和MCM-22三种催化剂进行了比较,其中HZSM-5催化裂解木质素制备苯、甲苯和二甲苯（BTX）的结果最优．确定了木质素催化裂解的最佳反应条件,包括反应温度、载气流速、催化剂／木质素配比．当反应温度为550-600℃,载气流速为300mL／min,催化剂／木质素配比为2时,使用HZSM-5催化裂解制备BTX的最高C产率和芳香选择性分别可达25．3％和90．9％。     

P(MeNCH2CH2)3N: an efficient catalyst for the desilylation of tert-butyldimethylsilyl ethers

tert-Butyldimethylsilyl (TBDMS) ethers of primary, secondary, and tertiary alcohols and phenolic TBDMS ethers are desilylated to their corresponding alcohols and phenols, respectively, in DMSO, at 80 degrees C, in 68-94% yield in the presence of 0.2-0.4 equiv of P(MeNCH2CH2)3N. Using P(i-PrNCH2-CH2)3N as the catalyst, 85-97% yields of desilylated alcohols were obtained from TBDMS ethers of 1-octanol, 2-phenoxyethanol, and racemic alpha-phenyl ethanol. These are the first examples of desilylations of silyl ethers catalyzed by nonionic bases. Both catalysts were much less effective for the desilylation of tert-butyldiphenylsilyl (TBDPS) ethers (22-45% yield) under the same conditions as used for TBDMS ethers. Possible pathways involving nucleophilic attack of the anion of the solvent molecule (generated by the catalyst) at the Si-O bond of silyl ether or a prior activation of the silyl ether by the catalyst via a P-Si interaction followed by nucleophilic attack of the solvent anion are proposed on the basis of 1H and 31P NMR experimental data.     

Enthalpy of hydrophobic hydration separately estimated for each -CH2-, -CF2-, and -OCH2CH2- unit component of amphiphiles and of related compounds

The enthalpy of hydrophobic hydration, DeltaH(HH), was separately estimated for each apolar segment of amphiphiles and of related compounds. The specimens analyzed in this study were the homologs and analogs of sodium alkyl sulfate, alkyltrimethylammonium bromide, ammonium perfluoroalkylcarboxylate, and polyethylene glycols. The DeltaH(HH) was calculated from the adiabatic compressibility beta of aqueous solution systematically measured for each homologs at varying concentrations and temperatures. Those data reported in the previous paper were utilized. The DeltaH(HH) estimated for each -CH(2)-, -CF(2)-, and -OCH(2)CH(2)- segments in both hydrophobic and hydrophilic parts of the amphiphiles was found to change depending on its locations in the molecule. The DeltaH(HH) for the first -CH(2)- unit which is adjacent to the head sulfate group of H(CH(2))(n)SO(4)Na was found to be negligibly small; however, it increases gradually as the position of the unit moves apart from the anionic head group and attains as large as -26.5 kcal/mol for the eighth -CH(2)-. The change of DeltaH(HH) of -CF(2)- unit in F(CF(2))(n)COONH(4) shows the similar tendency to H(CH(2))(n)SO(4)Na. The value of DeltaH(HH) is as small as -8 kcal/mol for the first -CF(2)-, however, it increases to -16 kcal/mol for the fifth -CF(2)-, which is 1.5 times larger than that of the fifth -CH(2)- of alkyl sulfate. Contrary to this, all the DeltaH(HH) of the methylenes of cationic surfactant ranging from the second to the eighth -CH(2)- units of H(CH(2))(n)N(CH(3))(3)Br take a similar value around -8 kcal/mol of -CH(2)- irrespective of their positions. The first -CH(2)- unit which is equivalent to that of quaternary ammonium [HCH(2)](4)NBr shows slightly higher value of -9.0 kcal/mol of the first -CH(2)- than those for the second to eighth -CH(2)-. This seems to suggest that the cationic core nitrogen has an enhancing effect on hydrophobic hydration. The hydration enthalpy DeltaH(OEH) of each oxyethylene (OE) unit of polyethylene glycol was also estimated for H(OCH(2)CH(2))(p)OH (p=1-4) homologues to see the roles of ether oxygen and hydroxyl groups in hydrophobic hydration. The value of DeltaH(OEH) showed its maximum -13.1 kcal/mol for the OE unit located at the middle of three. The other two units at both ends were found to take the value of -9.9 kcal/mol, smaller than that at the center. This could suggest that the hydrophobic hydration of the ethylene segment is largely enhanced by the neighboring ether oxygens.     

Mass spectral studies of a series of N,N-dialkyl aminoethyl-2-chlorides and trimethyl silyl ethers of N,N-dialkyl aminoethane-2-ols under electron impact conditions

The electron impact (EI) mass spectra of a series of N,N-dialkyl-aminoethyl-2-chlorides, N(R(1))(R(2))-CH(2)-CH(2)Cl and trimethylsilyl ethers of N,N-dialkyl aminoethane-2-ols, N(R(1))(R(2))-CH(2)-CH(2)-O-Si(CH(3))(3), where R(1) and R(2) = methyl, ethyl, propyl and isopropyl, which are precursors of VX type of compounds, are studied. All the compounds (1-20) show abundant molecular ions, in addition to a weak [M - H](+) ion, except the N,N-diisopropyl group containing compounds (8 and 18). A general EI fragmentation pattern for the above two series of compounds is discussed. The observed fragment ions are due to simple homolytic cleavages, and they are distinct to allow the identification of the compounds unequivocally including those of isomeric compounds. The primary fragmentation of compounds 1-20 is beta-cleavage, i.e. homolytic cleavage of C-C bond, which is linked to the nitrogen atom. Three types of beta-cleavages are possible for these compounds, in which the abundance of beta-cleavage product ions is found to depend on the size and structure of the alkyl group attached to nitrogen. The alpha-cleavage fragment ions are found only for N,N-dialkyl aminoethyl-2-chlorides but are absent in the corresponding trimethylsilyl ethers of N,N-dialkyl aminoethane-2-ols. The retention indices are calculated for all the studied compounds (1-20) and are in the ranges of 750.38-1079.24 for 1-10 and 905.23-1190.25 for 11-20.     

Oxidative Ammonolysis of 2,4,6-Collidine at Vanadium-Titanium Oxide Catalyst

4-Cyanopyridine was synthesized from the readily obtainable 2,4,6-collidine by oxidative ammonolysis in the presence of vanadium-titanium oxide catalyst. Conditions under which the yield of the product amounted to 73% on the amount of the trimethylpyridine were found.