N,N-二甲基-N-丙烯基十六烷基溴化胺在水溶液中胶束化行为的研究

用表面张力法、电导率法和稳态荧光光谱法测得可聚合阳离子型表面活性剂N,N-二甲基-N-丙烯基十六烷基溴化胺(AA16DB)在25℃下的临界胶束浓度分别为0.64,1.17,0.5 mol/L,对应的表面张力为34.00 mN/m,表明AA16DB具有较高的表面活性.通过吉布斯吸附等温式计算出了AA16DB在液-气界面的过饱和吸附量和单分子截面积.与普通阳离子表面活性剂相比,AA16DB在液-气界面的过饱和吸附量较小,单分子截面积较大.

N,N-二甲基-N-丙烯基十六烷基溴化胺的合成及表征

红外光谱、核磁共振氢谱和质谱证实,以溴代丙烯与N,N-二甲基十六烷基胺为主要原料所合成的产品为阳离子表面活性剂单体N,N-二甲基-N-丙烯基十六烷基溴化胺,并且其纯度很高.

阳离子表面活性剂N，N-二甲基-N-丙烯基十二烷基溴化胺在水溶液中囊泡向胶束的转变

研究阳离子表面活性剂N，N-二-甲基-N-丙烯基十二烷基溴化胺（ADDB）分子在水溶液中的自聚集行为．用动态激光光散射（DLS）和透射电镜（TEM）观察分子聚集体的大小和形貌变化．当ADDB浓度为10mM／L、温度25℃下时．分子聚集体以囊泡和少量短棒状胶束形式存在；当浓度增大到50mM／L时，分子聚集体主要以囊泡形式存在；当浓度高达100mM／L时．囊泡全部转化为长棒状胶束．结果表明：表面活性剂ADDB在水溶液中的浓度对表面活性剂分子自聚集体的形貌影响很大，这一结果为通过控制溶液的浓度实现调控分子聚集体的结构提供了可靠的依据．

Modeling and Kinetic Study on Absorption of CO2 by Aqueous Solutions of N-methyldiethanolamine in a Modified Wetted Wall Column

To get more accurate kinetic data of the absorption of CO2 into aqueous solution of N-methyldiethanolamine,a wetted wall column was modified to more uniformly distribute the liquid on the column surface and gas in the absorbing chamber and change the length of the column.The average liquid film thickness and the liquid-phase mass transfer coefficient were measured,and a correlation for the Sherwood number,Reynolds number and Schmidt number was obtained for the modified wetted wall column.The equilibrium concentrations in chemical reactions were calculated with a minor absolute error for calculating the rate constant more accurately.A mathe-matical model for the CO2 absorption was established based on the diffusional mass transfer accompanied with parallel reversible reactions,and the partial differential equation was solved by Laplace transform.An analytical ex-pression for the concentration of carbon dioxide as a function of time and penetration depth in liquid film and the average interphase mass transfer rate was obtained.This model was also used to calculate the rate constant for a second-order reaction,which was in good agreement with reported data.

红花石蒜苯丙氨酸解氨酶催化合成N-甲基-L-苯丙氨酸

【背景】N-甲基-L-苯丙氨酸是一种N-烷基化芳香氨基酸,是重要的手性合成单元/中间体/组成成分,在医药、农业、食品等领域有重要应用价值的代谢产物中广泛存在。N-烷基化芳香氨基酸的合成与制备仍具有巨大的挑战。【目的】在研究加兰他敏的生物合成过程中,我们从产加兰他敏的红花石蒜中克隆并表征苯丙氨酸解氨酶LrPAL3。LrPAL3催化区域及对映选择性的氢胺化反应得到L-苯丙氨酸。通过生物信息学分析,推测LrPAL3可能催化反式-肉桂酸的一步N-甲基胺化反应得到N-甲基-L-苯丙氨酸。【方法】将反式-肉桂酸与甲胺,以及表达LrPAL3的大肠杆菌全细胞一起孵育。HPLC-DAD及HRESIMS分析表明,上述反应产物为N-甲基-苯丙氨酸。为确定该产物的立体构型,将上述催化反应放大,通过分离纯化得到该酶催化反应产物。【结果】该化合物的氢谱数据及比旋光数据与N-甲基-L-苯丙氨酸标准品的数据一致。由此说明,LrPAL3能够催化反式-肉桂酸和甲胺发生N-烷基胺化反应,区域和立体专一性地生成N-甲基-L-苯丙氨酸。【结论】本研究为手性N-烷基氨基酸的不对称合成提供了一种全新的绿色、高效生物催化剂。通过对LrPAL3的蛋白质定向进化及代谢工程,将会进一步扩展LrPAL3的催化反应范围,以多种N-烷基胺类及取代的苯基丙烯酸为底物,实现手性N-烷基-芳基氨基酸的高效区域及立体选择性生物合成。

Industrial Synthesis of N-Methylhydroxylamine Hydrochloride by Electrochemical Reduction of Nitromethane

An industrial electrolytic cell was designed for the electrochemical synthesis of N-methylhydroxylamine hydrochloride （N-MHA）. Copper was used as the cathode, graphite as the anode, and a cation membrane as the separator. The results show that N-MHA with a high purity of 99% can be electrosynthesized directly from nitromethane in HC1 solution. Under a constant current of 1000-2500A.m^-2 in the temperature of 30-50℃, the average yield, current efficiency, and reaction selectivity were 65%, 70%, and 99%, respectively. Graphite electrode and membrane material can be used continuously in the preparative electrolysis for 5000h. Moreover, the effects of the electrode and membrane materials, current intensity, electrolyte temperature, and other associated parameters on the electrosynthesis results were investigated. The direct current power consumption was 8151.3kW-h-（1000kg N-MHA）^ -1. This method is a simple separation process with limited contamination and hence, is a new green synthesis method for the industrial production of N-MHA.

Severity of ulcerative colitis is associated with a polymorphism at diamine oxidase gene but not at histamine N-methyltransferase gene

AIM： To analyse the role of two common polymorphisms in genes coding for histamine metabolising enzymes as it relates to the risk to develop ulcerative colitis （UC） and the clinical course of these patients. METHODS： A cohort of 229 unrelated patients with UC recruited from a single centre and 261 healthy volunteers were analysed for the presence of Thr105Ile and His645Asp amino acid substitutions at histamine N-methyltransferase （HNMT） and diamine oxidase （ABP1） enzymes, respectively, by amplification-restriction procedures. All patients were phenotyped and followed up for at least 2 years （mean time 11 years）. RESULTS： There were no significant differences in the distribution of ABP1 alleles between ulcerative colitis patients and healthy individuals [OR （95% CI） for variant alleles = 1.22 （0.91-1.61）]. However, mutated ABP1 alleles were present with higher frequency among the 58 patients that required immunosuppresive drugs [OR （95 % CI） for carriers of mutated alleles 2.41 （1.21-4.83; P=0.006）], with a significant gene-dose effect （P= 0.0038）. In agreement with the predominant role of ABP1 versus HNMT on local histamine metabolism in human bowel, the frequencies for carriers of HNMT genotypes or mutated alleles were similar among patients,regardless clinical evolution, and control individuals. CONCLUSION： The His645Asp polymorphism of the histamine metabolising enzyme ABP1 is related to severity of ulcerative colitis.

Mixed hetero-/homogeneous TiO_(2)/N-hydroxyimide photocatalysis in visible-light-induced controllable benzylic oxidation by molecular oxygen

Homogeneous and heterogeneous types of catalysis are frequently considered as separate disciplines or even opposed to each other.In the present work,a new type of mixed het-ero-/homogeneous catalysis was demonstrated for the case of selective alkylarene oxidation by molecular oxygen.The proposed catalytic system consists of two widely available components:N-hydroxyphthalimide(NHPI,a homogeneous organocatalyst for free-radical chain reactions)and nanosized TiO_(2)(heterogeneous UV-active photoredox catalyst).The interaction of NHPI with TiO_(2) allows for a shift from UV to visible light photoredox activity and generation of phthalimide-N-oxyl(PINO)radicals that diffuse into the solution where NHPI/PINO-catalyzed free-radical chain reaction can proceed without the additional light input providing a fundamental increase in energy efficiency.The NHPI/TiO_(2) ratio controls the selectivity of oxidation affording preferential formation of hydroperoxide or ketone from alkylarene.

Selective aerobic oxidation promoted by highly efficient multi-nitroxy organocatalysts

Selective oxidation with molecular oxygen as the sole oxidant under mild conditions is of crucialimportance for the long‐term sustainable exploitation of available feedstocks and the formation ofrequired intermediates for organic synthesis and industrial processes.Among the developed oxidationprotocols,innovative strategies using hydroxyimide organocatalysts in combination with metallicor metal‐free cocatalysts have attracted much attention because of the good activities andselectivities of such catalysts in the oxo functionalization of hydrocarbons.This method is based onthe reaction using N‐hydroxyphthalimide,which was first reported by Ishii’s group in the1990s.Although the important and wide‐ranging applications of such catalysts have been summarizedrecently,there are no reviews that focus solely on oxidation strategies using multi‐nitroxy organocatalysts,which have interesting properties and high reactivities.This review covers the concisesynthetic methods and mechanistic profiles of known multi‐nitroxy organocatalysts and summarizessignificant advances in their use in efficient aerobic oxidation.Based on a combination of experimentaland theoretical results,guidelines for the future rational design of multi‐nitroxy organocatalystsare proposed,and the properties of various model multi‐nitroxy organocatalysts are predicted.The present overview of the advantages,limitations,and potential applications of multi‐nitroxyorganocatalysts can provide useful tools for researchers in the field of selective oxidation.

Ru(Ⅱ)-catalyzed ortho-amidation and decarboxylation of aromatic acids: a versatile route to meta-substituted N-aryl benzamides

Carboxylate as a promising and valuable directing group has attracted a great deal of attention.However,employing it as a traceless direction group has rarely been reported.We developed the ruthenium-catalyzed amidation of substituted benzoic acids with isocyanates via directed C–H functionalization followed by decarboxylation to afford the corresponding metasubstituted N-aryl benzamides,in which the carboxylate serves as a unique,removable directing group.Notably,this protocol can provide an efficient alternative to access meta-substituted N-aryl benzamides,which are much more difficult to prepare than ortho-substituted analogues.

Synthesis and electrochemical properties of a series of novel tetra(4-benzoyl)phenoxyphthalocyanine derivatives

A novel phthalocyanine, 2,9（10）,16（17）,23（24）-tetra（4-benzoyl）phenoxyphthalocyanine, and its complexes with Zn（Ⅱ）, Cu（Ⅱ）, Co（Ⅱ）, and Ni（Ⅱ） have been synthesized and characterized by a combination of elemental analysis, IR, IH NMR, UV-vis spectroscopy and mass spectrometry. All of the materials are very soluble in common organic solvents such as dichloro- methane, chloroform, tetrahydrofuran, N,N-dimethylformamide and dimethyl sulfoxide. The Q band wavelengths of the com- plexes decrease in the order： Zn 〉 Cu 〉 Ni 〉 Co. Redox processes were observed at -1.06, -0.74, 0.51 and 0.98 V for the free phthalocyanine, at -0.72 and 1.04 V for the Co（Ⅱ） complex, at -1.24, -0.77, -0.24, 0.61 and 0,91 V for the Cu（Ⅱ） complex, and at -0.74 and 1.20 V for the Ni（Ⅱ） complex. The cyclic voltammograms of the phthalocyanine ring of the four species are similar, with reduction and oxidation couples each involving a one-electron transfer process.

Transparent conductive reduced graphene oxide thin films produced by spray coating

Reduced graphene oxide thin films were fabricated on quartz by spray coating method using a stable dispersion of reduced graphene oxide in N,N-Dimethylformamide.The dispersion was produced by chemical reduction of graphene oxide,and the film thickness was controlled with the amount of spray volume.AFM measurements revealed that the thin films have near-atomically flat surface.The chemical and structural parameters of the samples were analyzed by Raman and XPS studies.It was found that the thin films show electrical conductivity with good optical transparency in the visible to near infrared region.The sheet resistance of the films can be significantly reduced by annealing in vacuum and reach 58 k?with a light transmittance of 68.69%at 550 nm.The conductive transparent properties of the reduced graphene oxide thin films would be useful to develop flexible electronics.