附:甲基丙烯酸(甲酯)含量等的测定方法

(一)甲基丙烯酸(甲酯)含量的测定一、原理: 由异丁酸催化脱氢生成的甲基丙烯酸,可用溴化法测其含量。溴酸钾为强的氧化剂,在酸性介质中,反应可提供已知量的溴,生成的溴可与不饱和有机物起加成反应,但此步反应较慢,应于暗处放置15分钟。     

1-氨基-2-溴-4-羟基蒽醌的生产工艺改进

据Eur.Pat.Appl.190994报道,汽巴-嘉基公司对1-氨基-2-溴-4-羟基蒽醌的生产工艺进行了改进。该工艺先将1-氨基蒽醌在浓硫酸中进行溴化,生成1-氨基-2,4-溴蒽醌,然后蒸馏除去过量的溴和反应生成的溴氢酸,然后用66％的发烟硫酸和少量三聚甲醛进行部分水解,1-氨基-2-溴-4-羟基蒽醌的收率达92％。例如,580份93％硫酸与111.5份1-氨基蒽醌在110℃     

氯吡格雷的合成研究

选择以α-溴代邻氯苯乙酸为起始原料,采用固体酸为催化剂,得到α-溴代邻氯苯乙酸甲酯;α-溴代邻氯苯乙酸甲酯与2-噻吩乙胺在溶剂中在碱作用下生成α-(2-噻吩乙胺)-2-氯苯乙酸甲酯,与甲醛经曼尼奇反应环合生成消旋氯吡格雷碱,经樟脑磺酸拆分得到氯吡格雷碱;氯吡格雷碱与硫酸反应得氯吡格雷硫酸盐,母液中主要产物R-氯吡格雷,在碱作用下消旋化,再次拆分得到氯吡格雷。     

3-溴哒嗪的合成

以3,6-二氯哒嗪为原料,与15%NaOH在100℃反应6 h,生成3-氯-6-羟基哒嗪,在碳钯的催化作用下脱氯,生成3-羟基哒嗪,与三溴氧磷在80℃反应25 min,生成3-溴哒嗪,摩尔总收率达61.2%。     

芳胺的区域选择溴化反应

用5,5-二溴丙二酸亚异丙酯作溴化试剂,室温下与 N-烷基或 N,N-二烷基芳胺在二氯甲烷中反应,可区域选择地生成对位产物。产率55～93%。     

超痕量亚硝酸根离子的气相色谱测定

<正> 在痕量亚硝酸根离子的气相色谱测定法中,将对溴苯胺与亚硝酸根离子反应生成对溴氯苯,用电子捕获检测器测定,视为高灵敏度方法,检出限达1ppb,但灵敏度尚有进一步提高的余地。我们在文献[3]的工作中,将亚硝酸根离子与苯胺进行重氮化——碘代反应,生成碘代苯,用电子捕获检测器测     

氧瓶燃烧电位滴定溴化环氧树脂中的溴

溴化环氧树脂样品用滤纸包裹,置于充满氧气的烧瓶中燃烧。样品中的碳生成二氧化碳。环氧树脂中的溴生成溴化物和少量溴酸盐或游离溴,被碱溶液吸收后经硫酸肼还原至溴化物,最后将生成的溴化物用硝酸银标准溶液进行电位滴定,采用银-特殊甘汞电极对指示终点。     

电化学辅助溴催化氧化葡萄糖制备葡萄糖酸盐

在含有溴离子和大量的碳酸钙的葡萄糖溶液中,通以直流电,使溴离子在阳极(正极)被电化学氧化成溴单质,与水结合成溴水,进一步用于氧化葡萄糖制备葡萄糖酸,葡萄糖酸与碳酸钙反应生成葡萄糖酸钙,溴变为溴离子,形成了电化学辅助溴催化氧化葡萄糖制备葡萄糖酸钙的循环系统。所制备出的葡萄糖酸钙溶液与可溶性的硫酸钠,硫酸钾,硫酸锌和硫酸亚铁通过复分解反应制备出葡萄糖酸钠,葡萄糖酸钾,葡萄糖酸锌和葡萄糖酸铁,产率大于90%。     

化学气相传输法制备无水溴化铒

报导了制备无水纯ErBr3的化学气相传输法。Er2O3为原料，无水溴化铝为溴化剂和传输介质。Er2O3与过量的溴化铝反应，生成ErBr3(s)。ErBr3(s)在高温与溴化铝反应生成气态配合物，该配合物在低温分解。利用453—753K的温度梯度场，实现ErBr3的化学气相传输，获无水纯ErBr3产物。     

4-乙酰基愈创木酚的选择性α-溴化反应研究

使用单质溴与4-乙酰基愈创木酚进行溴化反应时,产物溴化不完全,或者局部过量的溴化,且选择性较差。CuBr2在氯仿和乙酸乙酯的混合液中与酮反应可生成相应的α-溴化酮,对α-位有很好的选择性,可使用CuBr2代替单质溴与4-乙酰基愈创木酚进行有选择性的α-溴化反应。利用傅立叶红外光谱和核磁共振氢谱对其溴化产物的结构进行分析确认,并且对反应时间、反应温度和氯仿-乙酸乙酯混合液的比例对产率的影响进行了研究。     

Collisions of spheres with wet and dry porous layers on a solid wall

A theory that combines Darcy's law for flow in porous media with inelastic solid mechanics, to model collisions of solid spheres with wet or dry porous layers placed on a solid wall, is found to closely describe the trends in data collected from particle-collision experiments. An exponential-hardening, stress-strain model is used for the porous layer, validated with dynamic mechanical analyzer measurements. Low-velocity collisions were performed in the low-gravity environment afforded during parabolic flight of a KC-135 aircraft, and also under normal gravity with a pendulum-based setup. Both theory and experiments show a decrease in the dry restitution coefficient with an increase in impact velocity, mainly due to increased inelastic losses in the porous material. The wet restitution coefficient is also found to decrease with an increase in the impact velocity, in contrast to the wet restitution coefficient for collisions of a solid sphere with a wet wall without a porous layer. Moreover, a critical impact velocity (below which no rebound occurs) is observed for wet collisions without a porous layer but not with a porous layer. The wet restitution coefficient is always found to be lower than the dry restitution coefficient, due to the viscous losses associated with fluid flow in addition to the inelastic losses associated with the porous layer.     

Model filled polymers. XV: The effects of chemical interactions and matrix molecular weight on rheology

In order to explore the effects of chemical composition on the rheological behavior o filled polymeric systems, we prepared polystyrene (9PS) and poly(methyl methacrylate) (PMMA) particles crosslinked with either ethylene glycol dimethacrylate (EGDMA) or divinyl benzene (DVB), and mixed these particles in a PMMA matrix. PS particles crosslinked with 10% EGDMA are better dispersed in a PMMA matrix, compared to PS particles, crosslinked with 10% DVB, due to the compatibilizing effect of EGDMA. For PMMA particles crosslinked with DVB, particle-matrix interactions in a PMMA matrix are smaller than in EGDMA-PMMA filled PMMA. Therefore, particles tend to agglomerate in PMMA composites filled with DVB-PMMA particles, especially in a low molecular weight matrix. We compared PMMA matrices of molecular weights 35,000 and 75,000. Higher particle-matrix interaction in the higher molecular weight matrix resulted in lower relative viscosities for DVB-PS filled systems, due to better dispersion of the particles. Composites filled with EGDMA-PS particles behave similarly to those filled with DVB-PS particles. PMMA composites filled with DVB-PMMA particles have a lower relative viscosity in the higher molecular weight PMMA matrix at low shear rates, due to better dispersion in the higher molecular weight matrix. However at high shear rates, particles are well dispersed in both PMMA matrices and, then, the relative viscosity is higher due to better bonding in the higher molecular weight matrix.     

Molecular Mechanisms of Skewed X-Chromosome Inactivation in Female Hemophilia Patients—Lessons from Wide Genome Analyses

Introduction: Hemophilia A (HA) is an X-linked bleeding disorder caused by factor VIII (FVIII) deficiency or dysfunction due to F8 gene mutations. HA carriers are usually asymptomatic because their FVIII levels correspond to approximately half of the concentration found in healthy individuals. However, in rare cases, a carrier may exhibit symptoms of moderate to severe HA primarily due to skewed inactivation of her non-hemophilic X chromosome. Aim: The aim of the study was to investigate X-chromosome inactivation (XCI) patterns in HA carriers, with special emphasis on three karyotypically normal HA carriers presenting with moderate to severe HA phenotype due to skewed XCI, in an attempt to elucidate the molecular mechanism underlying skewed XCI in these symptomatic HA carriers. The study was based on the hypothesis that the presence of a pathogenic mutation on the non-hemophilic X chromosome is the cause of extreme inactivation of that X chromosome. Methods: XCI patterns were studied by PCR analysis of the CAG repeat region in the HUMARA gene. HA carriers that demonstrated skewed XCI were further studied by whole-exome sequencing (WES) followed by X chromosome-targeted bioinformatic analysis. Results: All three HA carriers presenting with the moderate to severe HA phenotype due to skewed XCI were found to carry pathogenic mutations on their non-hemophilic X chromosomes. Patient 1 was diagnosed with a frameshift mutation in the PGK1 gene that was associated with familial XCI skewing in three generations. Patient 2 was diagnosed with a missense mutation in the SYTL4 gene that was associated with familial XCI skewing in two generations. Patient 3 was diagnosed with a nonsense mutation in the NKAP gene that was associated with familial XCI skewing in two generations. Conclusion: Our results indicate that the main reason for skewed XCI in our female HA patients was negative selection against cells with a disadvantage caused by an additional deleterious mutation on the silenced X chromosome, thus complicating the phenotype of a monogenic X-linked disease. Based on our study, we are currently offering the X inactivation test to symptomatic hemophilia carriers and plan to expand this approach to symptomatic carriers of other X-linked diseases, which can be further used in pregnancy planning.     

Rheological Studies on Virgin and Metallized Unsymmetrical Dimethyl Hydrazine Gelled Systems

Rheological studies on unsymmetrical dimethyl hydrazine-methyl cellulose gelled system have been conducted under varying shear rates in order to establish its flow characteristics. The gel is found to behave as a pseudoplastic thixotrop. The viscosity build-up with respect to time has been traced till apparently a firm gel is set. The viscosity is found to increase with time rapidly in the beginning and minor changes are observed thereafter. The effect of temperature and extent of metal (Al and Mg) loading on apparent viscosity of the gelled system has also been investigated. Both the apparent viscosity and thixotropic character of the virgin gel are found to decrease with increase in temperature. An increase in rate of shear decreases the apparent viscosity significantly. The thixotropic character of the metallized gelled systems is observed to increase with metal content and that they exhibit a shearthinning behaviour too. Power law has been applied to assess the variation of pseudoplastic index n and consistency index K with temperature and metallization. The results reveal that n increases with temperature and decreases with metal loading whereas K shows an opposite trend. The yield value of gelled systems is noted to show decrease with temperature and increase with metal incorporation.     

Mechanism and kinetics of the CoCl2-catalyzed esterification reaction of castor oil with oleic acid

The apparent orders of the Lewis acid-catalyzed esterification reactions between castor oil and oleic acid are known to change with the catalyst used and with the reaction temperature. A mechanism is proposed in this study to explain the variations (with temperature) in the apparent orders of the cobalt chloride-catalyzed esterification reaction between castor oil and oleic acid. According to the proposed mechanism, an acid-catalyst intermediate forms in an initial, fast quasi-equilibrium step, and this intermediate then reacts with the oil to yield the products and to regenerate the catalyst in the rate-determining second step. A general rate expression, with an acid concentration term and a temperature-dependent constant in the denominator, is derived from the proposed mechanism and is verified with data obtained at different temperatures.     

Kinetics of tire derived fuel (TDF) char oxidation and accompanying changes in surface area

The oxidation behavior of tire-derived fuel (TDF) char has recently been studied by several groups. In the present study, TDF char oxidation has been examined between 670 and 825 K, at oxygen partial pressures ranging from 2 to 19.8 kPa. The order of reaction with respect to oxygen varied with burnoff, and was in the range 0.72-0.86. The activation energy of reaction ranged with burnoff from 138 to 150 kJ/mol. The reaction rate does not correlate well with BET surface area, but did correlate well with the surface area in pores ranging in size from 1.2 to roughly 7 nm in width. Pores smaller than 1.2 nm exist in the char, but appear not to be used or developed by the oxidation reaction. Results for chars that have been acid washed to remove some inorganic matter show lowered reactivity, and a distinctly different pattern of pore development with burnoff. This is, in turn, reflected in a very different pattern of reactivity change with burnoff for such materials.     

MicroRNA Profiling in Oesophageal Adenocarcinoma Cell Lines and Patient Serum Samples Reveals a Role for miR-451a in Radiation Resistance

Many patients with Oesophageal Adenocarcinoma (OAC) do not benefit from chemoradiotherapy treatment due to therapy resistance. To better understand the mechanisms involved in resistance and to find potential biomarkers, we investigated the association of microRNAs, which regulate gene expression, with the response to individual treatments, focusing on radiation. Intrinsic radiation resistance and chemotherapy drug resistance were assessed in eight OAC cell lines, and miRNA expression profiling was performed via TaqMan OpenArray qPCR. miRNAs discovered were either uniquely associated with resistance to radiation, cisplatin, or 5-FU, or were common to two or all three of the treatments. Target mRNA pathway analyses indicated several potential mechanisms of treatment resistance. miRNAs associated with the in vitro treatment responses were then investigated for association with pathologic response to neoadjuvant chemoradiotherapy (nCRT) in pre-treatment serums of patients with OAC. miR-451a was associated uniquely with resistance to radiation treatment in the cell lines, and with the response to nCRT in patient serums. Inhibition of miR-451a in the radiation resistant OAC cell line OE19 increased radiosensitivity (Survival Fraction 73% vs. 87%, p = 0.0003), and altered RNA expression. Pathway analysis of effected small non-coding RNAs and corresponding mRNA targets suggest potential mechanisms of radiation resistance in OAC.     

Effects of Carbon Yarn Size on the Mechanical Properties of Plain Woven C/SiC Composites

The effects of yarn size on the mechanical properties of silicon carbide composites reinforced with a plain woven carbon cloth with two sizes of yarns (1 and 3 k) were investigated. The experimental results show that the composite fabricated with 1 k yarns exhibits greater stiffness and strength than the composite fabricated with 3 k yarns. Microstructural observations revealed the existence of matrix microcracks in both the composites under the as-processed condition due to the large difference of thermal expansion between the fibers and the matrix, which are more severe for the composite with 3 k yarns. The fractured surfaces of the composite with 1 k yarns showed extensive fiber pull-out in contrast to the yarn pull-out in the composite with 3 k yarns. The larger interyarn and intrayarn voids due to difficulties of matrix infiltration in the composite with 3 k yarns represent the primary contribution to the diminished mechanical properties. Unequal yarn sizes give rise to different yarn waviness, which may be another source of difference in the mechanical properties of composites.     

高效液相色谱法测定番茄与土壤中双胍三辛烷苯基磺酸盐残留量

建立了一种用高效液相色谱测定番茄与土壤中双胍三辛烷苯基磺酸盐的定量分析方法。番茄样品用正丁醇和正己烷提取，然后加三乙胺溶液进行液液分配，经硅胶柱层析净化；土壤样品用氢氧化钠-甲醇溶液提取，然后加三氯甲烷进行液液分配，经硅胶柱层析净化。甲醇-水-氨水作流动相，荧光检测器检测，外标法定量。番茄添加水平为0．2～5．0mg／kg时，回收率为70％-88％，变异系数2．1％～8．7％；土壤添加水平为0．2～5．0mg／kg时，回收率为62％-95％，变异系数3．3％-4．9％；对番茄和土壤的最低检出浓度分别是0．05、0．10mg／kg。     

The water retention values of never-dried alkali-treated celluloses

The extent of swelling of refined and unrefined cotton linter, viscose pulp and paper pulp treated with various concentrations of NaOH from 4 to 20% at 20°C, then washed with water and never dried was measured in terms of the water retention values (WRV). The treatment of unrefined fibers with alkali resulted in increase in WRV; the only exception was viscose pulp treated with 12 and 14% NaOH. Cotton pulp refined with 5% NaOH showed an increase in the swelling ability in water which increased with the concentration of alkali treatment, whereas for viscose and paper pulps the amount of water retained increased with alkali concentration up to 12% and 14% NaOH, respectively, then decreased with further increase in alkali concentration. For cotton and viscose pulps refined with 20% NaOH, the alkali treatment increased the affinity of fibers to water up to alkali concentrations of 16% and 12% NaOH, respectively,′ then the WRV became more or less stable after treatment with higher concentrations of NaOH. On the other hand, the paper pulp refined with 20% NaOH then treated with alkali concentrations from 10 to 20% showed decreased WRV.