以硅胶为载体通过γ -胺丙基三甲氧基硅烷偶联剂制备季铵盐类水不溶性杀菌的方法研究（Ⅱ）

在利用硅胶表面上的羟基通过( -胺丙基硅烷把季铵盐固载到硅胶载体上制成水不溶性杀菌剂的基础上,考察了原料硅胶对制备产品杀菌性能的影响.在相同操作条件下,使用同一种原料硅胶,随着原料粒度的减小,所制备杀菌剂产品的杀菌率有所增加,但不明显;选用不同种原料硅胶合成的水不溶性季铵盐类杀菌剂的杀菌结果表明,原料比表面积越大,孔体积越小,合成产品的杀菌率越高.红外光谱证明了γ -胺丙基三甲氧基硅烷已通过与硅胶表面羟基的反应键合到硅胶表面,叔胺化的硅胶中间体和产物上存在的很强的烷基峰也证明了硅胶上确实固载上了烷基官能团.交叉极化的硅核磁共振谱有效地表征了硅胶上表面羟基的反应情况,δ为-106处峰的基本消失证明了原料硅胶表面的硅羟基与胺丙基硅烷的键合反应比较完全.使用后的杀菌剂再生结果表明,其再生性能良好,具备重复使用的特点.     

以硅胶为载体通过γ-胺丙基三甲氧基硅烷偶联剂制备季铵盐类水不溶性杀菌剂的方法研究(II)

在利用硅胶表面上的羟基通过g -胺丙基硅烷把季铵盐固载到硅胶载体上制成水不溶性杀菌剂的基础上,考察了原料硅胶对制备产品杀菌性能的影响。在相同操作条件下,使用同一种原料硅胶,随着原料粒度的减小,所制备杀菌剂产品的杀菌率有所增加,但不明显;选用不同种原料硅胶合成的水不溶性季铵盐类杀菌剂的杀菌结果表明,原料比表面积越大,孔体积越小,合成产品的杀菌率越高。红外光谱证明了 -胺丙基三甲氧基硅烷已通过与硅胶表面羟基的反应键合到硅胶表面,叔胺化的硅胶中间体和产物上存在的很强的烷基峰也证明了硅胶上确实固载上了烷基官能团。交叉极化的硅核磁共振谱有效地表征了硅胶上表面羟基的反应情况,为-106处峰的基本消失证明了原料硅胶表面的硅羟基与胺丙基硅烷的键合反应比较完全。使用后的杀菌剂再生结果表明,其再生性能良好,具备重复使用的特点。     

以硅胶为载体通过γ—胺丙基三甲氧基硅烷偶联剂制备季铵盐类水溶性杀菌剂的方法研究（Ⅱ）

在利用硅胶表面上的羟基通过γ－胺丙基硅烷把季铵盐固载到硅胶载体上制成水不溶性杀菌剂的基础上，考察了原料硅胶对制备产品杀菌性能的影响。在相同操作条件下，使用同一种原料硅胶，随着原料粒度的减小，所制备杀菌剂产品的杀菌率有所增加，但不明显；选用用不同种原料硅胶合成的水不溶性季铵盐类杀菌剂的杀菌结果表明，原料比面积越大，孔体积越小，合成产品的杀菌率越高。红外光谱证明了γ－胺丙基三甲氧基硅烷己通过与硅胶表面羟基的反应键合到硅胶表面，叔胺化的硅胶中间体和产物上存在的很强的烷基峰也证明了硅胶上确实固载上了烷基官能团。交叉极化的硅胶核共振谱有效地表征了硅胶上表面羟基的反应情况，δ为－106处峰的基本消失证明了原料硅胶表面的硅羟基与胺丙基硅烷的键合反应比较完全。使用后的杀菌剂再生结果表明，其再生性能好，具备重复使用的特点。     

交联结构对水不溶性聚季铵盐类杀菌性能的影响

水不溶杀菌剂;氯球;交联结构对水不溶性聚季铵盐类杀菌性能的影响     

以硅胶为载体通过3—胺丙基三甲氧基硅烷偶联剂制备季铵盐类水溶性杀菌剂的方法研究（Ⅰ）

采用硅胶作为制备水溶性季铵盐杀菌剂的原料,以γ-胺丙基三甲氧基硅作为联接硅胶和杀菌活性官能团的偶联剂,在硅胶上键合γ－胺基三甲氧基硅烷的最佳反应条件为：使用二甲苯作反应溶剂,80℃反应6h以上,硅烷与硅胶的重量比为1：1左右,固载硅烷的硅胶叔胺化条件为：使用甲苯和二甲苯作反应溶剂,100℃反应4h以上,甲酸与甲醛的体积比为1：1,使用所研制的中间体制备的水下溶性杀剂量用在2mg/ml时杀菌率达到97％。     

硅胶负载型硫酸锆表面相结构的理论研究

采用量子化学ASED-MO(含原子对排斥的EHMO法)为基础的结构自动优化EHTOPT法研究了硅胶负载型硫酸锆表面相的结构特征。在对硅胶表面结构单元和四水硫酸锆单体空间模型结构参数进行优化的基础上,依据四水硫酸锆与硅胶载体表面的成键状态、电荷布居及能量变化,从理论上分析了四水硫酸锆与载体表面之间静电和脱水的相互作用的合理模型及硅胶负载型硫酸锆的结构稳定性,阐明了硫酸锆在载体表面的分散趋向于单分散的特征。     

聚烯烃催化剂载体硅胶研发进展

以Ziegler-Natta催化剂和茂金属催化剂为例,介绍了聚烯烃均相催化剂的负载化技术以及载体选择的影响因素,明确了载体的强度、密度、总孔容、孔分布、孔径、粒度和颗粒形状等物理性质是选择载体要考虑的主要因素。综述了聚烯烃催化剂载体硅胶的结构特征和性能特征,并对聚烯烃催化剂载体硅胶的合成机理、影响因素进行了详细介绍。此类载体硅胶比表面积280~320m2/g、堆密度0.28~0.32g/cm3、孔容1.40~1.70cm3/g、平均孔径18~22nm。建议通过开展对不同性能硅胶(如更小粒径、不同元素改性等)的研究开发,以满足不同催化剂对载体硅胶的特殊要求。     

高效液相色谱法所用大孔硅胶填料的制备

对国产ＧＹＱＧ球形硅胶施加高压水热处理并进行扩孔，制备了用于高效液相色谱法的大孔硅胶填料，考察了扩孔压力，扩孔温度和扩孔时间对平均孔径和比表面积的影响。并将产品日本ＳＩＬ－３００３×１０＾－８ｍ硅胶进行了物理性质和孔分布的对比实验，结果表明ＧＹＱＧ硅胶扩孔后平均孔径为２０～３０ｎｍ接近日本ＳＩＬ－３００３×１０＾－８ｍ硅前平平均孔径２５ｎｍ。display structure     

甲壳胺-硅胶复合载体的制备及其在脂肪酶固定化中的应用

固定化脂肪酶;甲壳胺-硅胶复合载体的制备及其在脂肪酶固定化中的应用     

硅胶担载的高锰酸钾对烯烃碳碳双键的氧化

在无有机溶剂做介质的条件下，用硅胶吸附的高锰酸钾氧化6种难溶于水的液态烯烃，得到了双键发生断裂的氧化产物。该反应操作简便，反应快，收率好。此外，对硅胶的活化作用机制进行了浅要。     

分离蛋白质的高效离子交换色谱填料的研究(Ⅳ)──强阴离子交换色谱填料的合成及应用

含环氧基的硅胶与二乙胺或聚乙烯亚胺反应,其产物再与碘甲烷或氯化苄反应,得到含季铵离子的强阴离子交换色谱填料。该填料可用于蛋白质和生物工程产品(如基因重组人干扰素γ、粒细胞-巨噬细胞集落刺激因子和人绒毛膜促性腺素等)的分离纯化。其中,环氧基硅胶与二乙胺加成后再用氯化苄季铵化的产物是较好的强阴离子交换色谱填料。     

Bacterial adhesion inhibition of the quaternary ammonium functionalized silica nanoparticles

Quaternary ammonium compounds have been considered as excellent antibacterial agents due to their effective biocidal activity, long term durability and environmentally friendly performance. In this work, 3-(trimethoxysilyl)-propyldimethyloctadecylammonium chloride as a quaternary ammonium silane was applied for the surface modification of silica nanoparticles. The quaternary ammonium silane provided silica surface with hydrophobicity and antibacterial properties. In addition, the glass surface which was coated with the surface modified silica nanoparticles presented bacterial growth inhibition activity. For comparison of bacterial growth resistance, hydrophobic silane (alkyl functionalized silane) modified silica nanoparticles and pristine silica nanoparticles were prepared. As a result of bacterial adhesion test, the quaternary ammonium functionalized silica nanoparticles exhibited the enhanced inhibition performance against growth of Gram-negative Escherichia coli (96.6%), Gram-positive Staphylococcus aureus (98.5%) and Deinococcus geothermalis (99.6%) compared to pristine silica nanoparticles. These bacteria resistances also were stronger than that of hydrophobically modified silica nanoparticles. It could be explained that the improved bacteria inhibition performance originated from the synergistic effect of hydrophobicity and antibacterial property of quaternary ammonium silane. Additionally, the antimicrobial efficacy of the fabricated nanoparticles increased with decreasing size of the nanoparticles.     

Adsorption of cholic acid on surface of organosilicas containing chemically bound quaternary ammonium groups

It was found that silica modified with quaternary ammonium groups exhibits higher adsorption properties than cholesteramine, a sequestering adsorbent used in medicine for regulating the level of cholic acids in the organism. The constants of ion-exchange, aggregation, and stability, as well as the distribution coefficients, for synthesized organosilicas were calculated. It was shown that adsorption of cholic acid depends on the structure of the quaternary ammonium groups grafted to the silica surface.     

High-performance liquid chromatography on dynamically modified silica : III. Modification of silica with long-chain and symmetrical quarternary ammonium compounds

The influence of the nature of quaternary ammonium compounds on retention in high-performance liquid chromatography on dynamically modified silica was investigated. Adsorption isotherms were determined on bare silica (LiChrosorb Si 60) for four alkyltrimethylammonium bromides and two symmetrical tetraalkylammonium bromides, each containing 15–21 carbon atoms. It was found that only the long-chain quaternary ammonium ions are adsorbed on to the silica surface in appreciable amounts and that the affinity increasing number of carbon atoms in the alkyl chain. The maximum amount that can be adsorbed per gram of silica is of the same order of magnitude for each of the four long-chain quaternary ammonium compounds. This amount, however, is reached at lower concentrations in the eluent the longer is the alkyl chain.The retention of five test compounds was determined over the whole concentration range investigated for each of the modiflying agents. The surfactant concentration that causes maximum retention for four of five test compounds coincides with its critical micellar concentration. The retention mechanisms and the influence of the type of the modifying agent on selectivity are discussed, and compared with published results on related experiments on chemically bonded stationary phases.     

Rapid determination of bromide in seawater samples by capillary ion chromatography using monolithic silica columns modified with cetyltrimethylammonium ion

Monolithic silica capillary columns dynamically modified with quaternary ammonium ions were evaluated for the determination of bromide in seawater samples. A quaternary ammonium ion such as cetyltrimethylammonium ion was dynamically introduced onto monolithic silica surfaces. The first layer of the modifier was introduced by electrostatic interaction, whereas the second layer was introduced by hydrophobic interaction. The latter layer worked as the anion-exchange sites. The modified monolithic silica capillary columns could be used for rapid separation of inorganic anions. Separation of authentic mixture of five anions was achieved within a few minutes. The addition of small amount of the modifier in the eluent improved the repeatability of the retention time. Seawater samples could be directly injected onto the prepared capillary columns, and bromide could be determined to be 63 mg/L.     

Synthesis and Reaction of a Silica-Supported Catalyst with Ammonium Groups. Immobilized Ammonium Groups on Silica

The immobilization of lipophilic quaternary ammonium salts onto the large areas of the surface of silica has been accomplished. The modified silica served as a catalyst for the nucleophilic replacement of benzylic halides by cyanide.     

Analysis of Quaternary Ammonium Compounds by Ion-Pair Thin Layer Chromatography on Silica Gel

Abstract

A general approach to the chromatographic analysis of quaternary ammonium compounds on silica gel thin layers is described. The quaternary cations migrate as ion pairs with bromide or iodide as counter ions. Methanol or chloroform-methanol mixtures serve as developing solvents, in which excess amounts of NaBr or NaI are dissolved. If the solvent cannot dissolve sufficient quantities of halide salts, the latter can be sprayed onto the plate as a methanol solution prior to development. The separation patterns of the quaternary ammonium compounds can be influenced by the choice of counter ion and by the choice of the organic solvent components.     

Estimation of the dissociation constants for functional groups on modified and unmodified silica gel supports from the relationship between electroosmotic flow velocity and pH

Electroosmotic volume flow was directly observed in a simple instrument consisting of 1 cm long a home-made support, packed between two polyethylene frits in the polypropylene tube. Equations relating electroosmotic flow (EOF) velocity and pH for two functional groups on the surface of the solid materials were developed. With these equations, we can estimate the dissociation constants of two different kinds of functional groups on modified silica gel materials simultaneously. The dissociation constants of silanol groups, benzene sulfonic acid groups, and alkyl quaternary ammonium groups on the modified and unmodified silica gel supports were estimated. The estimated pK values of the silanol groups on the silica gel and modified silica gel surfaces are between 4.0 and 4.3. The estimated pK values of the benzene sulfonic acid groups and alkyl quaternary ammonium groups on the surface of the modified silica gel are 2.6 and 8.6, respectively.     

Non-modified stationary phases for the analysis of basic compounds

The analysis of some basic solutes, particularly quaternary ammonium compounds, utilizing reversed-phase liquid chromatography on chemically modified silica, is still difficult. One alternative is the application of unmodified stationary phases, such as alumina and silica, in combination with aqueous solvent mixtures for the separation of these analytes.     

Synthesis of main-chain chiral quaternary ammonium polymers for asymmetric catalysis using quaternization polymerization

Main-chain chiral quaternary ammonium polymers were successfully synthesized by the quaternization polymerization of cinchonidine dimer with dihalides. The polymerization occurred smoothly under optimized conditions to give novel type of main-chain chiral quaternary ammonium polymers. The catalytic activity of the polymeric chiral organocatalysts was investigated on the asymmetric benzylation of N-(diphenylmethylidene)glycine tert-butyl ester.