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氧化纤维素的制备研究 总被引:6,自引:0,他引:6
介绍了氧化纤维素 (DAC)的制备过程 ,用正交法探讨了以NaIO4 作氧化纤维素时反应温度、溶液pH值、氧化剂浓度、反应时间以及交互作用对DAC醛基含量的影响 ,找到了影响醛基含量的主要因素为反应温度、反应温度与NaIO4 的交互作用、反应温度与溶液 pH值的交互作用。初步确定了制备氧化纤维素的反应工艺 ,使醛基含量较高时的最佳反应条件为 :反应温度 3 5℃ ,反应时间 3h ,NaIO4 质量分数 6.78% ,pH值为 2时 ,醛基含量达 68.2 0 %。 相似文献
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以单宁为原料,制得酰化单宁.优化反应条件,并以酰化单宁为鞣剂进行皮革鞣制,测定皮革的性能并推断鞣制机理.结果表明,将1 g单宁溶于6 g三氟乙酸中,添加1.5 g乌洛托品,在100℃下回流反应1.5 h,制备得到醛基含量为2.33 mmol/g的酰化单宁.以酰化单宁为鞣剂,鞣制皮革的收缩温度可达(85.3±2.5)℃,撕裂强度为(47.7±1.3)N/mm,抗张强度为(10.2±1.1)MPa,断裂伸长率为97.9%±2.0%,优于未改性单宁鞣制的皮革.此外,鞣制的皮革还具有较强的抗紫外性能.酰化单宁保留了其原有的活性基团,在鞣制过程中与皮革胶原纤维分子形成氢键交联作用,引入的醛基可以和胶原纤维分子中的氨基发生反应形成稳定的化学键.在两种作用力的共同影响下,使得皮革的性能得到显著提高. 相似文献
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以紫苏醛(Ⅰ)为原料,经缩合反应制得紫苏葶(Ⅱ),然后Ⅱ与系列酰氯进行酰化反应,以70%~90%的收率得到21个紫苏醛基肟酯化合物Ⅲa~u,采用FTIR、1HNMR、13CNMR和ESI-MS对其进行了结构表征,并测试了目标化合物的除草和抑菌活性。结果表明:化合物Ⅲa~u的质量浓度为100 mg/L时,紫苏醛基甲基肟酯(Ⅲa)和紫苏醛基乙基肟酯(Ⅲb)对稗草幼苗株高生长的相对抑制率分别达到97.0%和91.0%,与阳性对照丙炔氟草胺的相对抑制率(97.5%)相当;紫苏醛基对氯苯基肟酯(Ⅲm)和紫苏醛基乙基肟酯(Ⅲb)对油菜胚根生长的相对抑制率分别为88.4%和79.6%,比丙炔氟草胺的相对抑制率(63.0%)更高。此外,在质量浓度为50 mg/L时,化合物Ⅲa~u对苹果轮纹病菌、黄瓜枯萎病菌、花生褐斑病菌、小麦赤霉病菌和番茄早疫病菌均有一定的抑菌活性,其中,Ⅲb对花生褐斑病菌和苹果轮纹病菌有较好的抑菌能力,相对抑菌率分别为85.0%和79.2%。 相似文献
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以无水溴化铝为催化剂,对氯苯甲醛为醛基化试剂,通过傅克反应在聚苯乙烯微球表面接枝醛基;基于醛基的可氧化性,利用还原剂硝酸铵铈将树脂微球表面的醛基自由基化,引发对苯乙烯磺酸钠在树脂微球表面聚合,并对其进行表征。结果表明,聚苯乙烯微球磺酸化改性成功,优化的磺化工艺条件为:醛基含量1.5 mmol/g的聚苯乙烯微球用量0.3 g,对苯乙烯磺酸钠质量浓度40 g/L,硝酸铵铈质量浓度40 g/L,反应温度70℃,在此条件下制备的树脂表面磺酸基含量为58 mmol/g。 相似文献
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以α-蒎烯(Ⅰ)为原料,经选择性烯丙位甲基氧化反应制备了桃金娘烯醛(Ⅱ),Ⅱ再经缩合反应得到了桃金娘烯醛缩氨基硫脲(Ⅲ),进一步氧化环化得到了桃金娘烯醛基噻二唑(Ⅳ),然后与系列酰氯化合物进行N-酰化反应,以66%~81%的收率合成得到了11个桃金娘烯醛基噻二唑-酰胺化合物Ⅴa~k。采用FTIR、1HNMR、13CNMR和ESI-MS对目标化合物进行了结构表征,并测试了目标化合物的抑菌和除草活性。结果表明:在化合物Ⅴa~k的质量浓度为50 mg/L时,Ⅴa~k对测试的苹果轮纹病菌、黄瓜枯萎病菌、花生褐斑病菌、小麦赤霉病菌和番茄早疫病菌均显示不同程度的抑菌活性,其中桃金娘烯醛基噻二唑-乙酰胺(Ⅴa)、桃金娘烯醛基噻二唑-氯乙酰胺(Ⅴb)和桃金娘烯醛基噻二唑-正丙酰胺(Ⅴc)对苹果轮纹病菌的相对抑制率分别为93.0%、93.0%和98.2%,化合物Ⅴb对黄瓜枯萎病菌的相对抑制率为84.3%,表现出与阳性对照嘧菌酯(对苹果轮纹病菌和黄瓜枯萎病菌的相对抑制率分别为96.0%和87.5%)相当的抑菌活性。构效分析表明:脂肪族取代基衍生物表现出更好的抑菌活性。此外,在质量浓度为100 mg/L时,化合物Ⅴc对油菜胚根生长的相对抑制率为79.6%,显示出比阳性对照丙炔氟草胺(抑制率为63.0%)更好的除草活性。 相似文献
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以苯乙烯 ( St)和甲基丙烯酸甲酯 ( MMA )为主单体 ,以丙烯醛 ( AL )为功能单体进行三元无皂乳液共聚合制备了具有反应活性的胶乳。用透射电子显微镜 ( TEM)观察了胶粒形态、大小 ,且考察了功能单体、引发剂过硫酸铵 ( APS)及交联剂二乙烯基苯 ( DVB)的浓度对胶粒形态、大小及分布的影响。同时 ,用电导滴定法测定了胶粒表面醛基的含量且探讨了功能单体的浓度及加料方法对胶粒表面醛基含量的影响。结果表明 :随AL浓度增大 ,胶粒直径 ( Dw)及其分散系数 ( Dp)增大且胶粒表面 -CHO含量增大而其百分比下降 ;随 APS及DVB浓度增大 ,Dw 减小而 Dp 增大。 AL在聚合后期加入有利于 -CHO分布在胶粒表面 ,而 AL分两批加入能进一步提高 -CHO在胶粒表面的分配量 相似文献
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The manipulation of the cationic lipid structures to increase polynucleotide binding and delivery properties, while also minimizing associated cytotoxicity, has been a principal strategy for developing next-generation transfection agents. The polar (DNA binding) and hydrophobic domains of transfection lipids have been extensively studied; however, the linking domain comprising the substructure used to tether the polar and hydrophobic domains has attracted considerably less attention as an optimization variable. Here, we examine the use of an oxime ether as the linking domain. Hydrophobic oxime ethers were readily assembled via click chemistry by oximation of hydrophobic aldehydes using an aminooxy salt. A facile ligation reaction delivered the desired compounds with hydrophobic domain asymmetry. Using the MCF-7 breast cancer, H1792 lung cancer and PAR C10 salivary epithelial cell lines, our findings show that lipoplexes derived from oxime ether lipids transfect in the presence of serum at higher levels than commonly used liposome formulations, based on both luciferase and green fluorescent protein (GFP) assays. Given the biological compatibility of oxime ethers and their ease of formation, this functional group should find significant application as a linking domain in future designs of transfection vectors. 相似文献
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以丙酮肟、盐酸为原料,经水解反应合成盐酸羟胺,研究建立了对水解可逆反应进程作定量检测的HPLC-氧化还原滴定组合分析方法,分析结果的平均回收率达99.64%,相对标准偏差≤2.04%(n=6)。建立了反应-蒸馏耦合工艺装置,研究和优化了丙酮肟水解反应制备盐酸羟胺的反应-蒸馏过程工艺条件,结果表明,当丙酮肟与盐酸的摩尔比为1∶2,盐酸质量分数为38%,加热温度为130℃,反应时间为3h时,丙酮肟原料转化率达到89%左右,盐酸羟胺产品收率达到84%左右。 相似文献
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Masahiro Sugiura Kazuhiro Fukumoto 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1993,57(1):57-63
The removal of gaseous aldehydes by amino acids and by their sodium salts and hydrochlorides was studied in ambient air with the relative humidity of 30% at 25°C. Amino acid sodium salts, diamino acids, sodium p-aminobenzoate (PABANa), and o-aminobenzoate (OABANa), and p-aminobenzoic acid (PABA) on sepiolite, both having a carboxylato functionality (? COO?) together with an amino (? NH2) group, were highly reactive with aldehydes. In contrast, PABA which has free carboxylic acid functionality (? COOH: dimeric) was not so reactive with aldehydes. Normal amino acids and their hydrochlorides having ammonio (? NH2+) and ? COO? or ? COOH (dimeric) groups were less reactive with aldehydes. The reactivity was closely related to the degree of dissociation of carboxylate anion; as the degree of dissociation increases, the compound becomes more reactive. p-Aminobenzoic acid hydrochloride (PABA · HCl), having ? NH3+ and ? COOH (monomeric) groups, was the most reactive (with ethanal) of all the amino acids and their salts examined. Amino acid sodium salts, diamino acid, PABANa, OABANa, and PABA on sepiolite are proved to be excellent removers of aldehydes in ambient air. Among them, PABA · HCl is particularly good for ethanal. 相似文献
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针对钛硅分子筛(TS-1)催化环己酮氨肟化反应在浆态条件下进行时存在的固液分离和溶剂回收等问题,尝试采用微乳化的方法加以解决。以十六烷基三甲基溴化铵(CTAB)/水/氨水/环己酮的水包油(O/W)型微乳液作为反应介质,实现了TS-1催化环己酮的氨肟化反应。通过实验考察了反应温度及助表面活性剂(叔丁醇)的用量对反应选择性及转化率的影响。结果表明,升高反应温度,在环己酮转化率随之提高的同时,环己酮肟的选择性先升高后降低,且在65℃时达到最高;而助表面活性剂(叔丁醇)的用量对环己酮的转化率没有明显影响,却显著影响了反应的选择性。X射线衍射图和傅立叶变换红外谱图显示,所得的环己酮肟结晶度好、纯度高。 相似文献
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Acetals that react with cotton to form cellulose crosslinks are derived from dialdehydes that can form five-or-six-membered tetrahydrofuran or tetrahydropyran rings. These aldehydes themselves are reactive to cotton, but the acetals do not form the aldehyde to react. The acetals were less reactive than the aldehydes and formed crosslinks with a different structure. Intrinsic reactivity of acetals increased with increased branching in the alkoxy group. but the increase was often hidden by the effect from changing solvents. In some instances a greater reactivity with methyl acetals was pronounced. Strength loss in cotton fabric from crosslinking was greater with acetals than with conventional crosslinking agents because even the most reactive acetals were less reactive and required more rigorous reaction conditions than conventional agents. 相似文献
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《分离科学与技术》2012,47(1-3):201-225
Abstract U.S. Bureau of Mines researchers investigated the use of aliphatic oximes to extract nickel from acidic, nickelous-chromic-chloride solutions. Batch solvent extraction tests were conducted to characterize the nickel extraction and stripping properties of several oximes. Results indicated that the oximes selectively extracted nickel over chromium by an ion pair mechanism. Nickel was most effectively stripped from the loaded oxime extractants with dilute hydrochloric acid; however, these acidic strip solutions partially degraded the oximes to their parent aldehydes by hydrolysis. The oximes could, however, be regenerated by contacting the solvent phase with a neutralized hydroxylamine-hydrochloride solution. Decyl oxime was successfully used in a continuous counter-current solvent extraction circuit that incorporated loading, stripping, and regeneration stages. The decyl oxime degraded 12 pct per loading and stripping cycle, but was effectively regenerated prior to recycling to the head of the circuit. 相似文献
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The content of the sternal gland secretion from four male koalas (Phascolarctos cinereus) was analyzed using gas chromatography–mass spectrometry. Volatile fatty acids, aldehydes, ketones, mono- and sesquiterpenes were identified, together with various volatile nitriles and oximes, some of which had not previously been described from any mammalian skin gland. Benzyl cyanide and phenylacetaldehyde oxime were identified as major components of the secretions, together with smaller amounts of the novel 3-methylthiopropanal oxime. The relative abundance of the identified compounds was highly variable between individuals and the scent composition was found to be partly determined by the scent of surrounding conspecifics. Principal component analysis revealed a high similarity between related individuals. 相似文献
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在前期工作基础上继续由酮肟1与氢化钠作用产生酮肟阴离子2,酮肟阴离子再与α-乙氧羰基乙烯基膦酸二乙酯3作用产生膦酸酯取代的碳负离子4,该碳负离子进一步与醛作用得到α-乙氧羰基烯丙基肟醚化合物,产率在81%~85%。 相似文献
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《Journal of Catalysis》2006,237(2):359-367
The liquid-phase ammoximation of cyclohexanone with ammonia and hydrogen peroxide was conducted over Ti-MWW. Ti-MWW is capable of giving both cyclohexanone conversion and oxime selectivity >99% under optimum reaction conditions. It is a highly active, selective, and reusable catalyst for the synthesis of cyclohexanone oxime in the presence of water. In comparison to other titanosilicates, Ti-MWW shows much higher catalytic activity, even superior to that of TS-1. The catalytic performance of Ti-MWW depends greatly on the operating conditions of the reaction, especially the method of adding substrates. The reason why the method of adding substrates plays such an important role in the ammoximation of ketones or aldehydes over Ti-MWW was investigated after a detailed evaluation of the reaction mechanism. 相似文献