共查询到18条相似文献,搜索用时 156 毫秒
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为了研究多巴在D(L)-2酒石酸异丁酯1,2二氯乙烷有机相和羟丙基-β-环糊精水相萃取体系中的分配行为;运用双相(O/W)识别手性萃取,考察酒石酸构型和浓度、羟丙基-β-环糊精浓度、水相pH值等因素对萃取性能的影响。羟丙基-β-环糊精对S-多巴对映体的识别能力大于对R-多巴对映体的识别能力,而L-酒石酸异丁酯的识别能力刚好相反;在羟丙基-β-环糊精和L-酒石酸异丁酯萃取体系中,多巴外消旋体一次萃取分离后R和S对映体的分配系数(kR和kS)分别为8.92和5.34,分离因子α达1.67;同时pH值和萃取剂浓度对手性分离能力有显著的影响。双相(O/W)识别手性萃取具有较强的手性分离能力,它对外消旋体化合物的制备性分离有着十分重要的意义。 相似文献
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氟比洛芬是临床上常用的非甾体抗炎类手性药物,主要用于治疗类风湿性关节炎和骨关节炎。其S型对映体有较高的药理活性而R型对映体药效较低且有一定毒副作用,因此获得单一的光学纯S-氟比洛芬对映体具有重要应用价值。在之前工作基础上,研究利用含手性离子液体为水相萃取剂和酒石酸酯为油相萃取剂的双相识别手性萃取系统对氟比洛芬消旋体进行了手性拆分。研究了酒石酸酯种类,有机溶剂种类,油相手性选择剂浓度,氟比洛芬消旋体浓度,pH及温度对萃取过程的影响,并通过反萃取过程实现了手性离子液体的循环回用。结果表明,在1-丁基-3-甲基咪唑L-色氨酸([Bmim][L-trp])浓度0.02 mol·L~(-1),D-酒石酸二辛酯浓度0.3 mol·L~(-1),氟比洛芬浓度50μg·mL~(-1),二氯乙烷为有机溶剂,pH=2.0,25℃下,体系选择性达到1.31。相比于单相手性识别,双相手性识别体系选择性得到较大改善。 相似文献
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研究了布洛芬对映体在含有疏水性L-酒石酸酯的1,2-二氯乙烷溶液及甲醇水溶液两相中的萃取分配行为,考察了不同烷基链长的L-酒石酸酯、D-酒石酸酯以及L-酒石酸酯的浓度、有机溶剂的种类和溶解布洛芬的甲醇水溶液浓度对分配系数K和分离因子α的影响。实验表明,L-酒石酸酯与布洛芬Ⅱ对映体形成的复合物稳定性比与布洛芬Ⅰ对映体形成的复合物稳定性要大,而D-酒石酸酯的萃取性能则与此相反,它与布洛芬Ⅰ对映体形成的复合物稳定性比与布洛芬Ⅱ对映体形成的复合物稳定性要大。有机溶剂的萃取性能为醇>1,2-二氯乙烷>烷烃,随着溶解布洛芬的甲醇水溶液中甲醇浓度的增大,分配系数K和分离因子α均降低,当甲醇的浓度为10%时,可以得到最佳的K和α。随着L-酒石酸酯浓度的提高,分配系数K和分离因子α先增大后减小,当L-酒石酸酯的浓度约为0.2 mol·L-1时,K和α达到最大值;L-酒石酸酯的碳链长度对分配系数K和分离因子α也有很大的影响。 相似文献
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在自制键合型纤维素-(4-甲基苯甲酸酯)手性固定相上,分别在正相、反相及极性有机相色谱模式等多种模式下对农药禾草灵进行了手性拆分,考察了流动相中极性改性剂(醇、四氢呋喃、三氯甲烷、二氯甲烷、乙腈)对禾草灵手性拆分的影响.实验结果表明:键合型纤维素-(4-甲基苯甲酸酯)手性固定相对禾草灵具有良好的手性选择性,可在多种模式下使用,样品均可获得手性分离.其最佳手性分离在V(正己烷)∶V(异丙醇)∶V(四氢呋喃)=90∶5∶5时获得,分离度(Rs)达2.39. 相似文献
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研究了酮洛芬对映体在含疏水性手性选择体L-酒石酸正丁酯的1,2-二氯乙烷和甲醇水两相体系中的萃取分配行为.考察了酒石酸酯的种类、L-酒石酸正丁酯的浓度、有机溶剂的种类及甲醇溶液的浓度对分配系数K和分离因子α的影响.L-酒石酸正丁酯与S-酮洛芬对映体比L-酒石酸正丁酯与R-酮洛芬对映体形成更稳定的非对映体复合物;以0.2mol/L L-酒石酸正丁酯为手性选择体,以1,2-二氯乙烷为有机溶剂,甲醇浓度为10%时,萃取分离效果最好. 相似文献
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以3-氯-苯丙酮为原料,螺硼酸酯为催化剂,采用不对称催化还原法合成手性中间体(R)-3-氯-苯丙醇。考察了溶剂对催化剂活性的影响以及催化剂用量、硼烷用量和温度对产品纯度和光学纯度的影响。以乙酸乙酯溶剂中制得的手性螺硼酸酯为催化剂,在n(3-氯-苯丙酮):n(螺硼酸酯):n(硼烷)=1:0.1:0.6,反应温度5~10℃条件下,产品纯度达99.5%,产品光学纯度96.3% e.e.。 相似文献
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Wenjing Wu Michael P. Cronin Lynne Wallace Anthony I. Day 《Israel journal of chemistry》2018,58(3-4):479-486
The chiral amines (R,R and S,S)-1-amino-2-benzyloxycyclopentane and (R and S)-α-methylbenzylamine were converted to ammonium (D and L) hydrogen tartrate salts and induced chiroptic effects were investigated following encapsulation in Q[7]. Significant chiroptic differences were observed in ORD and CD spectra for the two amines. The optical spectra were performed as a precursor study to a potential method for enantiomer separation, utilising Q[7] encapsulation in conjunction with enantio-pure hydrogen tartrates. An enantiomeric excess was achieved for the two antipodes of 1-amino-2-benzyoxycyclopentane but not for those of α-methylbenzylamine. However, material differences of crystallinity or the formation of a glass were observed for the latter amine induced by the different antipodes of hydrogen tartrate. 1H NMR spectra of aminobenzyloxycyclopentane showed back-folding of the two rings with complete encapsulation in Q[7], leading to a secondary helical structure observed in CD spectra. 相似文献
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硼酸的生产应用现状及市场前景 总被引:1,自引:0,他引:1
介绍了当前硼酸的生产概况和应用现状,并结合实际提出了今后的发展前景。各国硼矿资源各有特点,其生产硼酸的方法也不尽相同,但以酸法为主。硼酸在玻璃工业、陶瓷、机械、电子、医药、农业、国防及现代科学技术领域有着广泛应用。未来世界硼工业将向集约化、规模化、精细化方向发展。高附加值的硼精细化工产品、新型含硼材料,专用(医药、试剂、照相、反应堆)级别的高纯或无水硼酸将有更为广阔的发展。 相似文献
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Galvanoluminescence of high purity aluminium was found to have two fundamental origins: one was the luminescence associated with scintillation or with some concommitant side reactions, taking place at the flaws; the other was the luminescence associated with anions included in the films during anodization. The former appeared to be the origin of the luminescence in inorganic electrolytes such as ammonium borate, borax, borax plus boric acid etc; and the latter appeared to be responsible for the luminescense in organic acids and their salts, such as oxalic, citric, tartaric and succinic acids and ammonium tartrate. 相似文献
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研究了乳酸、酒石酸钾钠、硼酸和柠檬酸钠等对铝合金化学镀Ni-P沉积速率的影响,并对镀层的结合强度以及耐蚀性等方面进行了考察,确定了合适的工艺条件。根据该工艺制备的Ni-P镀层具有良好的表面质量和较高的结合强度,提高了基体的耐蚀性。 相似文献
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The distribution behavior of mandelic acid (MA) enantiomers was examined in a two‐phase system containing di(2‐ethylhexyl) phosphoric acid (D2EHPA) with two tartaric acid derivatives as complex chiral selectors in n‐octanol. Factors affecting the extraction were investigated, including the structure and concentration of tartaric acid as well as the concentration of D2EHPA and D,L‐MA. The results showed that both the distribution ratio and enantioselectivity were greatly improved by using a complex chiral selector rather than using the tartaric acid derivative by itself. Finally, it was found that the formation of mixed complex chiral selectors by mixing two tartaric acid derivatives with D2EHPA can improve the capacity of enantioselective extraction. 相似文献
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The kinetics of forward extraction of boric acid from salt lake brine by 2-ethyl-1,3-hexanediol in tolu-ene was investigated using the single drop technique. The factors affecting the extraction rate include interfacial area between aqueous phase and organic phase, initial concentration of boric acid in aqueous phase, initial concen-tration of 2-ethyl-1,3-hexanediol in organic phase, and extraction temperature. The experimental results show that the extraction rate increases with the increase of the initial concentration of boric acid and 2-ethyl-1,3-hexanediol, interfacial area of two phases, and temperature. With the temperature-dependence study, it is showed that the ex-traction is a diffusion-controlled process. The kinetic equation is presented for pH 1.0 in the aqueous phase and temperature of 318 K. 相似文献