两种方法制备竹炭基固体磺酸催化缩酮反应的研究

用两种方法制备竹炭基固体磺酸,研究两种竹炭基固体磺酸对催化缩酮反应的影响;考察催化剂的不同制备方法对催化效能的影响,同时考察催化剂用量、酮醇比、不同底物对转化率的影响。实验结果表明:合成缩酮的最佳反应条件是采用30%磷酸浸泡48 h处理的催化剂,固体磺酸用量相对于酮2%mol(酸量),酮醇摩尔比为1∶2,酮平均转化率可达90%以上;竹炭基固体磺酸对缩酮类化合物的合成具有良好的催化效果和稳定的催化性能。     

双活性磺酸基蔗渣木聚糖对羟基苯甲酸酯的合成及活性模拟

以蔗渣木聚糖(BX)为主要原料、氨基三磺酸钠为酯化剂,在一步酯化合成磺酸基蔗渣木聚糖酯的基础上,利用磺酸基蔗渣木聚糖酯和对羟基苯甲酸进行二步酯化反应,合成了磺酸基蔗渣木聚糖对羟基苯甲酸酯,并考察了反应条件对酯化反应的影响,通过单因素实验确定了第二步酯化反应较佳的合成工艺条件.蔗渣木聚糖酯化改性前后的样品分别用FT-IR,DG-DTG和XRD进行了表征,并对该双酯化衍生物的分子进行了优化与活性模拟.结果表明:FT-IR证明双酯化产物含有磺酸基团和对羟基苯甲酸酯基团,TG-DTG分析表明该双酯化衍生物的热稳定性提高,XRD说明发生双酯化改性后分子排列的规整性提高,结晶度增加;活性模拟实现了磺酸基蔗渣木聚糖对羟基苯甲酸酯与艾滋病毒的对接.     

生物质炭基磺酸催化合成14-苯基-14H-二苯并[a,j]氧杂蒽的研究

以松树皮为原料,通过炭化和磺化得到炭基磺酸;以该新型固体磺酸催化合成14-苯基-14H-二苯并[a,j]氧杂蒽化合物,考察了催化剂制备过程中的炭化方式、反应温度、反应时间、催化剂用量等因素对反应的影响。结果表明,萘酚/苯甲醛=4 mmol∶2 mmol、8%mol炭基磺酸催化剂(相对于醛)、反应时间为1 h、反应温度为100℃,无溶剂条件下收到最好的效果。     

磺酸基甜菜碱共聚物的合成及其界面活性研究

以N-[3-(二甲氨基)丙基]丙烯酰胺与1,3-丙磺酸内酯为原料,制备了3-[(3-丙烯酰胺)丙基-二甲氨基]丙磺酸钠甜菜碱型单体,并将其与丙烯基聚乙二醇通过自由基聚合物反应合成了磺酸基甜菜碱和聚乙二醇的共聚物。利用红外光谱(FT-IR)和凝胶渗透色谱仪(GPC)对共聚物进行表征,并考察了在高浓度CaCl2条件下该共聚物作为转向剂的界面性质变化。结果表明,在高盐的水溶液中,该共聚物仍然具有很好的稠化能力,是一种潜在的抗Ca^2+稠化剂。     

（2-羟基-3-丁氧基）丙基-羟丙基壳聚糖/聚乙二醇互穿网络凝胶的制备及其释药作用

将壳聚糖改性为（2-羟基-3-丁氧基）丙基 羟丙基壳聚糖（2-H-3-B-P-HPCS）,并以（2-羟基-3-丁氧基）丙基-羟丙基壳聚糖和聚乙二醇（PEG）为原料制备（2-羟基-3-丁氧基）丙基-羟丙基壳聚糖/聚乙二醇互穿网络凝胶,研究了（2-羟基-3-丁氧基）丙基-羟丙基壳聚糖浓度、聚乙二醇的用量、交联剂戊二醛用量、反应温度对该凝胶溶胀性能的影响。 通过红外光谱分析和扫描电子显微镜的方法比较了壳聚糖、（2-羟基-3-丁氧基）丙基-羟丙基壳聚糖和（2-羟基-3-丁氧基）丙基-羟丙基壳聚糖/聚乙二醇互穿网络凝胶结构和形态上的不同。 以阿昔洛韦为模型药物研究了其释药性能。 结果表明,该凝胶均具有良好的溶胀性、pH敏感性和药物缓释作用,有望用作新型的药物载体。     

磺酸功能化的MCM-41催化三乙酸甘油酯与甲醇的酯交换反应

通过在孔壁上覆盖糠醇聚合物,于不同温度下用浓硫酸直接进行磺化制备了一系列磺酸基功能化的MCM-41介孔材料,并用氮气吸附-脱附、XRD、XPS和红外光谱等方法对其进行了结构表征,以三乙酸甘油酯和甲醇的酯交换反应为模型反应研究了生物柴油的制备.结果表明,在介孔结构完好的情况下,一定数量的磺酸基嫁接到了MCM-41的孔擘上...     

N-(2-磺酸基苯甲基)壳聚糖的合成、表征及其水凝胶的pH敏感性

通过两步反应合成了水溶性的N-(2-磺酸基苯甲基)壳聚糖(SBCS), 用IR, 1H NMR和UV-Vis谱对产物的结构进行了表征. 用胶体滴定法测定了N上2-磺酸基苯甲基的取代度. 以戊二醛为交联剂制备了N-(2-磺酸基苯甲基)壳聚糖水凝胶(SBCSG), 考察了凝胶在不同pH值缓冲溶液中的溶胀行为. 实验结果表明, SBCSG溶胀度随着凝胶交联度的增大而减小. 在碱性介质中SBCSG的溶胀度显著增大, 而在酸性介质中溶胀度显著减小, 在pH= 5.0缓冲液中的溶胀度达到最小值. SBCSG在碱性介质中的溶胀度随着侧链N上2-磺酸基苯甲基取代度增大而增大. 在pH=7.4的人工肠液和pH=1.0的人工胃液中SBCSG的溶胀-收缩具有可逆性, 显示出良好的pH敏感性. 有望作为pH敏感口服结肠定位给药系统药物载体.     

通过芳磺酸酯不同化学键的可选择性断裂构建不同的芳基醚

实现了利用芳磺酸酯作原料通过各种化学键的选择性断裂制备芳基烷基醚和二芳基醚, 实现了利用吸电子基取代的芳磺酰氯与酚的反应来制备二芳基醚. 在K₂CO₃作用下, 分别利用酯基部分苯环上是吸电子基取代的芳磺酸芳基酯通过S―O键断裂与醇的反应, 芳磺酸烷基酯通过C―O键断裂与酚的反应来合成芳基烷基醚. 在K₃PO₄作用下, 利用吸电子基取代的芳磺酸芳基酯、芳磺酰氯通过C―S键断裂与酚的反应来制备邻位具有吸电子位阻官能团的二芳基醚; 此外, 在缺少相应酚的情况下, 上述的芳磺酸芳基酯在同样的条件下也可以得到相同的二芳基醚.     

双重响应性生物基自修复凝胶的制备及其性能

为拓宽多重响应性凝胶在生物医学领域中的应用,本文基于生物大分子构筑具有pH响应、糖响应性的可自修复性水凝胶。 本文选用3-氨基苯硼酸(APBA)和2,3-环氧丙基三甲基氯化铵(CHGTA)分别对聚谷氨酸(γ-PGA)和瓜尔胶(GG)进行改性制备了聚谷氨酸-g-氨基苯硼酸(γ-PGA-g-APBA)和阳离子瓜尔胶,在此基础上,对γ-PGA-g-APBA和阳离子瓜尔胶进行物理共混制备生物基凝胶。 通过傅里叶变换红外光谱仪(FTIR)、核磁共振波谱仪(¹H NMR)和流变仪对聚合物化学结构、接枝率、流变性能和力学性能进行表征,并考察了凝胶在不同pH值及糖浓度下刺激响应性。 结果表明,凝胶具有自修复性,修复效率可达100%;具有pH响应性,在环境pH值较高时更易形成凝胶,且凝胶强度随pH值升高而增大;同时所制凝胶具有糖响应性,在4 g/L的葡萄糖溶液中浸泡后即可导致凝胶解体。 这些结果说明功能基团APBA的引入可赋予凝胶多重响应性。 所制的双重响应性生物基凝胶具有良好的生物相容性,有望应用于生物医学、功能器件、传感等领域。     

磺酸功能化双核离子液体催化合成双酚F

合成并表征了4种具有Brnsted酸性的磺酸功能化咪唑类离子液体催化剂,考察了其在催化苯酚、甲醛合成双酚F反应中的催化活性.结果表明磺酸功能化双核离子液体双-(3-磺酸丙基-1-咪唑)亚丁基硫酸氢盐([DPSIM][HSO4]2)不仅催化活性最佳,还提高了4,4’-双酚F异构体的含量.以[DPSIM][HSO4]2为催化剂,在苯酚与甲醛摩尔比30∶1、离子液体催化剂质量浓度6.8%、反应温度90℃、反应时间60 min的优化条件下,双酚F收率可达94.1%,同时提出了其催化合成双酚F的反应机理.该离子液体催化剂腐蚀性低,易分离回收,在重复使用6次后,双酚F收率仍在70%以上.     

Preparation,Characterization and Anticoagulant Activity of Guar Gum Sulphate

Guar gum was chemically modified by sulphonation using chlorosulphonic acid (ClSO₃H) as a reagent. Effects of molar ratio of ClSO₃H to glucopyranosic unit (ClSO₃H/GU), reaction time and reaction temperature on the degree of sulphonation (DS) and molecular weight (Mw) of products were studied. The structures of guar gum sulphate were investigated by GPC, FT‐IR and UV‐Visible spectroscopy. Activated partial thromboplastin time (APTT) assay showed that the guar gum sulphate could inhibit the intrinsic coagulant pathway. The anticoagulant activity strongly depended on the DS and Mw of polysaccharides. DS>0.56 was essential for anticoagulant activity. The guar gum sulphate with the DS of 0.85 and the Mw of 3.40×10⁴ had the best blood anticoagulant activity.     

羟丙基瓜尔胶在离子液体中的制备

本文以离子液体1-烯丙基-3-甲基咪唑氯盐(AmimCl)为反应介质,以氢氧化钠为催化剂合成了羟丙基瓜尔胶(HPG),并通过1H NMR确定了产品的摩尔取代度。探讨了水的用量、环氧丙烷的用量、反应温度和反应时间对摩尔取代度的影响。在水与瓜尔胶的质量比为1.7、氢氧化钠与瓜尔胶的质量比为5%、环氧丙烷与瓜尔胶的质量比为3.5、反应温度为60℃和反应时间为12h的条件下,摩尔取代度(MS)可以达到0.76。同时发现在不加催化剂NaOH的情况下,瓜尔胶在AmimCl中的羟丙基化反应同样可以发生,只是得到的HPG的MS相对较小。     

N,N-二乙基胺乙基取代瓜尔胶的合成及结构表征

在碱催化条件下,利用N,N-二乙基氯乙胺盐酸盐与瓜尔胶和羟丙基瓜尔胶一步法合成得到N,N-二乙基胺乙基瓜尔胶和N,N-二乙基胺乙基羟丙基瓜尔胶。结果显示合成过程中温度、反应时间、羟丙基取代度及溶剂等因素对产品分子量和N,N-二乙基胺乙基取代度有影响。通过红外光谱和核磁法对N,N-二乙基胺乙基瓜尔胶和羟丙基N,N-二乙基胺乙基瓜尔胶的分子结构进行了分析,并通过碳谱对N,N-二乙基胺乙基在瓜尔胶分子链中糖环上的取代分布进行了分析。     

羟丙基瓜尔胶中羟丙基摩尔取代度以及取代位置的表征

本文探索了表征羟丙基瓜尔胶(HPG)中羟丙基摩尔取代度(MS)以及取代位置的化学方法.当反应温度为110℃、反应时间为14h以及HPG中羟基与对甲苯磺酸-乙酸酐摩尔比为1:3.5时,用对甲苯磺酸-乙酸酐化学法和气相色谱法可准确测定HPG的羟丙基MS,与1H-NMR测定结果相对误差小于10%.在pH=10.30和0℃的条件下,瓜尔胶的伯羟基被2,2,6,6-四甲基哌啶氮--氧化物(TEMPO)-NaClO-NaBr体系选择性氧化成羧基,由此可表征羟丙基链段的取代位置.     

Hydrophobic guar gum derivatives prepared by controlled grafting processes

Introduction of polyalkoxyalkyleneamide grafts to guar gum produces a new water soluble guar derivative. Modification of either guar gum or hydroxyopropyl guar is achieved in a three‐step process: carboxymethylation with sodium chloroacetate, esterification with dimethyl sulfate (DMS) and amidation with a series of polyalkoxyalkyleneamines. The process was followed using infrared spectroscopy; the grafted guar derivatives were characterized using ¹H NMR. A series of hydroxypropyl guar (HPR) derivatives with degrees of carboxymethylations ranging from 0.2–0.3 were modified with polyalkoxyalkyleneamines with molecular weights ranging from 300 to 3000. The ratio of oxypropylene to oxoethylene units in the polyalkoxyalkyleneamines was varied from 9/1 to 8/58 to adjust the hydrophobicity of the grafts. Aqueous solutions of the graft copolymers exhibit viscosities one to two orders of magnitude lower than the corresponding solutions of the parent guar gum. Copyright © 2007 John Wiley & Sons, Ltd.     

Impact of Adding Polysaccharides on the Stability of Egg Yolk/Fish Oil Emulsions under Accelerated Shelf-Life Conditions

Polysaccharides can form interfacial complexes with proteins to form emulsions with enhanced stability. We assessed the effect of adding gum guar or gum arabic to egg yolk/fish oil emulsions. The emulsions were produced using simple or high-pressure homogenization, stored for up to 10 days at 45 °C, and characterized for their particle size and distribution, viscosity, encapsulation efficiency, oxidative stability, and cytotoxicity. Emulsions containing gum guar and/or triglycerides had the highest viscosity. There was no significant difference in the encapsulation efficiency of emulsions regardless of the polysaccharide used. However, emulsions containing gum arabic displayed a bridging flocculation effect, resulting in less stability over time compared to those using gum guar. Emulsions produced using high-pressure homogenization displayed a narrower size distribution and higher stability. The formation of peroxides and propanal was lower in emulsions containing gum guar and was attributed to the surface oil. No significant toxicity toward Caco-2 cells was found from the emulsions over time. On the other hand, after 10 days of storage, nonencapsulated fish oil reduced the cell viability to about 80%. The results showed that gum guar can increase the particle stability of egg yolk/fish oil emulsions and decrease the oxidation rate of omega-3 fatty acids.     

高碘酸钠氧化法测定羟丙基瓜尔胶上仲羟基取代度

高碘酸钠氧化可以使邻羟基C-C键发生高选择性断裂, 同时产生两分子醛基. 在pH=4.3及25 ℃的条件下, 对瓜尔胶及其衍生物羟丙基瓜尔胶进行高碘酸钠氧化, 采用红外光谱与核磁共振谱对氧化产物结构进行了表征. 结果表明, 氧化后的瓜尔胶和及羟丙基瓜尔胶结构中醛基主要以半缩醛的形式存在. 通过测定高碘酸钠的消耗量得到不同摩尔取代度羟丙基瓜尔胶糖单元上邻羟基的含量, 结合概率分析方法, 确定摩尔取代度分别为0.04, 0.14, 0.36, 0.51, 0.78, 1.05和1.53的羟丙基瓜尔胶在仲羟基上取代度分别为0.02, 0.09, 0.18, 0.30, 0.46, 0.59和1.03, 与其它方法得到的结果一致.     

Fast and excellent healing of hydroxypropyl guar gum/poly(N,N‐dimethyl acrylamide) hydrogels

In this article, a fast and high efficient healing hydroxypropyl guar gum (HPG)/poly(N,N‐dimethyl acrylamide) (PDMA) hydrogel is prepared by a facile synthesis method. HPG networks are formed through hydrogen‐bond interaction between the hydroxyl groups in the HPG chains, and PDMA networks are self‐crosslinked without any chemical crosslinker. The cut hydrogel could heal when nanosilica solution is chosen as the connector that is related to the adsorption of polymer to the surface of nanosilica. The fracture stress of the HPG/PDMA gels presents a fast and almost full recovery within a short time (1 min), while the recovery of fracture strain and elastic modulus is related to time in 2 h. The healing efficiency of HPG/PDMA gel is investigated as a function of healing time, HPG content, and N,N‐dimethyl acrylamide content. The microscopic healing process and healing mechanism are also discussed. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 239–247     

Photo-induced Synthesis and Characterization of Poly（methyl methacrylate） Grafted Sodium Salt of Partially Carboxymethylated Guar Gum

Photo-induced graft copolymerization of methyl methacrylate（MMA） onto sodium salt of partially carboxymethylated guar gum（Na-PCMGG, DS = 0.291） was carried out in an aqueous medium using ceric ammonium nitrate（CAN） as photoinitiator to synthesize a novel graft copolymer, Na-PCMGG-g-PMMA, which may find its potential application as a metal adsorbent. The influences of synthesis variables such as concentrations of photoinitiator（CAN）, nitric acid and monomer（MMA） as well as reaction time, temperature and amount of substrate on the grafting yields were studied and the reaction conditions for optimum photo-grafting were evaluated. At optimum concentration, the maximum values of the grafting yields achieved were G = 271.61% and GE = 63.89%. The experimental results were found to be in very good agreement with the proposed kinetic scheme. The photo-graft copolymerization of MMA onto Na-PCMGG（ DS = 0.291） was also carried out in the presence and absence of ultraviolet radiation for studying the efficiency of the photoinitiator. The influence of carboxymethyl groups introduced onto the guar gum molecules with regard to its behavior towards ultra-violet radiation induced grafting with MMA was also investigated. Photo-grafting process was confirmed and the products were characterized with the help of the spectroscopic（1H-NMR and FTIR） and SEM techniques.