固体酸催化合成异山梨醇的研究

以对甲苯磺酸为催化剂、甲苯为带水剂,山梨醇脱水制备异山梨醇,产品质量符合日本药典XV质量标准,收率约为50%。     

载体型固体酸催化制备异山梨醇

采用不同的载体,制备了多种固体酸催化剂,并对其催化山梨醇脱水的反应活性进行了研究,进一步对催化效果较好的固体酸进行反应条件优化,考察了催化剂用量、反应压力、反应温度和反应时间对山梨醇脱水反应的影响。结果表明,以活性炭为载体的固体酸催化剂催化性能较好。在反应压力为6.3 k Pa,催化剂和山梨醇质量比为1:4,温度为140℃,山梨醇脱水反应6 h的条件下,异山梨醇的收率较高,为91.0%。     

2-醋酸异山梨醇酯的合成研究

由山梨醇经脱水、酯化而合成了2-醋酸异山梨醇酯,山梨醇脱水收率达70%,酯化过程分别采用了乙酸和乙酸酐作为酰化剂进行酯化反应.酯化产物经处理后,2-醋酸异山梨醇酯纯度可达85%,经重结晶纯度为97.7%.     

5-单硝酸异山梨醇酯的合成研究(Ⅱ)

山梨醇经脱水、酯化、硝酸酯化及皂化,合成了５ 单硝酸异山梨醇酯。山梨醇脱水反应：山梨醇与硫酸质量比为１∶００１４,二甲苯作带水剂,反应温度１４０℃,反应时间３５ｈ,得异山梨醇（Ⅰ）,收率６９％;酯化反应：异山梨醇、冰乙酸及对甲基苯磺酸的质量比为１∶０４９∶００３４,溶剂Ｓ兼作带水剂,回流反应,得２ 乙酸异山梨醇酯混合物（Ⅱ）;在１０℃,Ⅱ与硝酸质量比为１∶０３６,２ｈ内进行硝酸酯化,得２ 乙酸 ５ 硝酸异山梨醇酯混合物（Ⅲ）;Ⅲ在５０℃、ｐＨ＝１０～１２条件下皂化１５ｈ,得５ 单硝酸异山梨醇酯。总收率２５％。     

5—单硝酸异山梨醇酯的合成研究（II）

山梨醇经脱水，酯化，硝酸酯化及皂化，合成了５－单硝酸异山梨醇酯，山梨醇脱水反应：山梨醇与硫酸质量比为１：０．０１４，二甲苯作带水剂，反应温度１４０℃，反应时间３．５ｈ，得异山梨醇（Ｉ）收率６９％，酯化反应：异山梨醇，冰乙酸及对甲基苯磺酸质量比为１：０．４９：０．０３４，溶剂Ｓ兼作带水剂，回流反应，得２－乙酸异山峰果醇酯混合物（ＩＩ），在１０℃，Ⅱ与硝酸质量比为１：０．３６，２ｈ内进行硝酸酯化，得２     

异山梨醇的制备及应用研究

近年来,随着化石资源的日益枯竭,对生物质及其衍生物的研究越来越受到人们的重视.异山梨醇作为一种新型的生物基化工原料,可以应用于医药、高分子材料、液晶、增塑剂等领域.阐述了近几年来异山梨醇的制备及应用研究进展.     

异山梨醇化学结构确证

对采用一次高真空蒸馏 ,粉状活性炭吸附得到的异山梨醇成品 ,进行了紫外光谱、红外光谱、质谱、核磁共振氢谱和碳谱测定。经波谱解析确证了异山梨醇的化学结构为 1,4;3 ,6 二脱水 D 山梨醇     

异山梨醇化学结构确证

对采用一次高真空蒸馏，粉状活性炭吸附得到的异山梨醇成品，进行了紫外光谱，红外光谱，质谱，核磁共振氢谱和碳谱测定，经波谱解析确证了异山梨醇的化学结构为1，4：3，6－二脱水－D－山梨醇。     

山梨醇杂质对异山梨醇型聚碳酸酯聚合的影响

异山梨醇型聚碳酸酯(PIC)是一类理想的可替代传统双酚A型聚碳酸酯(BPA-PC)的生物基聚碳酸酯,具有广泛的应用前景。然而,异山梨醇(IS)中的痕量杂质会干扰聚合反应,导致产物分子量低、易黄变,产业化应用受到严重制约。探究杂质对PIC聚合的影响可为其性能优化提供思路。以异山梨醇和碳酸二苯酯(DPC)作为原料,乙酰丙酮锂作为催化剂,通过熔融酯交换缩聚法成功制备了PIC,黏均分子量■达40 180,玻璃化转变温度(T_g)可高达174℃。通过反向添加法结合碳酸酯交换反应动力学探究了山梨醇杂质对PIC聚合的影响。结果表明,山梨醇的存在会显著降低PIC的聚合反应速率(k’)和分子量,山梨醇含量为异山梨醇及杂质物质的量总量的1%时,■降低了22 042。并且随着山梨醇含量的增多,PIC由淡黄色逐渐变成棕黑色。此外,山梨醇的增多会使PIC的T_g以及热稳定性出现轻微的下降现象。     

酸催化山梨醇脱水制异山梨醇的研究进展

异山梨醇是一种生物基功能性二元醇,近年来因其在聚合物工业中的潜在应用价值而备受关注。山梨醇脱水反应是生物质转化合成异山梨醇的关键步骤,目前普遍采用酸催化体系,且在酸性催化剂开发及工艺研究方面均取得了良好进展。本工作主要介绍了已报道的酸性催化剂结构与性质对催化活性及选择性的影响,指出强酸性均相催化剂具有高催化活性,但腐蚀性强,且不易循环利用;多相催化剂催化活性与酸性位点、酸度、酸容量、孔结构、表面性质和结构等都有关系,且这些性质随催化剂组成和结构改变而相互影响。针对目前山梨醇脱水反应催化剂均相催化腐蚀性强、催化剂循环性差,多相催化剂催化活性不高的现状,高催化活性可循环使用的离子液体催化剂是一种具有发展潜力的均相催化剂,对多相催化剂构效关系还应进行更多的研究以指导新型催化剂的开发。     

H3PW12O40/SiO2 for sorbitol dehydration to isosorbide: High efficient and reusable solid acid catalyst

Tungstophosphoric acids (PW) supported on various metal oxides (SiO₂, γ-Al₂O₃, TiO₂, ZrO₂ and CeO₂) were synthesized and used as catalysts for sorbitol dehydration to isosorbide for the first time. 30% PW/SiO₂ exhibited the best catalytic performance for sorbitol dehydration, over which 56% isosorbide selectivity could be gained at a 95% sorbitol conversion at 250 °C. The catalytic performance of regenerated 30% PW/SiO₂ catalysts by dichloromethane elution showed no loss after recycling five runs. Characterizations with UV-Vis, XRD, NH₃-TPD and thermal analysis techniques revealed that PW had a good dispersion, and the primary Keggin structure was preserved after supporting PW on different supports. The interaction between PW and oxides resulted in different acidity of catalysts, which affected conversion of sorbitol and selectivity for isosorbide. The final acidity order of supported PW catalysts was the following: SiO₂>γ-Al₂O₃>TiO₂ ≈ ZrO₂>CeO₂.     

Arenesulfonic acid functionalized ordered mesoporous silica as solid acid catalyst for solvent free dehydration of sorbitol to isosorbide

Organosulfonic acid functionalized ordered mesoporous silicas with different moieties have been synthesized and used as solid acid catalysts for solvent free dehydration of sorbitol to isosorbide. In screening experiments with distinct solid acids, the arenesulfonic acid functionalized SBA-15 (Ar/SBA-15) showed higher catalyst performance as compared to propyl and fluorosulfonic acid sites. Under optimum reaction condition, Ar/SBA-15 afforded 100% sorbitol conversion with 71% isosorbide selectivity in 2 h at moderate temperature of 170 °C. The high activity of catalyst ascribed to its ordered mesoporous structure and ease to access Brönsted acid sites with high acid strength.     

Solubilizing and Hydrotropic Properties of Isosorbide Monoalkyl- and Dimethyl-Ethers

Isosorbide is a diol readily obtained from starch that can be used as a polar building block for the synthesis of derivatives ranging from solvents to surfactants: dimethyl isosorbide (DMI) is a “sustainable solvent” already on the market, used notably in cosmetic and pharmaceutical formulations; monoalkyl derivatives of isosorbide are non-ionic hydrotropes that could be potential substitutes to short-chain glycol ethers. The use of these isosorbide derivatives as bio-sourced alternatives to petroleum-derived products for applications such as compatibilizers in liquid detergent formulations or solubilizing agents in aqueous hard-surface cleaning is discussed in this paper. DMI reveals to have interesting coupling properties for the former applications, whereas the monopentyl ether of isosorbide (C₅Iso) is a particularly efficient hydrotrope for the latter.     

Isosorbide Production from Sorbitol over Heterogeneous Acid Catalysts: Screening and Kinetic Study

The catalytic performance of two types of heterogeneous acid catalysts—sulfonic acid-functionalized materials and aluminum containing zeolites,—in the dehydration of sorbitol to isosorbide, in solventless and autogenous pressure conditions, has been studied. Catalysts screening evidenced strong differences between sulfonic acid-based materials and acid zeolites in terms of catalytic performance. Whereas sulfonic materials, such as Amberlyst-70 and SBA-15-Pr-SO₃H, showed a very high catalytic activity, zeolites with beta structure evidenced good catalytic performance together with minimized promotion of side reactions (production of non-desired sorbitans, humins, etc.). Kinetic studies performed at different temperatures, adjusting to a Langmuir–Hinshelwood type model, allowed correlating the physicochemical properties of the acid materials with their catalytic performance in sorbitol dehydration. Thus, the analysis of initial selectivity through kinetic constants comparison indicated that commercial beta zeolite with a Si/Al ratio of 19 is the most selective catalyst for the production of isosorbide, though following a slower kinetics than the sulfonic materials. Furthermore, an equivalent hierarchical beta zeolite has been synthesised and evaluated, resulting in a slight improvement of the catalytic performance, in terms of both yield and selectivity to isosorbide. This improvement is attributed to the superior textural properties.     

Sulfated tin oxide as an efficient solid acid catalyst for liquid phase selective dehydration of sorbitol to isosorbide

Sulfated tin oxides (STO) with different sulfur content (1–8 wt%) were prepared via straightforward thermal decomposition of stannous sulfate. The catalyst performances of STO were investigated in liquid phase dehydration of sorbitol under solvent free condition. The calcination temperature of STO affected sulfur content and isosorbide selectivity. The STO exhibited high catalytic activity compared to sulfated zirconia affording complete conversion of sorbitol with 65% isosorbide selectivity in 2 h at 180 °C. Effects of reaction temperature, catalyst amount and reaction time on conversion and selectivity were studied and the catalyst was also reused.     

The effect of P/Ta ratio on sorbitol dehydration over modified tantalum oxide by phosphoric acid

A series of modified hydrated tantalum oxides (Ta₂O₅·nH₂O) with various contents of phosphoric acid were prepared and firstly used as the catalysts for sorbitol dehydration to isosorbide. The catalytic performance of Ta₂O₅ was improved significantly after modification, and the isosorbide selectivity over 0.8P/TaO was improved from 3.8 to 48.3% with nearly 100% sorbitol conversion. Characterization with NH₃-TPD, FT-IR, Raman and XRD demonstrated that the introduction of phosphate has transformed Ta₂O₅ into two kinds of new crystalline phases exhibiting various surface acidities. The P-OH species in TaH(PO₄)₂ were mainly responsible for the promotion of catalytic performance over modified oxides.     

Thermoplastic polyurethanes with controlled morphology based on methylenediphenyldiisocyanate/isosorbide/butanediol hard segments

Isosorbide, a cyclic, rigid and renewable diol, was used as a chain extender in two series of thermoplastic polyurethanes (PUs). Isosorbide was used alone or in combination with butanediol to examine the effects on the morphology of PU. Two series of materials were prepared – one with dispersed hard domains in a matrix of polytetramethylene ether glycol soft segments of molecular weight 1400 g mol^?1 (at 70 wt% soft segment concentration, SSC) and the other with co‐continuous soft and hard phases at 50 wt% SSC. We investigated the detailed morphology of these materials with optical and atomic force microscopy, as well as ultra‐small‐angle X‐ray scattering. The atomic force microscopy measurements confirmed the different morphologies in PUs with 50 wt% SSC and with 70 wt% SSC. Small‐angle X‐ray scattering data showed that in PU with 70 wt% SSC, the hard domain size varied between 2.4 and 2.9 nm, and decreased with increasing isosorbide content. In PU with 70 wt% SSC, we found that the correlation length and average repeat distances became smaller with increasing isosorbide content. We estimated the thickness of the diffuse phase boundary for PU with 70 wt% SSC to be ca 0.5 nm, decreasing slightly with increasing isosorbide content. © 2015 Society of Chemical Industry     

Lipase-Catalysed Esterification Reactions—Experimental and Modelling Studies

A comparative study of supported lipozyme-catalysed esterification of oleic acid with lauryl alcohol, isosorbide and sorbitol in a packed tubular reactor is described. The reaction rate was highest with lauryl alcohol, followed by isosorbide and sorbitol. The esterification reaction between oleic acid and lauryl alcohol was carried out in a tubular recycle reactor and a stirred reactor. Different strategies were used to remove the water formed during the reaction. The rate was found to be highest in the tubular reactor. The reactions were modelled by three bisubstrate models, namely ternary complex random order, Ping-Pong, and Ping-Pong with competitive product inhibition. The third model was found to predict the observed behaviour. © 1997 SCI.     

Effect of preparation method on the structure and catalytic property of activated carbon supported nickel oxide catalysts

A series of activated carbon (AC) supported nickel oxide (NiO) catalysts were prepared by aqueous reduction preparation methods with nickel nitrate as a precursor. The effects of preparation procedure and reducing agent on catalyst structure and catalytic property were investigated. Based on the information obtained from physico-chemical characterizations and sorbitol dehydration performances, preparation methods were found to have a significant influence on NiO distribution and surface acidity. The catalysts prepared through the simultaneous loading-reduction procedure had stronger acidity and higher NiO dispersion on the outer surface of AC, which contributed jointly to high sorbitol conversion (turn-over frequency of 190–240 h^?1) and slightly low selectivity to anhydro sugar alcohols (ca. 66%). Correspondingly, with the procedure of reduction of supported nickel catalyst precursors, the selectivity to anhydro sugar alcohols was improved by ca. 10%, while sorbitol conversion was quite low (ca. 20%). Reducing agent exerted less influence on the structure compared with preparation procedure. However, when the simultaneous loading-reduction procedure was used, sodium borohydride influenced the acidity remarkably by formation of a new strong acid site, resulting in better dehydration performances.