pH值调控构建的纳米Ni-W催化剂用于纤维素氢解制多元醇的研究

采用等体积浸渍法制备了双金属Ni-W催化剂，并研究了制备过程中前驱体溶液pH值对活性的影响。柠檬酸和氢氧化钾分别作为酸碱调节剂将前驱体溶液pH值调节至0.83、1.00、3.09、5.00、7.03、8.97和11.0。纤维素氢解反应结果表明，当前驱体溶液的pH值为1.00时，在氢压为5.0 MPa、温度为518 K的反应条件下，得到低碳（C_2，3）多元醇的总收率为74.5%。此外，通过BET和SEM表征了催化剂的物理性质。其比表面积为330-450 m²/g，且在高温煅烧下SBA-15仍保持良好的水热稳定性。TEM和SEM-EDX结果显示，催化剂粒子在载体表面分散性较好，但也有少量的聚集现象。XRD表征表明，NiO等物种的还原程度明显受到pH值的影响，且镍、钨物种的相态也存在着显著不同。     

多元醇一步法制备高碳烃液体燃料的研究

在较温和的条件下,山梨醇和木糖醇被氢碘酸还原转化为高碳烃液体燃料。产物采用GC-MS和FT-IR进行定量分析与表征,并对高碳烃产品的理化性质进行了测定。结果表明,以山梨醇为原料制备的高碳烃产物主要是包括C12H16、C12H18、C12H20、C12H22和C18H26在内的烷烃、烯烃和芳香烃等化合物,烃类的总产率可达85.1%。以木糖醇为原料的反应过程与山梨醇相似,但所得高碳烃是以C10和C15为主的烃类化合物,产率为62.8%。实验还以质量分数为50%的山梨醇和50%的木糖醇混合物为原料制备了高碳烃,结果发现,产物中除C10、C12、C15和C18烃外,还有一定量的C11烃生成,高碳烃产率为65.4%。反应产物经碱化、旋转蒸发和减压蒸馏后分离得到纯度较高的高碳烃,其含水量低于0.2%,常温下运动黏度为3.15~3.17 mm2/s,密度为0.830~0.840 g/mL,含氧量为1.8%~2.1%,热值高于43 MJ/kg。高碳烃的生成是由于多元醇被还原过程中C-I键的极性反转和分子间C-C键的偶联导致。     

聚酯的序列结构对聚氨酯弹性体形貌的影响

以己二酸(AA),1,4-丁二醇(BDO),乙二醇(EG)分别采用一步法、二步法合成分子量为3000的聚酯PAEB-R和聚酯PAEB-A.再分别与二苯基甲烷二异氰酸酯(MDI)、扩链剂1,4-丁二醇(BDO),乙二醇(EG)反应分别合成固含量30%与粘度为20000的聚氨酯(PAEB-R)-MDI-TPU和聚氨酯(PAEB-A)-MDI-TPU.SEM、AFM表明不同工艺所合成的聚氨酯均存在微相分离,且聚氨酯(PAEB-R)-MDI-TPU微相分离程度高于(PAEB-A)-MDI-TPU.     

聚酯多元醇的序列结构对热塑性聚氨酯弹性体的性能影响

以己二酸(AA),1,4-丁二醇(BDO),乙二醇(EG)为原料,分别采用一步法、二步法合成分子量为3 000的聚酯PAEB-R和聚酯PAEB-A。差示扫描量热仪(DSC)、广角X射线衍射(WAXS)表明PAEB-A为有序的,聚酯PAEB-R为无序的。聚酯PAEB-R和聚酯PAEB-A再分别与二苯基甲烷二异氰酸酯(MDI)、扩链剂1,     

生物质利用新途径:多元醇催化合成可再生燃料和化学品

日益严重的全球性能源和环境问题促使开发利用可再生的生物质资源成为当前研究的一个热点.本文概述了生物质基多元醇合成燃料和化学品来实现生物质转化利用的一些最新进展,特别是集中介绍了甘油和山梨醇等多元醇催化水相重整合成氢气和液体烃等燃料、催化选择氢解和氧化合成高附加值化学品或化学中间体等方面的进展,分析了存在的问题和可能的解决措施以及今后的发展趋势,指出生物质基多元醇将成为今后合成可再生燃料和化学品的新型平台分子.     

High Bio-Content Thermoplastic Polyurethanes from Azelaic Acid

To realize the commercialization of sustainable materials, new polymers must be generated and systematically evaluated for material characteristics and end-of-life treatment. Polyester polyols made from renewable monomers have found limited adoption in thermoplastic polyurethane (TPU) applications, and their broad adoption in manufacturing may be possible with a more detailed understanding of their structure and properties. To this end, we prepared a series of bio-based crystalline and amorphous polyester polyols utilizing azelaic acid and varying branched or non-branched diols. The prepared polyols showed viscosities in the range of 504–781 cP at 70 °C, with resulting TPUs that displayed excellent thermal and mechanical properties. TPUs prepared from crystalline azelate polyester polyol exhibited excellent mechanical properties compared to TPUs prepared from amorphous polyols. These were used to demonstrate prototype products, such as watch bands and cup-shaped forms. Importantly, the prepared TPUs had up to 85% bio-carbon content. Studies such as these will be important for the development of renewable materials that display mechanical properties suitable for commercially viable, sustainable products.     

Strategy of Controlling Ru Particles Size for Regulating Cleavage Rate of C−C and C−O Bonds of Biomass Polyols to Enhance the Yield of Methane

A series of porous silica were prepared by alkyl-trimethyl-ammonium bromide with different carbon chain lengths (PS-n, n corresponds to the carbon chain length). These templates carried out precise structure regulation of porous silica. The Ru particles supported on porous silica behaved in precisely controlled size according to the pore diameter. When used in the hydrogenolysis of biomass polyols, a higher methane yield was achieved over Ru/PS-16. This result can be explained by the higher C₂/C₃ over Ru/PS-16 than others.     

Selective hydrolysis of anti-1,3-diol-acetonides for the differentiation of 1,3-anti and 1,3-syn diols

A mild and general method for the selective cleavage of anti-1,3-acetonides has been developed for the differentiation of 1,3-anti and 1,3-syn diols in long chain polyolic fragments. The diluted acidic conditions applied to these systems are compatible with other common protecting groups such as silyl ethers and benzyloxymethyl ethers.     

Diffusion of polyols in aqueous solution

The diffusion coefficients of aqueous solutions of the polyols CH₂OH-(CHOH)₄-CH₂OH (dulcitol, sorbitol, and myo-inositol) have been determinated using the Gouy interferometric method. Viscosity and density measurements have been carried out at the same temperature and concentration range for these and for mannitol. The concentration dependence of the diffusion coefficients are discussed in terms of solute-solute interactions with the help of thermodynamic literature data. Among the studied polyols, only dulcitol and myo-inositol exhibit a strong evidence for solute-solute interaction, whereas the other shows a preferential interaction with the solvent.     

Steroid compounds from the starfish Lysastrosoma anthosticta collected in the Sea of Japan

Six polyhydroxylated steroids and their derivatives were isolated from the starfish Lysastrosoma anthosticta collected in the Posyet Bay, Sea of Japan. These include a new glycoside of the steroid polyol, lysastroside A (1), which was identified as (25S)-26-O--d-xylopyranosyl-5-cholestane-3,6,8,15,16,26-hexaol, and the previously known pycnopodioside C monoglycoside (2), marthasterone sulfate (3), (25S)-5-cholestane-3,6,8,15,16,26-hexaol (4), (25S)-5-cholestane-3,6,7,8,15,16,26-heptaol (5), and (25S)-5-cholestane-3,6,7,8,15,16,26-heptaol (6). The compounds were tested for the haemolytic activity and the action on the embryogenesis of the sea urchin Strongylocentrotus intermedius.