共查询到14条相似文献,搜索用时 78 毫秒
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电膜法生产木糖醇工艺 总被引:3,自引:0,他引:3
电膜法生产木糖醇工艺黄玉秀(华南理工大学应用化学系广州510641)关键词木糖,木糖醇,制备,电还原法1996-09-10收稿,1997-01-23修回目前生产木糖醇都用高压加氢法[1,2].此法工艺流程长,对设备要求高,生产不安全.应用电膜法生产木... 相似文献
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淀粉与木糖醇共混物的性能 总被引:10,自引:0,他引:10
淀粉与木糖醇共混物的性能于九皋,郑华武(天津大学化学系天津300072)关键词淀粉,木糖醇,共混,热塑性研究具有环境条件下可降解的塑料已成为国内外专家学者广泛关注的研究课题。淀粉具有类似高聚物的分子结构,但由于分子量大,分子之间的亲合力强,很难加工成... 相似文献
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应用精密数字密度计测定了298.15 K时甘氨酸、L-丙氨酸或L-缬氨酸与不同组成的木糖醇-水混合溶剂构成的三元系溶液的密度, 计算了氨基酸的表观摩尔体积、极限偏摩尔体积、迁移偏摩尔体积和水化数. 根据结构水合作用模型讨论了迁移偏摩尔体积和水化数的变化规律. 结果表明, 氨基酸两性离子部分与木糖醇羟基间的相互作用占主导地位, 且随木糖醇浓度的增大而增大. 氨基酸在木糖醇水溶液中的迁移偏摩尔体积为正值, 甘氨酸的迁移偏摩尔体积大于L-丙氨酸和L-缬氨酸的. 氨基酸在木糖醇水溶液中的水化数随溶液中木糖醇浓度的增加而减小. 相似文献
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毛细管区带电泳法分离发酵液中的木糖和木糖醇 总被引:1,自引:0,他引:1
建立了利用毛细管区带电泳分离发酵液中木糖和木糖醇的新方法。研究表明 :采用硼砂缓冲溶液时 ,木糖和木糖醇的分离度随硼砂浓度的增高而加大 ,在室温下硼砂最高浓度为 130mmol/L ;分离度还与溶液的 pH有关 ,在pH 9 5 5处分离度有最大值 ;缓冲液中十六烷基三甲基溴化铵的浓度为 4× 10 -6mmol/L~ 8× 10 -4 mmol/L时对分离度无显著影响 ;在优化的分离条件下 ,木糖和木糖醇可在 6min内基线分离。测定了发酵过程中样品各组分的含量和加标回收率 ,5次测定木糖的相对标准偏差 (RSD)为 1 42 %~ 3 11% ,回收率为 96 0 %~ 10 8 0 % 。 相似文献
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用高效液相色谱法测定木瓜素中木糖醇的方法,采用Waters碳水化合物柱(4.6 mm×250 mm),用乙腈∶水(85∶15)作为流动相,示差检测器检测.该方法平均回收率为99.0%,RSD为2.2%,操作简便,结果满意. 相似文献
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合成了三类磺酸功能化离子液体,通过STA、DSC-TG、UV-Vis、运动粘度/密度计等手段考察了离子液体的热力学性质、酸度、粘度和密度等理化性质,发现离子液体阴阳离子的结构对这些理化性质有不同程度的影响,并对离子液体的结构与理化性质变化关系进行初步探讨. 相似文献
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Qi Xia Xin Jin Guangyu Zhang Mengyuan Liu Jinyao Wang Yushan Li Tianqi Fang Jie Ding Dongpei Zhang Kexin Meng Xiaobo Chen Chaohe Yang 《Chemical record (New York, N.Y.)》2021,21(1):133-148
Xylitol is commonly known as one of the top platform intermediates for biomass conversion. Catalytic deoxygenation of xylitol provides an atomic and energetic efficient way to produce a variety of renewable chemicals including ethylene glycol, 1,2‐propanediol, lactic acid and 1,4‐anhydroxylitol. Despite a few initial attempts in converting xylitol into those products, improving catalyst selectivity towards C?O and C?C cleavage reactions remains a grand challenge in this area. To our best knowledge, there is lack of comprehensive review to summarize the most recent advances on catalyst design and mechanisms in deoxygenation of xylitol, offering important perspective into future development of xylitol transformation technologies. Therefore, in this mini‐review, we have critically discussed the conversion routes involved in xylitol deoxygenation over solid catalyst materials, the nanostructures of supported metal catalysts for C?H, C?C and C?O bond cleavage reactions, and mechanistic investigation for xylitol conversion. The outcome of this work provides new insights into rational design of effective deoxygenation catalyst materials for upgrading of xylitol and future process development in converting hemicellulosic biomass. 相似文献
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Christine Bonal Jean-Pierre Morel Nicole Morel-Desrosiers 《Journal of solution chemistry》1998,27(4):361-372
The apparent equilibrium constants and enthalpies of complexation of Nd3+, Sm3+, Eu3+, and Gd3+ by xylitol in aqueous solutions containing NaNO3 at an ionic strength of 2.0 mol-kg–1 have been determined by microcalorimetry at 25°C. Since nitrate anion weakly complexes the lanthanide cations, these values are analyzed in terms of competition between xylitol and NO
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The method leads to the apparent equilibrium constants and enthalpies of complexation of the lanthanide cations by NO
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at this particular ionic strength. Despite the difficulties encountered in characterizing rather weak associations, the results are, whenever comparison is possible, in good agreement with those obtained by direct microcalorimetry. The advantage of this competition method is that it can be used when the enthalpic effects are too weak and insufficiently concentration dependent for direct microcalorimetric determination. In the present case, it allows us to thermodynamically characterize the formation of SmNO
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and EuNO
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, processes we have not been able to study directly. 相似文献
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微型毛细管电泳安培检测无糖口香糖中的木糖醇和山梨醇 总被引:1,自引:0,他引:1
采用微型的毛细管电泳-安培(CE-AD)测定装置对市售的3种无糖口香糖中的木糖醇和山梨醇的测定进行了研究。实验采用铜盘工作电极,在0.65V的检测电位下,用70mmol/L NaOH缓冲溶液,4kV的分离电压,木糖醇和山梨醇在10min之内实现了良好的分离,其中木糖醇的线性范围为5×10-5~1×10-2mol/L,山梨醇的线性范围为5×10-5~5×10-2mol/L(r>0.9997),检出限分别为5×10-6mol/L和2.5×10-6mol/L。该方法测定样品中木糖醇和山梨醇的相对标准偏差和回收率分别为3.7%、4.5%和98.1%、91.1%(n=10)。将该方法用于好丽友口香糖、益达口香糖、华艾康口香糖中木糖醇和山梨醇的测定,结果令人满意。 相似文献
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Lilian Mussi Andr Rolim Baby Flavio Bueno Camargo Junior Giovana Padovani Bianca da Silva Sufi Wagner Vidal Magalhes 《Molecules (Basel, Switzerland)》2021,26(21)
In addition to dermatological complications, acne can affect the quality of life of individuals in numerous ways, such as employment, social habits and body dissatisfaction. According to our expertise, caprylic acid and propanediol would not have a direct action on Cutibacterium acnes. Despite this, we investigated the existence of a synergistic effect among xylitol, caprylic acid and propanediol as a mixture of compounds representing a single topical active ingredient that could benefit the treatment against acne. In vitro and in vivo assays were performed to challenge and to prove the efficacy of propanediol, xylitol and caprylic acid (PXCA) against acne. PXCA had its MIC challenged against C. acnes (formerly Propionibacterium acnes) and Staphylococcus aureus, resulting in concentrations of 0.125% and 0.25%, respectively, and it also developed antimicrobial activity against C. acnes (time-kill test). PXCA was able to reduce the 5-alpha reductase expression in 24% (p < 0.01) in comparison with the testosterone group. By the end of 28 days of treatment, the compound reduced the skin oiliness, porphyrin amount and the quantity of inflammatory lesions in participants. According to the dermatologist evaluation, PXCA improved the skin’s general appearance, acne presence and size. 相似文献