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991.
Hydrophobic mesoporous acidic resin for hydroxyalkylation/alkylation of 2‐methylfuran and ketone to high‐density biofuel 下载免费PDF全文
Xiangwen Zhang Qiang Deng Peijuan Han Jisheng Xu Lun Pan Li Wang Ji‐Jun Zou 《American Institute of Chemical Engineers》2017,63(2):680-688
Hydroxyalkylation/alkylation of biomass‐derived 2‐methylfuran with cyclic ketones (cyclopentanone and cyclohexanone) has great potential in synthesizing high‐density biofuel. But the conversion and selectivity are still unsatisfactory because the in‐situ formed water decreases the acidity of catalyst and induces side reaction. Herein, hydrophobic mesoporous resins with sulfonic acid group (PS) and fluoride sulfonic acid group (PCS) were synthesized by a simple solvothermal reaction and ion exchange treatment, which have good mesoporous structure with surface area of 300–700 m2/g. Notably, PS and PCS have better hydrophobicity and oleophilicity as compared to widely used sulfonic acid functional amberlyst‐15 and fluoride sulfonic acid functional nafion‐212. In the hydroxyalkylation/alkylation reaction, PS shows higher activity and selectivity than amberlyst‐15 while PCS surpasses nafion‐212. Furthermore, both PS and PCS have good recycling stability in consecutive 5 runs. After hydrodeoxygenation, two high‐density biofuels with density of 0.819 and 0.825 g/mL were obtained. © 2016 American Institute of Chemical Engineers AIChE J, 63: 680–688, 2017 相似文献
992.
Glycidyl methacrylate (GMA) functionalized methyl methacrylate-butadiene-styrene core-shell particles (PB-g-MSG) were prepared to toughen poly (butylene terephthalate) (PBT) and polycarbonate (PC) blends. T-dodecyl mercaptan (TDDM) was used to modify the grafting character of the core-shell particles. The addition of TDDM decreased the grafting degree, particles size and crosslinking degree of PB-g-MSG particles. At the same time, the free methyl methacrylate-co-styrene-co-glyceryl methacrylate copolymer (f-MSG) increased. The f-MSG reacted with PBT and suppressed the transesterification between PBT and PC. On the other hand, f-MSG promoted the crystallization of PBT by heterogeneous nucleation. When the TDDM content was lower than 0.76%, PB-g-MSG particles dispersed in the matrix uniformly, otherwise, agglomeration took place. The change of TDDM content in the PB-g-MSG particles influenced the toughening ability and tensile properties. When the TDDM content was 0.76%, the PBT/PC/PB-g-MSG blend showed the optimum impact toughness and yield strength, which are 908 J/m and 49.4Mpa. Fracture mechanism results indicated that cavitation induced shear yielding occurred in the PBT/PC/PB-g-MSG blend when no TDDM addition for the core-shell particles. With the addition of TDDM, the interfacial strength decreased between the PB-g-MSG core-shell particles and the matrix. So voids appeared due to debonding, which also could promote the shear yielding process. 相似文献
993.
Zhengyu Gong Fangfang Niu Guoping Zhang Jinhui Li Gang Li Wangping Huang Hai Deng Rong Sun Chingping Wong 《Journal of Polymer Research》2017,24(8):127
In previous work, we have developed a dual physically cross-linked hydrogel composed of poly (acrylamide-co-acrylic acid) (PAM-co-PAA) and polyvinyl alcohol (PVA), named as PVA/CP DN gel, by facile copolymerization and freezing/thawing. The PVA/CP DN gel is featuring both excellent mechanical properties and self-healing ability. Additionally, we have preliminarily found that the comonomer ratio for PVA/CP DN gel have great influence on the self-healing efficiency. In this research article, we will further discuss the mechanical and self-healing properties of the PVA/CP DN gel by varying the comonomer ratio of PAM-co-PAA. The results proved that the structure of DN will be loosen when the number of PAA segments exceed that of PAM. More PAA segments in copolymer make the PVA/CP DN gel have better elongation at break but weak in tensile strength and young’s modulus because of less PVA crystalline domains formed in the gel. The energy dissipation value for the double-network hydrogel decrease with the addition of PAA segments, whereas self-healing efficiency of PVA/CP DN gel increased. Anyway, this work provides more information to further understand the effects of composition on the properties of dual physically cross-linked PVA/CP DN hydrogel. 相似文献
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目的建立槲皮素胶囊在四种溶出介质中溶出度的测定方法,考察表面活性剂十二烷基硫酸钠对槲皮素溶出度的影响。方法制备槲皮素对照品胶囊及含十二烷基硫酸钠的水飞蓟样品胶囊,采用桨板法,转速为100 r·min~(-1),用紫外分光光度法分别测定槲皮素对照品胶囊与槲皮素样品胶囊在四种溶出介质中的溶出度。结果在pH1.2和pH4.0缓冲溶液的溶出介质中,槲皮素样品胶囊的溶出度小于槲皮素对照品胶囊;在蒸馏水和pH6.8缓冲溶液的溶出介质中,槲皮素样品胶囊的溶出度大于槲皮素对照品胶囊。结论在偏碱性的条件下,十二烷基硫酸钠对槲皮素具有增溶作用。 相似文献
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众所周知,纤维素材料可从各种自然资源中获得,并且可以作为廉价的吸附剂被广泛应用。通过化学改性,纤维素基吸附剂对重金属离子和其他水体污染物的吸附能力可以显著提高。各种矿物和有机酸、碱、氧化剂、有机化合物等化学物质已被用于纤维素改性中。本文综述了纤维素材料的使用,包括天然状态、改性状态和它们去除各种污染物的效力等。从本文提供的文献调查,改性纤维素基吸附剂具有良好的潜力应用于各种水体污染物的去除,然而,仍然有必要找出这些吸附剂的商业实用性,以便改进在污染控制的应用价值。 相似文献
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