• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Design of non-fluorous carbon dioxide soluble compounds.
【24h】

Design of non-fluorous carbon dioxide soluble compounds.

机译：设计无氟二氧化碳可溶化合物。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Supercritical carbon dioxide (scCO2) is an environmental friendly solvent for various chemical processes. In many cases scCO2 is unable to replace organic solvents due to the low solubility of most polar and ionic materials in dense CO2. Highly CO2 soluble fluorinated polymers have been successfully designed but they are expensive and environmentally persistent. This project aims developing a non-fluorous compound which dissolves in CO2 and thickens CO2, thereby improving the performance CO2 flooding enhanced oil recovery.;An attempt was made to generate CO2-thickeners containing a CO2-phile that promotes dissolution and a CO2-phobe that induces viscosity-enhancing intermolecular associations. The initial research was directed at identifying the most CO2-philic hydrocarbon-based polymer. Subsequently, associating groups would be incorporated.;Small sugar acetates are known to be extremely CO2-soluble, but polymeric cellulose triacetate is CO2-insoluble due to its crystallinity. Therefore a high molecular weight, low melting point polymer with per-acetylated monosaccharide side chains, poly (1-O-(vinyloxy)ethyl - 2,3,4,6 -- tetra --O -- acetyl -- beta -- D - glucopyranoside), P(AcGIcVE) was synthesized. This polymer is second most CO2-soluble hydrocarbon-based polymer and is slightly less CO 2-soluble than PVAc.;Amorphous poly(lactic acid) has also been shown to be highly CO 2 soluble over a broad range of molecular weight. The pressure required for dissolution greatly exceeds that associated with PVAc or P(AcGIcVE), therefore PLA is the third most soluble polymer in CO2.;Oligo(vinyl acetate) is a particularly effective CO2-phile. Poly(vinyl acetate), PVAc, remains the most CO2-soluble high molecular weight, non-fluorous polymer that has yet been identified.;PVAc was selected as the base polymer for a copolymeric thickener. A pendant phenyl group was selected for viscosity-enhancing intermolecular associations because this mildly CO2- phobic non-polar group was so effectively used for this purpose in a fluorinated CO2 thickener previously designed by our group. Promising results were obtained with poly(vinyl acetate-covinyl benzoate5%). The viscosity of CO2 increased by roughly 40% at a copolymer concentration of 1wt% and by 80% at 2wt%, at shear rates of 6200-5080 s-1 at 298 K. Therefore poly (vinyl acetate-co-vinyl benzoate5%) is the first documented non-fluorous CO2 thickener capable of increasing the CO2 viscosity substantially at dilute concentrations of ∼1wt%. Unfortunately, the pressure required to dissolve this copolymer in CO 2 at 298 K (∼65 MPa) greatly exceeds the MMP (Minimum Miscibility Pressure) of CO2 floods at the same temperature (∼10 MPa). Because we were not able to identify a hydrocarbon-based polymer more CO 2-philic than PVAc, it is doubtful that a non-fluorous, copolymeric thickener capable of dissolving in CO2 at practical CO2 flooding pressure conditions can be identified.;The only other non-fluorous polymer known to be more CO2-soluble than PVAc is polydimethyl siloxane PDMS. Therefore, we evaluated three commercially available PDMS polymer with pendant phenyl groups. Two PDMS-based copolymers, poly(phenyl methyl siloxane)10%-co-(dimethylsiloxane) (Mw = 90,000 and 17000) were commercially available from Gelest. Neither was soluble in CO2 and copolymers with lesser degrees of phenyl methyl siloxane were not available.;An attempt was also made to design small molecules as thickeners. The first CO2 soluble non-fluorous, acetylated hydrogen-binding compound and the first CO2 soluble non-fluorous dendrimer were synthesized. It was postulated that these compounds would dissolve in CO2 and then form linear macromolecules due to the hydrogen bonding between adjacent molecules. Critical features of these small, self-assembling molecules are the presence of strong and directional hydrogen bonding interactions between carbonyl oxygen and hydrogen in a bis-urea moiety, and the presence of multiple (two or four) highly acetylated "arms" on the periphery of the molecule that promote dissolution in CO2. Although the first non-fluorous, CO 2-soluble hydrogen bonding compound (two arms) and hydrogen-bonding dendrimer (four arms) were designed, neither thickened CO2. The hydrogen bonding compound with two arms did form brittle, microfibrillar, free-standing foams upon the removal of the CO2.
机译：超临界二氧化碳（scCO2）是用于各种化学过程的环保溶剂。在许多情况下，由于大多数极性和离子材料在致密CO2中的溶解度低，scCO2无法替代有机溶剂。已经成功设计了高度可溶于CO 2的氟化聚合物，但是它们昂贵且对环境持久。该项目旨在开发一种可溶解于CO2中并增稠CO2的无氟化合物，从而改善CO2驱油的性能，从而提高采收率。试图生产出含有可促进溶解的CO2-phile和CO2-phobe的CO2增稠剂。引起粘度增强的分子间缔合。最初的研究旨在确定最富二氧化碳的烃基聚合物。随后，将结合缔合基团；已知小糖乙酸酯是极易溶于CO2的，但聚合的三乙酸纤维素由于其结晶性而不溶于CO2。因此，是一种具有过乙酰化单糖侧链的高分子量，低​​熔点聚合物，聚（1-O-（乙烯基氧基）乙基-2,3,4,6-四--O-乙酰基-β-合成了D-吡喃葡萄糖苷，P（AcGIcVE）。该聚合物是第二种最易溶于CO2的烃类聚合物，并且与PVAc相比，CO 2的溶解度稍低。无定形聚乳酸也显示出在很宽的分子量范围内高度可溶于CO 2。溶解所需的压力大大超过了与PVAc或P（AcGIcVE）相关的压力，因此PLA是CO2中溶解度第三高的聚合物。;低聚（醋酸乙烯酯）是一种特别有效的CO2-phile。聚乙酸乙烯酯（PVAc）仍是迄今尚未发现的最易溶于二氧化碳的高分子量非氟聚合物。; PVAc被选作共聚物增稠剂的基础聚合物。选择一个侧基苯基来增强分子间的粘度，因为这种轻度的CO2疏水性非极性基团已被有效地用于我们小组先前设计的氟化CO2增稠剂中。用聚（乙酸乙烯酯-苯甲酸乙烯基乙烯酯）获得令人鼓舞的结果。共聚物浓度为1wt％时，CO2的粘度大约增加40％，而当共聚物浓度为2wt％时，CO2的粘度在298 K下的剪切速率为6200-5080 s-1时增加80％。是第一个有记录的无氟CO2增稠剂，能够在大约1wt％的稀释浓度下基本增加CO2的粘度。不幸的是，在298 K（〜65 MPa）下将该共聚物溶于CO 2所需的压力大大超过了在相同温度（〜10 MPa）下CO2驱替的MMP（最小混溶压力）。由于我们无法鉴定出比PVAc更亲近CO 2的烃基聚合物，因此能否鉴定出能够在实际CO2驱替压力条件下溶于CO2的无氟共聚增稠剂值得怀疑。已知比PVAc更易溶于CO2的非氟聚合物是聚二甲基硅氧烷PDMS。因此，我们评估了三种带有苯基侧基的市售PDMS聚合物。两种基于PDMS的共聚物，聚（苯基甲基硅氧烷）10％-共-（二甲基硅氧烷）（Mw ＝ 90,000和17000）可从Gelest商购获得。两者均不溶于CO2，因此无法获得苯甲基硅氧烷含量较低的共聚物。;还尝试设计小分子作为增稠剂。合成了第一可溶于CO2的非氟，乙酰化的氢结合化合物和第一可溶于CO2的非氟的树状聚合物。据推测，这些化合物会溶解在二氧化碳中，然后由于相邻分子之间的氢键而形成线性大分子。这些小的自组装分子的关键特征是双脲部分中羰基氧和氢之间存在强力的定向氢键相互作用，并且外围存在多个（两个或四个）高度乙酰化的“臂”促进溶解在二氧化碳中的分子的数量。尽管设计了第一个无氟，CO 2可溶的氢键化合物（两个臂）和氢键树状大分子（四个臂），但都没有使CO2增稠。具有两个臂的氢键键合化合物在除去CO2时确实形成了脆的，微原纤维的自立式泡沫。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号