Institute of Chemistry, University of São Paulo, P.O.B. 26077, 05513-970 São Paulo, Brazil.
Carbohydr Polym. 2014 Jan 30;101:444-50. doi: 10.1016/j.carbpol.2013.09.043. Epub 2013 Sep 21.
A novel electrolyte, dibenzyldimethylammonium fluoride has been obtained essentially anhydrous (BMAF-0.1H2O) by a simple route. Its thermal stability, relative to tetra(1-butyl)ammonium fluoride trihydrate (TBAF3H2O) has been demonstrated by thermogravimetric analysis. DMSO solution of (BMAF-0.1H2O) dissolves microcrystalline- and fibrous celluloses; the dissolved biopolymers have been acylated by ethanoic-, butanoic-, and hexanoic anhydride. The degrees of substitution of the esters are higher than with TBAF3H2O/DMSO. The reasons are discussed in terms of differences in electrolyte structure and contents of water of hydration, whose presence leads to side reactions and decreases of the basicity of (F(-)). This conclusion is corroborated by molecular dynamics simulations of the interactions of glucose dodecamer/R4NF-hydrate/DMSO. These show that the interactions oligomer-F(-)-water is operative only for TBAF3H2O/DMSO. The efficiency of BMAF-0.1H2O/DMSO is explained based on better accessibility of the biopolymer due to efficient hydrogen-bonding between its hydroxyl groups and the essentially desolvated (F(-)).
一种新型电解质二苄基二甲基氟化铵通过简单的路线得到了实质上无水的形式（BMAF-0.1H2O）。通过热重分析证明了其热稳定性相对于四（1-丁基）氟化铵三水合物（TBAF3H2O）有所提高。（BMAF-0.1H2O）在 DMSO 溶液中可溶解微晶和纤维状纤维素；溶解的生物聚合物已被乙酸酐、丁酸酐和己酸酐酰化。酯的取代度高于 TBAF3H2O/DMSO。这一结论是基于电解质结构和水合程度的差异来讨论的，水的存在会导致副反应和降低（F（-））的碱性。葡萄糖十二聚体/R4NF-水/DMSO 相互作用的分子动力学模拟证实了这一点。这些模拟表明，只有在 TBAF3H2O/DMSO 中，寡聚物-F（-）-水的相互作用才起作用。BMAF-0.1H2O/DMSO 的效率可以通过其羟基与实质上去溶剂化的（F（-））之间有效的氢键作用来解释，这使得生物聚合物更容易接近。
