本文選題：縮醛化反應(yīng)　切入點(diǎn)：聚甲氧基二烷基醚　出處：《催化學(xué)報(bào)》2017年05期

【摘要】：聚甲氧基二烷基醚(RO(CH_2O)_nR)具有高的十六烷值(CN)和含氧量,能顯著改善柴油的燃燒特性,有效提高熱效率,大幅減少碳煙和NO_x排放,被認(rèn)為是一種優(yōu)良的環(huán)保型燃油組分.隨著 R基碳鏈的增長(zhǎng),CN值、熱值和閃點(diǎn)逐漸增大,密度和冷凝點(diǎn)逐漸降低.同時(shí),該類化合物具有優(yōu)異的溶解及滲透性能,能與許多有機(jī)溶劑互溶,低毒,可以用作溶劑或顏料分散劑.近年來(lái),聚甲氧基二甲基醚(CH_3O(CH_2O)_nCH3,PODEn,DMM_n)的制備及應(yīng)用研究受到廣泛關(guān)注,而對(duì)封端基團(tuán)( R)碳數(shù)大于1的多醚類化合物的研究鮮有文獻(xiàn)報(bào)道.本文以Brφsted酸性離子液體為催化劑,對(duì)甲醛和二乙氧基甲烷或脂肪醇(碳數(shù)≥2)縮醛化反應(yīng)制備聚甲氧基二烷基醚的反應(yīng)性能進(jìn)行了研究,考察了離子液體結(jié)構(gòu)和酸性對(duì)其催化性能的影響.結(jié)果表明, SO_3H功能化的離子液體[MIMBs]HSO_4在催化三聚甲醛與二乙氧基甲烷的縮醛化反應(yīng)中表現(xiàn)出最好的催化活性.考察了催化劑用量、原料配比、反應(yīng)溫度、反應(yīng)壓力和反應(yīng)時(shí)間等因素對(duì)反應(yīng)性能的影響,并得到了最佳反應(yīng)條件,在n([MIMBs]HSO_4):n(DEM1):n(HCHO)=1:80:80,140°C下反應(yīng)4 h,甲醛轉(zhuǎn)化率達(dá)到了92.6%,DEM_(2 8)選擇性為95.1%.考察了不同甲醛源(三聚甲醛和多聚甲醛)與提供封端基團(tuán)化合物(二乙氧基甲烷、乙醇、丙醇和丁醇)的縮醛化反應(yīng).結(jié)果發(fā)現(xiàn),在反應(yīng)過(guò)程中不生成水或不引入水的條件下,具有更高的反應(yīng)轉(zhuǎn)化率和產(chǎn)物選擇性.分別采用靜置分層和萃取實(shí)現(xiàn)了催化劑的分離與重復(fù)使用.推測(cè)反應(yīng)機(jī)理認(rèn)為,三聚甲醛首先在氫鍵作用下分解生成甲醛單體,甲醛和二乙氧基甲烷通過(guò)碳正離子反應(yīng)機(jī)理實(shí)現(xiàn)了DEM_n的鏈增長(zhǎng).
[Abstract]:Poly (methoxydialkyl ether) has high cetane number (CNN) and oxygen content. It can significantly improve the combustion characteristics of diesel fuel, increase thermal efficiency and reduce soot and NO_x emissions significantly. It is considered to be an excellent component of environment-friendly fuel.The calorific value and flash point gradually increase, and the density and condensation point decrease gradually with the increase of CN value of the R-base carbon chain.At the same time, this kind of compound has excellent solubility and permeability, and can be used as solvent or pigment dispersant because of its low toxicity and mutual solubility with many organic solvents.In recent years, the preparation and application of Poly (methoxydimethyl ether) tippon Ch _ 3O _ (O) / Ch _ s _ 2O _ (n) _ (Ch _ 3H _ (3)) POD _ End _ (DMMN) have received extensive attention, but there are few reports on the studies of poly (ethers) whose capping group carbon number is more than 1.In this paper, using Br 蠁 sted acidic ionic liquid as catalyst, the reaction performance of acetalization of formaldehyde with diethoxymethane or fatty alcohol (carbon number 鈮，

本文編號(hào)：1726695