Preparation Of Acidic Functional Ionic Liquids And Their Catalytic Property For Rosin And Turpentine Reactions

The hydration (preparing terpineol) and the direct esterifcation (preparing bornyl acetate and terpinyl acetate) ofα-pinene, the esterification of terpineol and rosin (preparing terpinyl acetate and methyl abietate respectively), and the polymerization ofα-pinene and rosin (preparing terpene resin and polymerized rosin) are important processes in the chemical industry of forest products. These reactions are concerned with larger molecule reactants using strong acids as catalysts. Usually the traditional Br?nsted acid (H2SO4 and H3PO4) and Lewis acid (AlCl3) are used as catalysts in the reactions, and the drawbacks of these processes include serious corrosion of equipment, complicated separation procedures, environmental problems, and non-recyclable of catalysts. Therefore, more and more attentions have been paid to using novel catalysts for these reactions in recent years.Utilized the multiformity and tunability of ionic liquids (ILs), acidic functional ILs with specialized functions can be prepared by adjusting the combination of cations and anions or linking proper functional group with their cations or anions. As task-specific or tailor-making green catalysts or solvents, acidic functional ILs get more and more attention of researchers, and many catalytic reactions are reported with high conversion and excellent selectivity over them.Base on the structural designability and acidic tunability of IL, Br?nsted, Lewis, Br?nsted-Lewis, and polyether acidic functional ILs ( No articals were reported the synthesis of Br?nsted-Lewis and polyether acidic functional ILs) were synthesized and characterized using FT-IR, NMR, and ESI-MS. The results indicated that the obtained compounds were just the target products with the relevant acidity. The acidity of Br?nsted acidic functional ILs comes from the alkyl sulfonic acid which is covalently tethered in ILs cations, and not easily lost. The acidity of Leiws acidic functional ILs can be adjusted in a wide range depending on the proportion of organic base to Lewis acid, and it is raised by increasing amount of Lewis acids. Br?nsted-Lewis acidic functional ILs are both Br?nsted and Lewis acidic. The cations contribute to the Br?nsted acidity, and the anions determine the Lewis acidity. Acidic functional polyether ILs not only have the Br?nsted acidity, but also have the functional group of polyoxyethylene which has the property of emulsification.The synthesized functional ILs were used in the reactions of hydration, esterifcation and polymerization ofα-pinene, esterification of terpineol and rosin, and polymerization of rosin to investigate their activation and reusability. Some catalysts that are of best catalytic activities to these reactions were found, and the optimum conditions were obtained. Compared with the traditional catalysts, the catalytic performances of filtrated ILs were better. Among all the investigated ILs, 1-(3-sulfonic acid)propyl-3-methylimidazole dihydrogen phosphate ([HSO3-(CH2)3-mim][H2PO4]) was of better catalytic performance for the hydration ofα-pinene and esterification of terpineol,the conversions of reagents were 97.1 % and 100 %, and the selectivitis of target products were 47.1 % and 87.2 % respectively. 3-(Sulfonic acid)propyl- triethylamine dihydrogen phosphate ([HSO3-(CH2)3-NEt3][H2PO4]) was of better catalytic performance for the esterification ofα-pinene to prepare terpinyl acetate, and 83.7 % conversion ofα-pinene and 36.5 % selectivity of product were obtained. (3-Sulfonic acid)-propyltriethylamine hydrosulfate ([HSO3-(CH2)3-NEt3][HSO4]) had better catalytic performance for the esterification ofα-pinene to synthesize bornyl acetate,the conversion and selectivity were 96.9 % and 45.1 %. 1-(3-Sulfonic acid)propyl-3-methylimidazole p-toluene- sulfonate ([HSO3-(CH2)3-mim]pTSA) was of better catalytic activation to the esterification of rosin, and the product with 16.7 mg/g acid value was obtained. For the Lewis acidic functional ILs, 1-ethoxycarbonylmethyl-3-methylimidazole chloroaluminate ([EtOCOCH2-mim]Cl- A1C13) had better catalytic performance for the polymerization ofα-pinene, the yields of liquid resin and solid resin were 40 % and 52 % respectively, and the softening point of solid resin reached 115℃. For the Br?nsted-Lewis acidic functional ILs, (3-sulfonic acid)propyltriethylammonium chlorozincinate ([HSO3-(CH2)3-NEt3]Cl-ZnCl2) had compara- tive catalytic activation with that of H2SO4, and the softening point of product was 134℃. In the acidic functional polyether ILs, 1-(3-sulfonic acid)propyl-3-polyoxyethyleneimidazole dihydrogen phosphate ([HSO3-(CH2)3-im-(C2H4O)?H][H2PO4], ?=15) was beter catalytic performance for the hydration ofα-pinene and the esterification of terpineol,the conversion of reagents were 89.4 % and 100 %, and the selectivitis of products were 50.0 % and 87.8 % respectively. It was also found that acidic functional ILs rendered the reactions of rosin andα-pinene simple experimental and product isolation procedure.Moreover,the usage of acidic functional ILs in the reactions of rosin andα-pinene gets rid of the drawbacks of traditional catalysts, and realizes the integrative process of reaction, seperation, and reusage of catalysts. This study expands the application of ILs in the field of the forest products, and can provide guidance for ILs to be used in these reactions.