Study On Synthesis And Acid Catalytic Performance In Organic Reactions Of Novel Functional Ionic Liquids

Worldwide demand for environmentally friendly chemical processes and products requires the development of novel and cost-effective approaches to pollution prevention. Green chemistry is a highly effective approach to pollution prevention because it applies innovative scientific solutions to real-world environmental situations. It is best defined as the utilization of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture, and applications of chemical products. Recent years, ionic liquid as an environmentally benign media has been used in many organic synthesis and chemical procedures because of their favorable properties such as negligible vapor pressure, high thermal stability, recyclability and tunable acidity. More recently, some functional acidic ionic liquids have been used in some organic reactions. These acidic ionic liquids based upon poor nucleophilic anions have received increasing attention because they are immiscible with a number of organic solvent and have been proved to be effective catalysts for a variety of reaction. Their acidity can significant improve the reaction conversion and they can easily be recycled in the reaction. In some homogeneous reaction, the reaction system can be separated into two phase due to using these ionic liquids and it is good to separate the products.In this research, kinds and application of ionic liquid were developed. This dissertation mainly falls into several parts: the literature review, synthsis the functional ionic liquids and application in some chemical reaction.In the review section, we mainly introduced the development, buildup, synthesis and application of ionic liquids, especially the functional ionic liquids.The synthsisi and application of functional ionic liquid include following parts.1) In this article, several Br(?)nsted acidic ionic liquids [HMIM]BF₄,[(CH₂)₄SO₃HMIM] [HSO₄],[(Ac)₂BIM]Br and [NMP][HSO₄] were synthesized andused to synthesize the 2,4-diisopropyl-5,5 -dimethyl-1,3 -dioxane through acetalizationof TMPD and isobutyraldehyde. Results show that these functional acidic ionic liquids can avoid the separation issue of products and reactants. Most of them can catalyze the reaction with high catalytic activity, short reaction time, high conversion (≥90 %). As one of the most effective acidic ionic liquids, [(Ac)₂BIM]Br was selected to investigate further effects of different reaction condintions and possibility of reusability. As it shown, ionic liquid still stable enough and has less impact on the catalytic activity after eight reusability.2) Br(?)nsted acidic ionic liquids [BMIM][HSO₄] and [BMM][H₂PO₄] were synthesized. We proceeded the Prins reaction, used to prepare dioxanes, has been limited by complex catalyst separation used six Br(?)nsted acidic ionic liquids as environmentally benign catalysts under mild reaction conditions for the first time. This process is highly effective, environmentally benign, and very selective. Furthermore, [BMIM][HSO₄] ionic liquid was conveniently separated with the products and easily recycled to catalyze Prins reaction again with excellent yields. The use of novel acidic ionic liquids in this reaction provides a better and practical alternative to the existing procedures and provides great promise toward further useful applications. This process will pave a way for large scale applications of Prins reaction.3) Br(?)nsted acidic ionic liquids [TMBSA][HSO₄],[TEBSA][HSO₄],[MORBSA][HSO₄] and [MORPSA][HSO₄] were synthesized. [TMBSA][HSO₄] and [MORBSA][HSO₄] ionic liquids catalyzed efficiently acetylation of acetic anhydride with various alcohols, hydroxyesters and phenols under solvent-free condition. Results showed that [TMBSA][HSO₄] and [MORBSA][HSO₄] ionic liquids able to promote quantitative acetylation at low temperature, in high conversion and selectivity (≥95 %). This process is highly effective, environmentally benign, very selective and easily recycled with excellent conversion and selectivity.4) Methoxyl propylamine acetate functional ionic liquid was synthesized and used as an environmentally benign catalyst for Henry and Knoevenagel condensation reactions under solvent-free condition for the first time. This ionic liquid was shown to effectively catalyze Henry reactions and Knoevenagel reaction of active nitromethane compounds with various aldehydes. Yields from the catalyzed reactions were over 90 %under solvent-free condition. Furthermore, methoxyl propylamine acetate ionic liquid was conveniently separated with the products and easily recycled to catalyze Knoevenagel reaction again with excellent yields.In a word, ionic liquids play an important role in significantly enhancing the reactivity as well as reducing formation of byproducts. It provides better conversion and shorter reaction time than other methods previously reported. The significant advantages offered by this method are fast reaction and high conversion of product. The obvious advantage is recyclability of the catalyst. The use of these new novel ionic liquids in this reaction can be considered as an interesting new alternation. It provides a better and practical alternative to the existing procedures and great promise toward further useful applications.