| Safe, clean and efficient production is the goal of current chemical industry development, it is aimed to achieve zero discharge in production, which is the theme of "green growth" in the world. Reaction-separation coupled process is the focus of current chemical production and separation, and one of the important means to improve the efficiency of reaction and separation process, reduce the process energy consumption, ease the process of industrial resources, energy and environment bottleneck problems. The core solutions are the design of the reactor, the integration process and new catalysts preparation. The use of new catalysts is one of the keys to realize coupling and integrating the reaction and separation, especially there are many problems in processing the process of green and efficient energy, low comprehensive cost etc with the use of widely applied traditional inorganic/organic acid, solid catalysts, etc in industry. Ionic liquid are a kind of green, stable and efficient catalysts and organic solvents, which have been widely used in the reactions such as esterification, alkylation, oxidation and reduction and so on. However, further improvement of ionic liquids in catalytic and application performance were still needed for production in industry. Therefore, in this paper the design and construction of BrOnsted acidic ionic liquids for realizing the coupled and intensified reaction and separation were the focus, and the performance of BrOnsted acidic ionic liquids in esterification and ethylbenzene nitration were also investigated.First, in the esterification of short carbon chain and small space steric hindrance, twobi-component ionic liquid catalysts were formulated for the use of catalysts in the esterification of acetic acid and n-butanol. It is interpreted that [BSEt3N][HSO4] of strong acidity and low concentration plays a major role in catalytic activity of BBAILs and noncorrosive [Hpy][HSO4] and [Hmpy][HSO4] of weak acidity and high concentration bears its responsibility in co-catalysts and solvents. It is investigated that the bi-component ionic liquid catalysts have both advantages of catalytic acidity and low corrosion compared with pure Br(?)nsted acidic ionic liquids, and the reaction system could formulated liquid-liquid biphase in few seconds (less than 5 min), butyl acetate was in the light phase, by-product water and catalysts were in the heavy phase, the unreacted reactants were in a certain proportion participated in the two phases. After the reaction, the unreacted and few reactants could be extracted by butyl acetate to the light phase, the ionic liquids and water formed the heavy phase. In here, the coupling of reaction and separation is realizing, and it contains reaction, separation and extraction, the term 'reactive extraction' is used to name such an intensified process. And this unique process could break reaction equilibrium that make the reaction to the right to achieve a high conversion of acetic acid (more than 95%) and intensify the reaction. In addition, a liquid-liquid biphase catalytic reaction dynamic model based on bi-component ionic liquid catalysts was also studied, and the liquid distribution coefficients of each components in the two phases were first used in this model. It is investigated that this model could well fitting the liquid-liquid biphase catalytic results, which enrich the Aspen database for simulating the production of butyl acetate. Otherwise, we propose a kind of coupling and intensifying reaction and separation technical process with the use of bi-component Br(?)nsted acidic ionic liquids as catalysts.Second, a kind of hydrogen bonding Br(?)nsted acidic ionic liquids of strong acidity and highly symmetrical structure were designed and synthesized, and used for catalyzing the esterification of long chain fatty acids with large space steric hindrance. The catalysts were obtained by reaction in 1:2 molar ratio of binary heterocyclic (1,10'-phenanthroline,2,2'-pyridine and 4,4'-pyridine) with double N atoms and sulfuric acid. Different from traditional BrOnstedionic liquids, they all have a N H hydrogen bond and a N-H covalent bond, and the ability of proton transport, which could influence the acidity of catalysts. These special properties enable the catalysts have the advantages of inorganic acid (sulfuric acid) of strong acidity and ionic liquids of unique solubility to separate from the reaction system, which could realize the coupling of reaction and separation. It is investigated that the catalysts have both advantages of organic acid (sulfuric acid) of strong acidity existence of N H hydrogen bond could due to the existence of N H hydrogen bond, and ionic liquids of unique solubility to separate from the reaction system. In the esterification of isopropyl myristate, the conversion of myristic acid could reach 90.% in the presence of 4% mol [Phen-H]HSO4(H2SO4)catalyst at 95? in 480 min in 1:3 molar ratio of acid and alcohol. In this reaction, hydrogen bonded BrOnsted acidic ionic liquids could partly dissolved in the system that could decrease the mass transfer resistance limit bringing from solid catalysts. At the end of the reaction, liquid-liquid biphase were formed, and the the mixture of isopropyl myristate, myristic acid and isopropanol were in the light phase, catalysts and water were in the heavy phase. After removing the water, the catalyst could directly reused for some times without any obvious decrease of catalytic acidity and mass loss. It is illustrated that the hydrogen bonded Br(?)nsted acidic ionic liquids were a kind of efficacious catalysts in the esterification of long chain fatty acids.Then, it is important for flavour esters of unsaturated bonds to use recyclable catalysts of high catalytic activity and selectivity in production. We synthesized a kind of hydrogen bonded BrOnsted acidic ionic liquids by simple neutralization reaction between 1,10-phenanthorine and acids (methane sulfonic acid, sulfuric acid and p-toluenesulfonic acid). The structural characterization and theoretical calculation were used to explain the unique structure of these catalysts with both N-H hydrogen bond and N-H covalent bond, and the acetylation of geraniol and acetic anhydride with the used of these catalysts was also studied. It is investigated-that the catalysts have both the advantages of strong acids (high catalytic acidity) and weak acids (high selectivity), in the presence of 2% mol [Phen-H]CH3SO3(CH3SO3H) as catalyst at 50? in 120 min, the conversion of geraniol could reach 99.% and the selectivity of geranyl acetate was 96.9%. Because of the generation of acetic acid from acetic anhydride, the phase separation formulated by traditional ionic liquids (pridine, imidazoles or quaternary ammonium ionic liquids, etc) was difficult to be observed. While, hydrogen bonded BrOnsted acidic ionic liquids used in this reaction could dissolved in the system without mass transfer resistance that intensify the reaction at the beginning, and precipitated from the system to form liquid-liquid biphase that was not happened with homogeneous catalysts instead. Furthermore, these hydrogen bonded Br(?)nsted acidic ionic liquids are "reaction-induced self-separation catalysts" and can be reused with convenient method. The advantages of hydrogen bonded BrOnsted acidic ionic liquids in catalytic activity, selectivity, separation, and price are very attractive in the practical application of these o-acetylation reactions in industry.Finally, we prepared a kind of tertiary amine based BrOnsted acidic ionic liquids composed of HSO4- to replace part sulfuric acid for the ethylbenzene nitration which was catalyzed by mixed inorganic acids. It is illustrated that mixed acids with tertiary amine based Br(?)nsted acidic ionic liquids could effectively improve the para-selectivity, the p/o ((para and meta)/ortho)value rose from 1.10 to 1.34, the optimized reaction temperature could low to 35?, and liquid-liquid biphase was observed, the up phase was mainly composed of nitroethylbenzene and ethylbenzene, the down phase was the mixture of mixed acids and ionic liquids.The focus of this paper were based on the strong acidity, high selectivity and unique dissolution of Br(?)nsted acidic ionic liquids to design and prepare different ionic liquids for different reaction system that realize the coupling and intensification of reaction and separation. In addition, the structure of hydrogen bonded Br(?)nsted acidic ionic liquids is beneficial for the selection of efficacious catalysts in following work. |
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