In contrast to a recently expressed, and widely cited, view that “Ionic liquids are starting to leave academic labs and find their way into a wide variety of industrial applications”, we demonstrate in this critical review that there have been parallel and collaborative exchanges between academic research and industrial developments since the materials were first reported in 1914 (148 references)

Applications of ionic liquids in the chemical industry

Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition.

Acidic Ionic Liquids.

Recent advances in ionic liquid catalysis

Ionic liquids (ILs), salts with melting points below 100 °C, represent a fascinating class of liquid materials typically characterized by an extremely low vapor pressure. Besides their application as new solvents or as electrolytes for electrochemical purposes, there are two important concepts of using ILs in catalysis: Liquid–liquid biphasic catalysis and IL thin film catalysis. Liquid–liquid biphasic catalysis enables either a very efficient manner to apply catalytic ILs, e.g. in Friedel–Crafts reactions, or to apply ionic transition metal catalyst solutions. In both cases, phase separation after reaction allows an easy separation of reaction products and catalyst re-use. One problem of liquid–liquid biphasic catalysis is mass transfer limitation. If the chemical reaction is much faster than the liquid–liquid mass transfer the latter limits the overall reaction rate. This problem is overcome in IL thin film catalysis where diffusion pathways and thus the characteristic time of diffusion are short. Here, Supported Ionic Liquid Phase (SILP) and Solid Catalyst with Ionic Liquid Layer (SCILL) are the two most important concepts. In both, a high surface area solid substrate is covered with a thin IL film, which contains either a homogeneously dissolved transition metal complex for SILP, or which modifies catalytically active surface sites at the support for SCILL. In each concept, interface phenomena play a very important role: These may concern the interface of an IL phase with an organic phase in the case of liquid–liquid biphasic catalysis. For IL thin film catalysis, the interfaces of the IL with the gas phase and with catalytic nanoparticles and/or support materials are of critical importance. It has recently been demonstrated that these interfaces and also the bulk of ILs can be investigated in great detail using surface science studies, which greatly contributed to the fundamental understanding of the catalytic properties of ILs and supported IL materials. Exemplary results concerning the IL/vacuum or IL/gas interface, the solubility and surface enrichment of dissolved metal complexes, the IL/support interface and the in situ monitoring of chemical reactions in ILs are presented. Important concepts in catalysis with ionic liquids are reviewed, including Supported Ionic Liquid Phase (SILP) and Solid Catalyst with Ionic Liquid Layer (SCILL), along with the detailed analysis of the relevant interfaces using surface science methods.

/pdf/ionic-liquids-in-catalysis-5085ji31q7.pdf

Ionic Liquids in Catalysis

Hydrodesulfurization (HDS), a widely employed method in industries for the desulfurization of fuel oils, such as gasoline and diesel fuel is faced with the challenge of producing lower-sulfur or sulfur-free fuel oils, which are required by more and more countries. However, HDS is not very effective for the removal of thiophenic sulfur compounds due to sterically-hindered adsorption on the catalyst surface, unless operated under harsh conditions, such as high temperature, high pressure, and requirement of a noble catalyst and hydrogen. Extractive desulfurization (EDS) of fuel oils using ionic liquids (ILs) has been intensively studied in recent decades and has a good future as an alternative or complementary method to HDS. In this review, we reviewed the research results of EDS using ILs and provided comprehensive discussions on diverse factors, which influence desulfurization, such as the IL species, IL–oil mass ratio, initial sulfur content, temperature, time, mutual solubility, multiple extractions and regeneration. Potential problems or shortcomings were also stated. Some other desulfurization methods currently under study, such as extraction, oxidation, adsorption and biodesulfurization were also briefly outlined. It can be inferred that ILs remain a class of ideal solvents to realize clean fuel oil in the near future because of their desirable physiochemical properties, which are lacking in molecular organic solvents, while there are possible challenges, such as relatively high viscosity and low efficiency.

A review of extractive desulfurization of fuel oils using ionic liquids

The present invention pertains to a method for manufacturing alkylate oil using a composite ionic liquid as catalyst. A mixture of isobutane and C4 olefins is used as the raw material, and a composite ionic liquid is used as catalyst to carry out an alkylation reaction. The alkane/olefin ratio in the raw material is higher than 1:1. In the composition of the aforementioned composite ionic liquid catalyst, the cations come from a hydrohalide of an alkyl-containing amine or pyridine, while the anions are composite coordinate anions coming from two or more metal compounds. One of the metal compounds is an aluminum compound, while other metal compounds are compounds of Group IB and Group IIB elements of the Periodic Table and the transition metals. The present invention also provides a design of static mixer reaction apparatus that can realize the aforementioned manufacturing method. The method of the present invention increases the selectivity of the alkylation reaction to give the alkylation product a relatively high octane number and further increase the product yield. Also, the manufacturing operation is simplified, and the cost can be reduced. This method is an environmentally friendly method that will not pollute the environment.

Method for manufacturing alkylate oil with composite ionic liquid used as catalyst

Alkylation of isobutane and butene was carried out in a continuous unit using triethylamine hydrochloride–aluminium(III)chloride ionic liquid as catalyst. The effects of additives of HCl and metal chlorides on the properties of ionic liquids for alkylation were investigated. Improvement of production distribution with high yields of C8 and selectivity of TMP under a mild reaction condition has been observed after addition of CuCl.

Effects of additives on the properties of chloroaluminate ionic liquids catalyst for alkylation of isobutane and butene

The present invention discloses method of using composite ionic liquid as catalyst to prepare alkylated oil preparation. In the alkylation process, isobutane and C4 olefine in the ratio of 1-200 as material are made to reaction at the temperature from -20 deg.c to 100 deg.c and pressure 0.1-1.6 MPa inside a conventional high pressure reactor in the presence of composite ionic catalyst with cation from alkyl containing hydrohalide of amine or pyridine and composite anion prepared with two or more metal compounds. The present invention has raised selectivity of alkylation, high octane number of product, high yield, simple operation, low cost and no environmental pollution.

Preparing method for alkylate agent using compound ion as catalyst

In the alkylated oil preparing process, room temperature acid ionic liquid is used as catalyst and isobutane and olefin are used as material. The catalyst is prepared through reaction between alkylamine hydrohalide or pyridine hydrohalide and metal halide. The alkylation reaction is performed at -20 to +80 deg.c and 0.1-1.6 MPa, and the material isobutane/olefin ratio is 1-200. The alkylated oil yield may reach 160-180 vol% of olefin, and its C8 component may reach 60-80%. The catalyst has no descent in yield of alkylated oil and C8 selectivity after being used for 10 times and has excellent regeneration performance. The present inventino can inhibit olefin condensation, cyclization and other side reactions; and the ionic liquid has no corrosion and no volatility and is easy to separate from alkylated oil.

Method of utilizing ionic liquid as catalyst in preparing alkylated oil

Mixture of isobutane and 4C alkene is alkylated using ion-cluster liquid catalyst, and alkylate is manufactured. Ion-cluster liquid catalyst contains cation consisting of hydrogen halide of amine having alkyl group or hydrogen halide of pyridine, and anion made up of anion of coordination complex obtained from two or more types of specific metallic compounds. Mixture (15) of isobutane (7) and 4C alkene is alkylated using an ion-cluster liquid as a catalyst, and alkylate is manufactured. The ion-cluster liquid catalyst contains a cation consisting of hydrogen halide of amine having alkyl group or hydrogen halide of pyridine, and an anion made up of anion of coordination complex obtained from two or more types of metallic compounds. One type of metallic compound is an aluminum metallic compound (C1) and another metallic compound (C2) is a compound of IB group, IIB group and transition metal elements of periodic table. The ratio of alkane and alkene in the mixture is greater than 1 to 1. An independent claim is included for static mixing-vessel reactor having sedimentation device (4) for carrying out sedimentation, and fractional-distillation apparatus for returning upper fractional distillation to a raw material mixing vessel.

Manufacture of alkylate for petrochemical industry, involves alkylating mixture having preset amount of isobutene and specific alkene using ion-cluster liquid catalyst containing specific anion and cation

Huang Chongpin

Papers

Method for manufacturing alkylate oil with composite ionic liquid used as catalyst

Effects of additives on the properties of chloroaluminate ionic liquids catalyst for alkylation of isobutane and butene

Preparing method for alkylate agent using compound ion as catalyst

Method of utilizing ionic liquid as catalyst in preparing alkylated oil

Manufacture of alkylate for petrochemical industry, involves alkylating mixture having preset amount of isobutene and specific alkene using ion-cluster liquid catalyst containing specific anion and cation