CN102816182B - A kind of dication ionic liquid of Han Phosphonium and Synthesis and applications thereof - Google Patents

Abstract

The invention discloses a phosphonium-containing dication ionic liquid and its preparation and application. The dianionic ionic liquid of the present invention has the general structural formula shown in Figure (I), wherein: n is an integer of 2 to 8; R ₁ , R ₂ and R ₃ are saturated or unsaturated hydrocarbon groups containing 1 to 20 carbon atoms , aryl or heterocyclic group; cation A is selected from imidazoles, quaternary ammoniums, quaternary phosphoniums, pyridines, pyrroles, thiazoles, triazol imidazoles, pyrrolines, thiazolines, amino acids, guanidine One of classes and benzotriazole imidazoles; X ^- and Y ^- are organic or inorganic anions. The phosphonium-containing dianion ionic liquid of the present invention can be used to catalyze the cycloaddition of carbon dioxide and epoxy compounds to synthesize cyclic carbonates, and has the advantages of high activity, good selectivity, good stability, no need for solvents and cocatalysts, and the like.

Description

A kind of phosphonium-containing dicationic ionic liquid and its preparation and application

technical field

The invention relates to a dication ionic liquid, in particular to a dication ionic liquid containing phosphonium ions, a preparation method and application thereof.

technical background

Ionic liquids refer to salts composed of organic cations and inorganic/organic anions that are liquid at or near room temperature. In recent years, due to the advantages of low melting point, low volatility, good thermal stability, high electrical conductivity, wide electrochemical window, adjustable structure and physical and chemical properties, ionic liquids have been widely used in organic synthesis, electrochemical research, extraction and separation, and materials It has been widely used in the fields of synthesis and catalysis.

The widely studied ionic liquids are mainly monocationic ionic liquids [Green Chem, 2002, 4, 407-413], such as imidazolium salts, pyridinium salts, quaternary ammonium salts, and quaternary phosphonium salts. However, in recent years, due to the advantages of better thermal stability, higher density, wider liquid range and better physical and chemical controllability, dicationic ionic liquids have attracted the attention of researchers, and have been widely used in some fields. application. Jin Chuanming and others invented a class of fluorine-containing bis-imidazole cationic ionic liquids that can be used as lubricants [Patent No. 201010557991.5]. Armstrong research combined a series of symmetrical bis-imidazolium cationic ionic liquids [J Am Chem Soc, 2005, 127, 593-604], which can be used as solvents for high-temperature organic synthesis reactions [Org Lett., 2005, 7(19), 4205-4208], and gas chromatography stationary phase [Anal Chem, 2005, 77(19), 6453-6462]; Armstrong’s research group also synthesized a series of asymmetric cation ions by using imidazolium salt, pyrrole salt and quaternary ammonium salt Liquid, and its physical and chemical properties were studied [Chem Mater., 2007, 19(24), 5848-5850]. Leclercq et al. also synthesized several bis-imidazolium cationic ionic liquids and used them as solvents for organic reactions [Green Chem, 2007, 9, 1097-1103]. Lall et al. synthesized a series of polyammonium and diammonium cationic ionic liquids [Chem Commun, 2000, (12), 2413-2414]. The Shreeve research group synthesized dianionic pyridinium salt ionic liquids using bipyridyl [Inorg Chem, 2003, 42, 7416-7424; Chem Commun., 2003, (12), 1366-1367]. Compared with monocationic ionic liquids, there are relatively few research reports on the synthesis and application of dicationic ionic liquids, especially the phosphonium-containing dianionic ionic liquids have not been reported yet.

Carbon dioxide is currently the most important greenhouse gas on the earth, but it is also a non-toxic, cheap and abundant C1 resource. With the intensification of the "carbon source crisis" caused by the shortage of fossil fuels, the resource utilization of carbon dioxide has become one of the hot topics of international research in recent years. The synthesis of cyclic carbonates through the cycloaddition reaction between carbon dioxide and epoxides is one of the few ways to industrially utilize carbon dioxide. Cyclic carbonate is a very important chemical, it can be used as a clean polar solvent, it can be used in the production of phenolic resin, polycarbonate synthesis, thermosetting resin synthesis, it can also be used as an electrolyte for high energy density batteries and capacitors, and cosmetic additives And chemical intermediates, etc. Since the properties of ionic liquids can be adjusted by adjusting the combination of anions and cations or the introduction of functional groups, more and more researchers have used ionic liquids as catalysts for cycloaddition reactions in the past decade. However, the reported ionic liquids used as catalysts for cycloaddition reactions are mostly monocationic ionic liquids, such as imidazoles, quaternary ammonium salts, and quaternary phosphonium salts. Although these ionic liquids have certain catalytic activity to the cycloaddition reaction, they all have one or several problems as follows: their own activity is not high or they show better catalytic activity in the presence of co-catalysts such as metal halides. Poor stability, active components are sensitive to water, harsh reaction conditions, etc. Therefore, it is an urgent problem to develop ionic liquids with better stability and higher catalytic activity by adjusting the types, quantities and functional groups of ionic liquid anions/cations.

Contents of the invention

The object of the present invention is to provide a novel phosphonium-containing dianionic ionic liquid.

Another object of the present invention is to provide a preparation method of the above-mentioned ionic liquid.

The above-mentioned ionic liquid provided by the present invention can be used to catalyze the cycloaddition reaction of carbon dioxide and epoxide to synthesize cyclic carbonate.

The technical scheme that the present invention adopts for achieving the purpose of the invention is as follows:

A phosphonium-containing dicationic ionic liquid is characterized by the following general structural formula:

                                                 

In the formula: n is an integer from 2 to 8.

A is a cation, selected from imidazoles, quaternary ammoniums, quaternary phosphoniums, pyridines, pyrroles, thiazoles, triazimidazoles, pyrrolines, thiazolines, amino acids, guanidines, and benzotriazole imidazoles one of the classes.

Substituents R ₁ , R ₂ , R ₃ are saturated or unsaturated hydrocarbon groups, aromatic groups or heterocyclic groups containing 1-20 carbon atoms, and R ₁ , R ₂ , R ₃ may be the same or different. Among them, R ₁ , R ₂ and R ₃ are preferably alkyl groups and aromatic groups.

Anions X ^– , Y ^– are selected from F ^– , Cl ^– , Br ^– , I ^– , BF ₄ ^– , BF ₆ ^– , ClO ₄ ^– , BH ₄ ^– , SbF ₆ ^– , ZnCl ₃ ^– , SnCl ₃ ^– , CF ₃ SO ₃ ^– , NO ₂ ^– , NO ₃ ^– , SO ₄ ^– , PO ₄ ^– , RCOO ^– , N(FSO ₂ ) ₂ ^– , N(CF ₃ SO ₂ ) ₂ ^– , C(CF ₃ SO ₂ ) ₃ ^– , CF ₃ COO ^– , CF ₃ SO ₃ ^– , CH ₃ SO ₃ ^– , ROSO ₃ ^– , X ^– and Y ^– may be the same or different. Wherein X ^- and Y ^- are halide ions, preferably Cl ^- and Br ^- .

The synthetic method of the phosphonium-containing dianion ionic liquid provided by the invention comprises the following steps:

1) Add the compound R ₁ R ₂ R ₃ P to a dihalogenated hydrocarbon solution containing the same molar amount, and react at 80-120 ^o C for 12-24 hours to obtain a quaternary phosphonium halide containing an alkyl halide group;

2) Combine the quaternary phosphonium salt halide containing haloalkyl groups with the molar ratio of 1:1~1:1.1 with BF ₄ ^– , BF ₆ ^– , ClO ₄ ^– , BH ₄ ^– , SbF ₆ ^– , ZnCl ₃ ^– , SnCl ₃ ^– , CF ₃ SO ₃ ^– , NO ₂ ^– , NO ₃ ^– , PO ₄ ^– , RCOO ^– , N(FSO ₂ ) ₂ ^– , N(CF ₃ SO ₂ ) ₂ ^– , C(CF ₃ SO ₂ ) ₃ ^– , CF ₃ COO ^– , CF ₃ SO ₃ ^– , CH ₃ SO ₃ ^– or ROSO ₃ ^– anion alkali metal salts are dissolved in a solvent and reacted at room temperature for 2 to 6 hours to obtain quaternary phosphonium halides with corresponding anions compound;

3) Dissolve the quaternary phosphonium salt halide obtained in step 1) or step 2) in a solvent, and add imidazoles, organic amines, organic phosphorus, pyridines, pyrroles, thiazoles, One of imidazoles, pyrrolines, thiazolines, amino acids, guanidines, and benzotriazole imidazoles, react at 70~120 ^o C for 12~36 hours to obtain phosphonium-containing dianions ionic liquid;

4) The phosphonium-containing dianionic ionic liquid obtained in step 3) can also be combined with anion-containing BF ₄ ^– , BF ₆ ^– , ClO ₄ ^– , BH ₄ ^– , SbF ₆ ^– , ZnCl ₃ ^– , SnCl ₃ ^– , CF ₃ SO ₃ ^– , NO ₂ ^– , NO ₃ ^– , PO ₄ ^– , RCOO ^– , N(FSO ₂ ) ₂ ^– , N(CF ₃ SO ₂ ) ₂ ^– , C(CF ₃ SO ₂ ) ₃ ^– , CF ₃ COO ^– , CF ₃ SO ₃ ^– , CH ₃ SO ₃ ^– or ROSO ₃ ^– the alkali metal salt of the anion is dissolved in the solvent at a molar ratio of 1:1~1:1.1, and reacted at room temperature for 2~6 hours, A phosphonium-containing dianionic ionic liquid with the corresponding anion is obtained.

In the above synthesis method, the solvent used is one selected from toluene, benzene, chloroform, acetonitrile, ethyl acetate, ethanol, acetone, 1,1,1-trichloroethane or tetrahydrofuran.

The novel phosphonium-containing dianionic ionic liquid provided by the present invention can be used to catalyze carbon dioxide and epoxy compound cycloaddition reaction to synthesize cyclic carbonate, and its general reaction formula is:

When R ₁ =H, R ₂ is one of H, CH ₃ , CH ₂ Cl, C ₂ H ₅ , C ₄ H ₉ , C ₆ H ₅ , C ₄ H ₉ O, and C ₇ H ₇ O.

When R ₁ ≠H, the structure of the epoxy compound is:

 

The application of the phosphonium-containing dianionic ionic liquid involved in the present invention in the preparation of cyclic carbonates is characterized in that carbon dioxide and epoxy compounds are used as reactants, and the catalyst is selected from one of the phosphonium-containing dianionic ionic liquids, the catalyst The dosage is 1‰~2% of the molar weight of the epoxy compound, and the cyclic carbonate is synthesized under the conditions of a reaction pressure of 0.1~10.0 MPa, a temperature of 25~180 ^o C, and a reaction time of 0.5~24 hours.

According to the synthetic method of the cyclic carbonate provided by the present invention, the raw material epoxy compound is selected from propylene oxide, ethylene oxide, epichlorohydrin, styrene oxide, 1,2-epoxycyclohexane, 1, One of 2-epoxybutane, 4-vinyl-1,2-epoxycyclohexane, n-butyl glycidyl ether, and 2,3-epoxypropylphenyl ether.

The phosphonium-containing dianion ionic liquid provided by the invention is a new type of ionic liquid with good hydrothermal stability, easy synthesis and adjustable physical and chemical properties. This type of ionic liquid can efficiently catalyze the cycloaddition of _CO2 and epoxides to synthesize cyclic carbonates, and has the advantages of high activity, good selectivity, good stability, and no need for solvents and co-catalysts.

Detailed ways

In order to further illustrate the details of the present invention, several embodiments are enumerated below, but the present invention is not limited to the following embodiments, and within the scope not departing from the purpose described before and after, changes and implementations are all included in the technical scope of the present invention.

Example 1:

Under nitrogen protection, add 2.620 g of triphenylphosphine and 1.2 mL of 1,4-dibromobutane into a two-necked round-bottomed flask with a magnetic stirrer, then add 30 mL of toluene as a solvent, mix thoroughly, and stir to reflux After reacting for 24 h, filter under reduced pressure and wash with toluene and diethyl ether three times successively, and finally vacuum-dry at 60 ^o C for 12 h to obtain 4-bromobutyltriphenylphosphonium bromide.

The equation for the reaction is as follows:

 

Example 2:

Under the protection of nitrogen, 1.200 g of 4-bromobutyltriphenylphosphonium bromide and 0.700 g of 1-carboxymethylimidazole were added to a two-necked flask, and then 30 mL of toluene was added, stirred and refluxed for 24 h, cooled, pumped filtered, and washed three times with toluene and diethyl ether successively to obtain a white solid, and finally vacuum-dried at 60 ^o C for 12 h to obtain the target dianionic ionic liquid.

The equation for the reaction is as follows:

 

Example 3

Under the protection of nitrogen, 1.200 g of 4-bromobutyltriphenylphosphonium bromide and 1.310 g of triphenylphosphonium were added to a two-necked flask, then 30 mL of toluene was added, stirred and refluxed for 24 h, cooled, and suction filtered. And washed three times with toluene and diethyl ether successively to obtain a white solid, and finally vacuum-dried at 60 ^o C for 12 h to obtain the target dianionic ionic liquid.

The equation for the reaction is as follows:

 

Example 4

Under nitrogen protection, 1.200 g of 4-bromobutyltriphenylphosphonium bromide and 0.7 mL of triethylamine were added to a two-necked flask, then 30 mL of toluene was added, stirred and refluxed for 24 h, cooled, filtered with suction, and After washing with toluene and diethyl ether three times in sequence, a white solid was obtained. After recrystallization with ethyl acetate, it was dried under vacuum at 60 ^o C for 12 h to obtain the target dianionic ionic liquid.

The equation for the reaction is as follows:

 

Example 5

Under the protection of nitrogen, 2.50 mL of tributylphosphine and 1.2 mL of 1,4-dibromobutane were added into a two-necked flask, then 30 mL of toluene was added, stirred and refluxed for 24 h, cooled, suction filtered, and successively used Wash with toluene and diethyl ether three times, and dry under vacuum at 60 ^o C for 12 h to obtain 4-bromobutyltributylphosphonium bromide.

The equation for the reaction is as follows:

 

Example 6

Add 2.09 g of 4-bromobutyltributylphosphonium bromide to 50 mL of an aqueous solution containing 0.92 g of potassium hexafluorophosphate, stir at room temperature for 4 h, filter with suction, wash with distilled water until there is no Br ^– , and store at 60 ^o C under vacuum for 12 h to obtain 4-bromobutyltributylphosphonium hexafluorophosphate.

The equation for the reaction is as follows:

Example 7

Under the protection of nitrogen, 2.420 g of 4-bromobutyltributylphosphonium hexafluorophosphate and 0.41 g of 1-methylimidazole were added to a two-necked flask, and then 30 mL of toluene was added, stirred and refluxed for 24 h, cooled, Suction filtration, followed by washing with toluene and diethyl ether three times to obtain a white solid, and finally vacuum drying at 60 ^o C for 12 h to obtain the target dianionic ionic liquid.

The equation for the reaction is as follows:

 

Example 8

In a 100 mL stainless steel autoclave, add 0.2120 g of the phosphonium-containing dianionic ionic liquid obtained in Example 2 and 2.5 mL of propylene oxide successively, seal it, fill it with 2.5 MPa carbon dioxide, react at 120 ^o C for 4 h, and cool To room temperature, excessive carbon dioxide was discharged, and the product was quantitatively analyzed by gas chromatography, and the selectivity of the product propylene carbonate was 99.2%, and the yield was 98.9%.

Example 9

In a 100mL stainless steel autoclave, after successively adding 0.1050 g of phosphonium-containing dianionic ionic liquid and 2.5mL of propylene oxide obtained in Example 2, seal it, fill it with 2.5 MPa carbon dioxide, react at 130 ^o C for 2.5 h, and cool to At room temperature, excessive carbon dioxide was discharged, and the product was quantitatively analyzed by gas chromatography. The selectivity of the product propylene carbonate was 99.3%, and the yield was 89.7%.

Example 10

With embodiment 8, the phosphonium-containing double cationic ionic liquid catalyst structure used is

, the addition amount is 0.2020 g, and other conditions remain unchanged, the selectivity of the obtained product propylene carbonate is 99.2%, and the yield is 98.6%.

Example 11

In a 100 mL stainless steel autoclave, add 0.1932 g of the dianionic ionic liquid obtained in Example 2 and 2.5 mL of epichlorohydrin successively, seal it, fill it with 2.5 MPa carbon dioxide, react at 120 ^o C for 4 h, and cool to At room temperature, excessive carbon dioxide was discharged, and the product was quantitatively analyzed by gas chromatography. The selectivity of the corresponding cyclic carbonate obtained was 97.3%, and the yield was 96.5%.

Example 12

In a 100 mL stainless steel autoclave, after successively adding 0.1492 g of the dianionic ionic liquid obtained in Example 2 and 2.5 mL of epoxy cyclohexane, seal it, fill it with 2.5 MPa carbon dioxide, react at 120 ^o C for 4 h, and cool to At room temperature, excessive carbon dioxide was discharged, and the product was quantitatively analyzed by gas chromatography. The selectivity of the corresponding cyclic carbonate obtained was 99.1%, and the yield was 83.0%.

Example 13

In a 100 mL stainless steel autoclave, after successively adding 0.2667 g of the dianionic ionic liquid obtained in Example 3 and 2.5 mL of propylene oxide, seal it, fill it with 2.0 MPa carbon dioxide, react at 130 ^° C for 3 h, cool to room temperature, Excessive carbon dioxide was discharged, and the product was quantitatively analyzed by gas chromatography, and the selectivity of the corresponding cyclic carbonate was 99.5%, and the yield was 97.0%.

Example 14

With embodiment 8, the phosphonium-containing double cationic ionic liquid catalyst structure used is

, the addition amount is 0.2450 g, filled with 3.0 MPa carbon dioxide, reacted at 140 ^o C for 4 h, and other conditions remain unchanged, the selectivity of the obtained product propylene carbonate is 99.3%, and the yield is 98.8%.

Example 15

With embodiment 8, its structure of the dicationic ionic liquid catalyst containing phosphonium used is

, the addition amount is 0.2450 g, filled with 2.5 MPa carbon dioxide, reacted at 120 ^o C for 4 h, and other conditions remain unchanged, the selectivity of the obtained product propylene carbonate is 99.2%, and the yield is 98.1%.

Claims (7)

1., containing a dication ionic liquid for Phosphonium, it is characterized in that there is following general structure:

In formula: n is the integer of 2 to 8;

A is positively charged ion, is selected from imidazoles, quaternary phosphine class, quaternary amines a kind of;

Substituent R ₁, R ₂, R ₃for saturated or unsaturated alkyl, aromatic base, heterocyclic group containing 1 ~ 20 carbon atom, R ₁, R ₂, R ₃can be identical, also can be different;

Negatively charged ion X ^-, Y ^-for Cl ^-, Br ^-, I ^-, BF ₄ ^-, BF ₆ ^-, X ^-, Y ^-different.

2. the dication ionic liquid of Han Phosphonium according to claim 1, is characterized in that R ₁, R ₂and R ₃preferably containing alkyl and aromatic group.

3. a preparation method for the dication ionic liquid containing Phosphonium according to claim 1, is characterized in that comprising the steps:

1) by compound R ₁r ₂r ₃p is added to and is dissolved in two halohydrocarbon solutions of certain solvent, 80 ~ 120 ^ounder C condition, reaction obtains haloalkyl containing group quaternary alkylphosphonium salt halogenide for 12 ~ 24 hours;

2) haloalkyl containing obtained group quaternary alkylphosphonium salt halogenide is carried out ion exchange reaction with the salt containing specific negatively charged ion, obtain containing specific negatively charged ion quaternary alkylphosphonium salt accordingly;

3) haloalkyl containing group quaternary alkylphosphonium salt step 1 or 2 obtained is dissolved in certain solvent, adds the one in imidazoles, quaternary phosphine class, quaternary amines, under solvent action, two of mixing kinds of ionic liquids is dissolved, completely 70 ~ 120 ^ounder C condition, reaction obtains the dication ionic liquid of Han Phosphonium for 12 ~ 36 hours;

4) the dication ionic liquid obtained and the salt containing specific negatively charged ion are carried out ion exchange reaction, obtain the dication ionic liquid containing desired anion.

4. the preparation method of the dication ionic liquid of Han Phosphonium according to claim 3, is characterized in that used solvent is selected from toluene, benzene, trichloromethane, acetonitrile, ethyl acetate, ethanol, acetone, 1，1，1-trichloroethane or tetrahydrofuran (THF) a kind of.

5. an application for the dication ionic liquid containing Phosphonium according to claim 1, is characterized in that can be used for catalysis CO ₂with epoxy compounds cycloaddition synthesizing annular carbonate.

6. the application of the dication ionic liquid of Han Phosphonium according to claim 5, it is characterized in that being to use epoxy compounds and carbonic acid gas to be reactant, catalyzer is selected from the one in the dication ionic liquid of Han Phosphonium, catalyst levels is 1 ‰ ~ 2% of epoxy compounds molar weight, be 0.1 ~ 10.0 MPa in reaction pressure, temperature is 25 ~ 180 ^oc, the reaction times is synthesizing annular carbonate under 0.5 ~ 24 hour condition.

7. the application of the dication ionic liquid of Han Phosphonium according to claim 5, it is characterized in that raw material epoxy compounds is selected from propylene oxide, oxyethane, epoxy chloropropane, Styrene oxide 98min., 1,2-epoxy cyclohexane, 1,2-butylene oxide ring, 4-vinyl-1, a kind of in 2-epoxy cyclohexane, n-butyl glycidyl ether, 2,3-epoxypropyl phenylethers.