1-Butyl-3-methylimidazolium chloride

cream-colored to yellow mass

To a 50ml Schleck tube was added 1-methyl-1H-imidazole (4.1g, 0.05 mol), 1-chlorobutane (9.2g, 0.1 mol, 2 equiv) and distilled toluene (20 ml), the mixture were heated and stirred at 90 °C oil bath for overnight, after reaction, all the versitile were removed under vacuo. the residue were washed with 2-methoxy-2-methylpropane (3* 20 ml), dried under vacuo, which afforded 3-butyl-1-methyl-1H-imidazol-3-ium chloride (NHC precursor E) as white solid (92percent, 8g)1) N-Methylimidazole (4 g, 48.7 mmol)In a single-necked flask, And then weighed1-Chloromethane6.68 g (72.2 mmol)(The molar ratio of 1-methyl chloride to N-methyl imidazole was about 1.48: 1). After the dropwise addition, the reaction was carried out at 40 ° C for 24 hours. The reaction was monitored by thin layer chromatography , The excess of 1-methyl chloride distillation, the white solid is chlorinated 1-butyl-3-methyl imidazole, the yield of 90percent;In a MW vial, 4 mL of 1-methylimidazole(0.0484 mol) and 7.6 mL of 1-chlorobutane (0.0726 mol) were consecutively added; then, the mixturewas irradiated (200 W) at 150 °C for 25 min. Then, the supernatant 1-chlorobutane was removedand the mixture was then washed with hexane and diluted with CH2Cl2 to be transferred in a roundbottom flask for the removal of solvent under vacuum. The desired product 5 was obtained in 90percentyield. 1H-NMR (200 MHz, CDCl3, ppm): δ = 9.71 (s, 1H), 7.99 (m, 1H), 7.89 (m, 1H), 4.24 (t, 2H, J = 7.0 Hz), 3.91 (s, 3H), 1.77 (m, 2H), 1.30 (m, 2H), 0.88 (t, 3H, J = 7.2 Hz).Synthesis of 1-butyl-3-methylimidazolium chloride: A mixture of 1-methylimidazole (70.0 g, 0.853 mol), ethanenitrile (50 mL) and 1-chlorobutane (102 g, 1.10 mol) are heated under reflux with vigorous stirring for 48 hrs. 1-chlorobutane (99.5percent) is sourced from a commercial supplier (Sigma-Aldrich). Volatile substances are removed in a first step under reduced pressure (ca. 50° C., 20 mbar), and finally, in vacuo (ca. 80° C., 0.01 mbar) during 16 hrs, yielding 1-butyl-3-methylimidazolium chloride ([CAn amount of 1-methylimidazole (10 mmol, 1.745 g) and n-butylchloride (11 mmol, 1.018 g) were sequentially added into a 25 mL round-bottom flask assembled with the condenser. The reaction mixture was stirred magnetically with 250 rpm speed at 60–65 °C for 24 h. After cooling down to room temperature, the reaction mixture was washed with diethyl ether(5 x 10 mL) until no trace of n-butyl chloride, as well as 1-methylimidazole in a solution of diethylether were detected by thin layer chromatography (TLC) and gas chromatography (GC). The othersolution containing recyclable [Bmim]Cl was evaporated under reduced pressure at 80 °C for 30 minto afford a light yellow liquid in high yield (88percent). The identity and purity of [Bmim]Cl obtainedwere analyzed by 1H-NMR, 13C-NMR and LC/MS spectroscopy. In continuation of the preparationof [Bmim]Cl*2AlCl3, an amount of aluminum chloride (4 mmol, 0.534 g) was added slowly into a10 mL round-bottom flask containing [Bmim]Cl (2 mmol, 0.349 g). After that, the reaction mixturewere stirred magnetically at room temperature for 12 h. The identity and purity of acidic catalyst, [Bmim]Cl*2AlCl3, were checked by 1H-NMR and integrated as follows: 1H-NMR (500 MHz, D2O): δ (ppm) 8.65 (s, 1H), 7.43 (s, 1H), 7.38 (s, 1H), 4.14 (t, J = 7.0 Hz, 2H), 3.84 (s, 3H), 1.77–1.82 (m, 2H), 1.23–1.30 (m, 2H), 0.87 (t, J = 7.5 Hz, 3H).To a vigorously stirred solution of 1-methylimidazole (1.25 mol) in toluene (125 mL) at 0 °C, 1-chlorobutane (1.38 mol) was added. 1-Butyl-3-methylimidazolium chloride was prepared from the reaction of N-methylimidazole with n-butylchloride at 80 °C under neat conditions.1-butyl-3-methylimidazolium chloride [bmim][Cl] synthesized accordingto organic synthesis [39]. A mixture of 1-methylimidazole(1 eq) and 1-chlorobutane (1.3 eq) in dry acetonitrile was stirred at75 °C for 48 h under nitrogen.The mixture was cooled to room temperature.The volatile material was removed under reduced pressure andthe remaining light-yellow oil dissolved in appropriate acetonitrileand added dropwise to a flask containing dry ethyl acetate dry ethyl acetatecontaining flask to give [bmim][Cl] as a white crystal in approximately82percent yeild.Two chloride-based ionic liquids, [BMIM]Cl and [AMIM]Cl, were synthesized according to the literature methods [10, 11], respectively. Reactions were carried out under nitrogen atmosphere and followed by ESI-MS and General procedure: C4mimBr was synthesized according to the reported literatures.1 In a 100 mL round-bottom flask, 1-methylimidazole (8.21 g, 0.1 mol) was mixed with n-butyl bromide (16.44 g, 0.12 mol) and allowed to reflux for 24 h at 70 °C. The excess n-butyl bromide was distilled off under reduced pressure and the residue was finally extracted thoroughly 2-3 times (50 mL each) with diethyl ether to remove the traces of unreacted starting materials. A white solid of 1-n-butyl-3-methylimidazolium bromide was obtained in 87percent yield.Equipped with a blender, Reflux condenser and a thermometer 500mL three-necked flask was added 68.60g N-methyl imidazole and 85.65g chlorobutane, And were added 80mL cyclohexane and toluene as the reaction medium, Control the temperature inside the bottle is 70 , After stirring for 48h, the upper solvent and the unreacted raw materials were removed by pouring, The lower oily liquid was hot with ethyl acetate 4 times (each time the amount of 20mL)Remove the liquid transfer to a single mouth flask, Rotate under reduced pressure (water bath temperature was controlled at 70 ) to remove part of the solvent and raw materials unreacted raw materials.Turn the steam transfer to the vacuum drying oven, The temperature is 70 , Vacuum dried 36h, That is to obtain the intermediate l-butyl-3-methylimidazolium chloride [Bmim] Cl, Yield 68.6percent.500 mL equipped with a stirrer, reflux condenser and thermometerThree-necked flask was added 68.60gN-methylimidazole and85.65g chlorobutane, and were added 80mL cyclohexane and toluene as the reaction medium, Control the temperature inside the bottle is 80 , After stirring for 36h, the upper solvent and the unreacted raw materials were removed by pouring, The lower oily liquid was hot with ethyl acetate 4 times (each time the amount of 20mL)Remove the liquid transfer to a single mouth flask, Rotate under reduced pressure (water bath temperature was controlled at 70 ) to remove part of the solvent and raw materials unreacted raw materials. Turn the steam transfer to a vacuum oven, the temperature is 70 , Drying in vacuo for 36 h gave the intermediate productL-butyl-3-methylimidazolium chloride[Bmim] Cl, yield 70.2percent.In the presence of a stirrer, Reflux condenser and a thermometer was charged 68.60 g of N-methylimidazole in a 500 mL three-necked flaskAnd 85.65 g of chlorobutane, And adding 80mL of cyclohexane and toluene as reaction intermediates, The temperature in the control bottle is 70 ° C, After stirring for 48 h, the upper layer solvent and the unreacted starting material were removed by the pouring method, The lower oily liquid was washed 4 times with ethyl acetate (20 mL each)Remove the liquid from the lower layer to the vial, Vacuum distillation (water bath temperature control at 70 ° C) to remove part of the solvent and raw materials in the unreacted raw materials.Steaming finished transferred to a vacuum oven, The temperature is 70 ° C, vacuum drying 36h, To give the intermediate 1-butyl-3-methylimidazolium chloride[Bmim] C1, yield 68.2percent.9.27g (0.1mol) 1-chlorobutane was added dropwise to 11.50g (0.14mol) 1-methylimidazole. The mixture was heated at 65Comparative examples C1 to C3198 g (1 mol) of BMIM OAc (1-butyl-3-methylimidazolium acetate) are placed in a round-bottom flask which has been made inert and is provided with a dropping funnel and reflux condenser. The amount of acid indicated in the appended table is added slowly while stirring, with the temperature being kept below 50° C. (an exothermic reaction is observed during the addition; the temperature is kept down either by appropriately slow addition with air cooling or by cooling with water).After cooling to room temperature, the major part of the volatile constituents is taken off at a pressure of 0.1 mbar, with the internal temperature being increased to 120° C. When no more low boilers are given off from the mixture under these conditions, the mixture is cooled and nitrogen is admitted. The residue is transferred to the reservoir of the short-path distillation and fed in at a rate of 100 ml/h at the evaporator temperature indicated below. The pressure in the short-path distillation is set to 0.05 mbar. The product is obtained as bottom output, so that the short-path distillation here functions as a very efficient form of low boiler stripping.The condensed low boilers comprise water (when an aqueous reagent is added) and acetic acid. BMIM Evaporator Product OAc:acid temp. (salt having Yield No. Acid mol:mol ° C. the new anion) percent Purity* C1 HCl; 35percent in water 1:1.033 170 BMIM Cl 93.5 comprises 20 mol percent of HOAc after first passage comprises 3 mol percent of HOAc after second passage C2 CF3COOH 1:1.017 150 BMIM TFA 90.9 comprises 13 mol percent of HOAc after first passage (trifluoroacetic acid) comprises 4 mol percent of HOAc after second passage C3 CH3SO3H 1:1.005 170/190 BMIM 92.3 comprises 9 mol percent of HOAc after first passage (methanesulfonic CH3SO3 no HOAc after the second passage acid) *Analysis by H-NMRGeneral procedure: 1-butyl-imidazole and acid source were mixed at 0 °C, after removing the water under reduced pressure by using phosphorus pentoxide, after the addition of trimethyl ortho formate is reacted at a given temperature for a predetermined time to remove the triisopropyl ortho formate remaining in the reduced pressure the ionic liquid 13 to 22 respectively was produced.The yield of the ionic liquid 13 to 22 prepared each ion of the acid source, the reaction temperature and reaction time used in the production and accordingly liquids is shown in Table 1.

This salt (bmim) Cl- and AlCl3 can be used in Friedel-Crafts alkylation

Molecular Weight:174.67
Hydrogen Bond Acceptor Count:1
Rotatable Bond Count:3
Exact Mass:174.0923762
Monoisotopic Mass:174.0923762
Topological Polar Surface Area:8.8
Heavy Atom Count:11
Complexity:93.3
Covalently-Bonded Unit Count:2
Compound Is Canonicalized:Yes