2-Nitrobenzyl bromide

white to light yellow crystal powde

In a 5000-L bromination reactor, 300 kg of dichloroethane, 226 kg of o-nitrotoluene, and 27 kg of azobisisobutyronitrile are successively added. After stirring for 20 minutes, the solution is pumped into a high tank for use; and the bromination reactor is put in again. 300 kg of dichloroethane and 226 kg of o-nitrotoluene were mixed well, and 889.03 kg of 40percent hydrobromic acid was added, and the mixture was stirred at a temperature of 72 to 75°C. In the upper slot The mixed solution and 448.26 kg of 30percent hydrogen peroxide were slowly added dropwise to the bromination reactor at an acceleration of 1:4. At the end of the addition, the reaction was continued for 2 hours. After the reaction was completed, the temperature was lowered to room temperature, and the reaction liquid was subjected to HPLC analysis. The conversion of the raw material was greater than 99.0percent, and no by-product such as dibrominated product was generated. The molar ratio of raw material, 40percent hydrobromic acid and 30percent hydrogen peroxide in the reaction is 1: 1.2:1.2. The solution was allowed to stand for delamination and the upper aqueous layer was separated; after the lower organic phase was washed with 600 L of water, the solvent was distilled off under reduced pressure and rinsed with cold dichloroethane to obtain white o-nitrobenzyl bromide solid product. It is 98.5percent.1) The o-nitrotoluene with a mass percentage of 99.15percent is mixed with azobisisobutyronitrile, and then dissolved at 7 g/The mass flow of min is passed through the first module through the metering pump, and the azobisisobutyronitrile is 0.03 of the mass of o-nitrotoluene;2) Aqueous hydrogen peroxide solution with a mass percentage of 5percent is passed through the metering pump at a mass flow rate of 24 g/min.Mixing with o-nitrotoluene and azobisisobutyronitrile in a module, the molar ratio of o-nitrotoluene to hydrogen peroxide is1.00:0.7, the first module controls the reaction temperature to be 60 ° C;3) pumping the mixed liquid treated in step 1) and step 2) into the second module, synchronizing the mass percentage to5percent hydrobromic acid is fed into the second module through a metering pump at a mass flow rate of 50 g/min, mixed and reacted, and the second module is controlled.The reaction temperature is 150 ° C, the molar ratio of o-nitrotoluene and hydrobromic acid is 1.00:0.6;4) The mixture liquid obtained in the step 3) is continuously passed through 6 reaction modules in series, and the temperature of the reaction module is 150.°C;5) The liquid after the step 4) is taken out and diluted with cold water to control the temperature of the reaction system to 10 ° C, and the reaction is quenched.Receiving time 20min;6) The reaction liquid of step 5) was kept at 10 ° C for 2 h, filtered and dried to obtain 208.9 g of o-nitrobenzyl bromide. The yield was95.2percent, purity is 99.1percent.With stirring, thermometer, Add 127.5 g of o-nitrotoluene to the 1 L reaction flask of the condenser.300 g of 1, 2-dichloroethane, 140.2 g of 1, 3-dibromo-5, 5-dimethylhydantoin and 6.6 g of AIBN, Slowly warm to 83 ° C, Control the heating rate, Preventing violent backflow and causing the material to be washed, Reflux for 3-4h until the solution is colorless.Sampling control, After passing the test, Stop the reaction, Cool down to 20 degrees, filter, The filtrate was decomposed to 60 degrees under reduced pressure.Obtain bromide.Normalized to: 91.8percent o-nitrobenzyl bromide, 5.3percent o-nitrotoluene, 2.1percent o-nitrobenzylidene dibromide.The yield of o-nitrobenzyl bromide was 91.1percent.O-nitrotoluene (3.4g, 25mmol) is dissolved in 140ml of anhydrous carbon tetrachloride, and benzoyl peroxide (0.290g, 1.2mmol) and N-bromosuccinimide (4.450g, 25mmol) are added. The reaction mixture is stirred, heated at reflux for 4 hours until N-bromosuccinimide is floated up completely. Cooling and then filtrating, washing with cold sodium bicarbonate aqueous solution (2x), and then ice-water (2x), and drying over anhydrous magnesium sulfate overnight. After filtration and concentration, the product is recrystallized with aqueous ethanol to obtain o-nitrobenzyl bromide as a white crystal, with a yield of 84.5percent, m.p. 45-47°C.O-nitrotoluene (3.4 g, 25 mmol) is dissolved in 140 ml of anhydrous carbon tetrachloride, and benzoyl peroxide (0.290 g, 1.2 mmol) and N-bromosuccinimide (4.450 g, 25 mmol) are added. The reaction mixture is stirred, heated at reflux for 4 hours until N-bromosuccinimide is floated up completely. Cooling and then filtrating, washing with cold sodium bicarbonate aqueous solution (2.x.), and then ice-water (2.x.), and drying over anhydrous magnesium sulfate overnight. After filtration and concentration, the product is recrystallized with aqueous ethanol to obtain o-nitrobenzyl bromide as a white crystal, with a yield of 84.5percent, m.p. 45-47° C.To a four-necked flask irradiated with a 300 W-LED lamp, 34.2 g of o-nitrotoluene, 33.8 g of hydrobromic acid having a mass concentration of 48percent, and 100 g of chlorobenzene were sequentially added.Heating to 60 ° C, Slowly add 25.5g of hydrogen peroxide with a mass concentration of 30percent using a peristaltic pump.The reaction temperature was controlled at 60 ° C ± 2 ° C.After 3 hours, the drop is completed.At this point the system is orange. Continue the insulation reaction for 2h, The o-nitrotoluene is no longer converted, the heating is stopped, and the organic phase is separated.The reaction conversion rate was 82.7percent, and the yield of o-nitrobenzyl bromide was 74percent2-nitrotoluene (5.0 g, 36.50 mmol) was dissolved in 100 mL of carbon tetrachloride and N-bromosuccinimide(6.5 g, 36.50 mmo 1), Adding a catalytic amount of a photoinitiator dibenzoyl peroxide, Heating up to 100 ° C, Reflux for 48 h. The reaction solution was returned to room temperature, The solvent was removed by distillation under reduced pressure, 50 mL of ice water was added, Extracted with ethyl acetate (40 mL X3)The extract was washed with saturated brine, Dried over anhydrous sodium sulfate and concentrated to a crude product.The crude product was purified by silica gel column chromatography (petroleum ether) to give 2-nitrobenzyl bromide (3.5 g, 44.81percent).A mixture of l-methyl-2-nitrobenzene (20 g, 144.53 mmol), NBS (28.4 g, 158.85 mmol), and AIBN (0.2 g) in CClGeneral procedure: To a solution of Ph3P(OAc)2, was added 3-phenylpropanol (1 mmol, 0.137 mL). The progress of the reaction was monitored by TLC (Table 3, entry 2). After completion of the reaction (0.3 h) the reaction mixture was filtered to remove the precipitated NH4Br followed by evaporation of the solvent. Column chromatography of the crude mixture on silica gel using n-hexane/EtOAc (3:1) as the eluent gave 3-phenylpropyl acetate in 90percent yield (0.159 g).

Molecular Weight:216.03
XLogP3:2.7
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:1
Exact Mass:214.95819
Monoisotopic Mass:214.95819
Topological Polar Surface Area:45.8
Heavy Atom Count:11
Complexity:146
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes