Salicylaldehyde CAS 90-02-8

A kind of synthetic method of o-hydroxybenzaldehyde, used raw material is chloroform, phenol, sodium hydroxide, and this method is formed through reflux, acidification, extraction, distillation, acidolysis, evaporation; 1000 milliliters mass concentration is 40-50 Add 150-250 grams of phenol into the reactor with a condensing reflux device, stir continuously, and heat it in a water bath to 55-65 °C, add 300-350 grams of chloroform, and raise the temperature to to 70-80°C, and keep warm and reflux for 1-3 hours; acidification is to adjust the pH value of the reactant to 2-3 with sulfuric acid with a mass concentration of 10-20% of the reaction material; distillation is to add the material to ethyl acetate, Stir continuously for 15-25 minutes, heat to 60-65°C, the evaporated gas is recovered by condensation, when no condensate is formed, raise the temperature to 75-80°C, the evaporated gas is recovered by condensation, when there is no condensation When the liquid is formed, raise the temperature to 175-185°C, the evaporated gas is recovered by condensation, stop heating, and separate the oil; acidolysis is to mix the oil with an equal volume of saturated sodium bisulfite solution, stir evenly, and statically Set aside for 35-40 minutes, filter, mix the precipitate with sulfuric acid with a mass concentration of 10-20%, stir for 1-3 hours, let stand, and separate the oil layer; the evaporation temperature is 190-200°C.

Get 2.0×10-3g tetra-(o-chlorophenyl) cobalt porphyrin, 3.5×10-5 g chloride tetra-(p-nitrophenyl) iron porphyrin, 3.8×10-5 g cobalt sulfate, Add 3.8×10‑5g ferrous nitrate, 5.4g o-cresol and 3.0g sodium hydroxide into a 100mL autoclave, add 20mL methanol, feed oxygen at a pressure of 0.4MPa, and react in a water bath at 65°C for 8 hours . After the reaction was completed, the reaction solution was detected by high performance liquid chromatography, and the conversion rate of o-cresol was 54.0%, the selectivity of o-hydroxybenzaldehyde was 25.1%, and the yield of o-hydroxybenzaldehyde was 13.5%.

Put 275.5 kg (2.5 moles) of o-cresol, 210 kg (1.3 moles) of phosphorus oxychloride and 0.25 kg of magnesium oxide into a 500L reactor equipped with a stirring anchor, condenser and cyclone separator. Raise the temperature of the material to 80°C within more than 1 hour, raise the temperature at 100°C to 130°C within 4 hours, then raise the temperature to 170°C within 2.5 hours, and then keep it warm for 2 hours to obtain a specific gravity of D2041.25 and a total chlorine content of 10 % of esterification products.

Put the esterified product into a -500L reaction kettle equipped with a stirring blade, a chlorine pipe and a cyclone separator. Raise the temperature of the system to above 150°C and start passing chlorine. The speed of passing chlorine is 36 kg/hour. Keep the pressure of the kettle at about 960mmH2O, and keep the temperature in the range of 190°C to 200°C. After about 15 to 16 hours, when the specific gravity of the reaction material reaches 1.51 and the total chlorine content reaches 39%, the chlorination reaction is completed.

Put the chlorination product, 1630 kg of water and 2.7 kg of NNO diffusion agent into the jacketed hydrolysis reaction kettle equipped with stirring anchor, condenser and aldehyde water separator. After the water mixture was condensed and stratified, the water flowed back into the kettle. After about 8 hours, the hydrolysis reaction was complete, and 198.25 kg of o-hydroxybenzaldehyde with a content of more than 95% was obtained.