Isobutylparaben CAS 4247-02-3

Method 1: Add 0.05mol p-hydroxybenzoic acid, 10mL toluene and a certain amount of isobutanol and catalyst into a three-necked flask equipped with a thermometer, a water separator, and a reflux condenser. The water separator is pre-filled with isobutanol, and heated Reflux the reaction and start timing when condensate appears. After reacting for a certain period of time, let stand and cool, the reaction liquid is transferred to a distillation bottle by decantation, and the unreacted isobutanol is separated by distillation under reduced pressure. Pour the distilled residue into distilled water, adjust the pH value to 7-8 with 10% sodium carbonate solution, stir first and then let stand until all solid products are precipitated, filter with suction, wash, and dry at 40°C to constant weight to obtain White powdery product, weigh and calculate the yield. The yield of isobutylparaben is 88.7%.

Method 2: Nano-solid superacid TiO2/SO42-catalyzed synthesis of isobutylparaben

1) Preparation of catalyst

Place the Erlenmeyer flask equipped with magnets on a constant temperature magnetic stirrer, add a certain amount of titanium tetrachloride and a small amount of ethylene glycol as a dispersant in the Erlenmeyer flask, start the magnetic stirrer, and add water to the Erlenmeyer flask until When titanium tetrachloride meets water, the titanium hydroxide produced is completely dissolved. Under the condition of stirring at low temperature, slowly add 12% ammonia water into the titanium tetrachloride solution, adjust the pH value to 9, and continue stirring for 3 hours to obtain Ti(OH)·4nH2O precipitate, age at room temperature for 24 hours, and filter with suction , washed with distilled water until no Cl- is detected, then dried at 110°C, ground, and sieved (100 mesh) to obtain the former yield of amorphous TiO2. A certain concentration of H2SO4 aqueous solution is impregnated, soaked for 1 hour, suction filtered, dried and ground, and roasted in a muffle furnace at 450-500 °C for 2-3 hours to obtain nano-solid superacid catalyst TiO2/SO42 under different conditions. -, put in a desiccator for later use.

2) Synthesis of isobutylparaben In a 100mL three-neck flask equipped with a stirrer, water separator and thermometer, add a certain amount of p-hydroxybenzoic acid, isobutanol, catalyst and water-carrying agent benzene, and heat slowly , timing at the beginning of reflux, stop heating after a certain period of reaction, remove the catalyst by suction filtration, steam distillation to remove excess isobutanol and water-carrying agent benzene (recovery treatment), filter the remaining reaction liquid while it is hot, and pour the filtrate into a container Cool in a beaker with a certain amount of distilled water to obtain light yellow crystals, filter and dry with suction to obtain crude ester. Recrystallize with a certain proportion of ethanol solution to obtain a white solid product. Dry in vacuum, weigh the mass, determine the melting point and calculate the yield.