An environmentally friendly preparation method for Solvent Orange 107 dye includes the following steps:
(1) Vacuum-pump 350 kg of 3,3-dimethyl-2-methyleneindoline (precisely measured manually) is introduced into the reaction vessel, stirring is started, and 300 kg of dimethyl sulfate is added through a metering tank in a thin stream. The reaction is carried out at 25°C and atmospheric pressure for 6 hours (the reaction endpoint can be detected using existing technology after the reaction is completed); then 650 kg of 30% liquid alkali (30 wt% sodium hydroxide solution) and 1000 kg of fresh water are added through a metering tank. After the addition is completed, the mixture is stirred for half an hour, allowed to stand and separate into layers. The water layer is separated and discharged into a sewage treatment plant, and the oil layer is heated to 120°C for dehydration. After dehydration is completed, the oil layer is cooled and then placed in a barrel to obtain the intermediate.
(2) Vacuum-pump 350 kg of manually measured intermediate (excess portion goes to the next batch), 400 kg of xylene, 350 kg of 1,3,5-pyrazolone, and 220 kg of trimethyl orthoformate are manually drawn into the reactor. The mixture is heated to 80°C and reacted at atmospheric pressure for 12 hours. Then the temperature is lowered to 40°C and transported through a closed pipeline to a closed filtration tank. Vacuum filtration is performed, the mother liquor is dried, and 600 kg of methanol is added for washing. The filter cake is first washed several times with 1000 kg of fresh water. The mother liquor and washing liquid are collected, and methanol is recovered by distillation. The mixture of xylene and water is then distilled out, allowed to stand and separate into layers. The xylene is reused, and the water layer goes to the wastewater treatment plant. The filter cake is then pumped into hot water in batches for washing and filtration until neutral (generally, it needs to be washed more than ten times, with a total water consumption of about 10,000 kg). The reaction and filtration equipment are sealed, and the balance pipe leads to the tail gas collection system. The washing wastewater goes to the wastewater treatment plant. The material obtained from filtration was manually transferred to a dryer and dried with hot air generated by steam heating to obtain the finished product (reaction conversion rate 96.4%, yield 97.9%).
