Method for synthesizing slump-resistant naphthalene-based efficient water reducing agent

The invention belongs to the technical field of building materials and particularly discloses a method for synthesizing a slump-resistant naphthalene-based efficient water reducing agent. The method comprises the steps of adding industrial naphthalene or refined naphthalene into a glass-lined reactor, heating to melt, adding 98% industrial concentrated sulfuric acid, carrying out sulfonation reaction for 2-3 hours at the temperature of 135-175 DEG C, cooling to the temperature of 116-138 DEG C, adding water, carrying out hydrolysis reaction for 0.5-2.5 hours, cooling to the temperature of 90-110 DEG C, adding an industrial formaldehyde solution, carrying out condensation reaction for 3-8 hours, cooling to the temperature of 68-95 DEG C, adding alkylamine or alkyloamide, reacting with a naphthalene sulfonic formaldehyde condensate for 0.5-2.5 hours at the reaction temperature of 55-90 DEG C, adding sodium hydroxide, neutralizing until the pH value is 6-7, filtering a liquid product so as to remove impurities, concentrating the liquid product and carrying out spray drying, thereby obtaining a powdered product. The product prepared by the method disclosed by the invention is applicable to the preparation of concrete admixtures and is also applicable to the preparation of dispersants and oilfield chemicals.