Preparation method of carbamide-free disulfonic acid triazinyl fluorescent whitening agent liquid

The invention discloses a preparation method of carbamide-free disulfonic acid triazinyl fluorescent whitening agent liquid. In current various preparation methods of the fluorescent whitening agent liquid, the most common preparation method of fluorescent whitening agent liquid comprises the following steps of: acquiring solid substance via acid precipitation, and subsequently, adding alkali and carbamide to form liquid, wherein a large amount of waste liquid is generated by acid precipitation and is unfavorable for the cleaner production. The preparation method of carbamide-free disulfonic acid triazinyl fluorescent whitening agent liquid comprises the following steps of: by taking a condensation product of DSD acid and cyanuric chloride as a skeleton, adding monomers of aniline and organic amine, by taking tertiary amine as an acid and alkali neutralizer in a condensation reaction of a third step to form an ammonium salt system, and then acquiring directly-liquefied product via a nano filtering and desalti