Synthesis Of High-polymeric β-Naphthalenesulfonic Acid-formaldehyde Condensate

Concrete water-reducing admixtures have become an indispensable part as the 5^th composition in nowadays concrete industry, Among all kinds of superplasticizers for cement,Sodium salts of sulfonated naphthalene-formaldehyde condensates are widely used in commercial concrete in china at prcsent.Using technical naphthalene,sulfuric acid and formaldehyde as raw materials,the synthesis of this kind of surfactant with high polymerization degree (18-23) is studied by sulfonation,decomposition,water condensation and other steps.The synthetic process of producing high-polymericβ-naphthalenesulfonic acid-formaldehyde condensate is introduced in this paper. Results of the test establish the feasible technical conditions. Also,the results of applied experiments are reviewed in concrete engineering.Different matching proportion of naphthalene with formaldehyde,various reaction temperture and so on were tested to show the effect on the nucleosome number of condensate. The tests on flow,subsidence and water-reduce are completed Experiment research on the synthesis of naphthalene high range water reducing agent.This paper discusses synthesis of high polymerization degree napthalenesulfonic acid and formaldehyde condensate.Especially in the process of sulfonation and condensation systematic research esare carried out and the traditional" concentrated sulphuric acid" sulfonation is improved.The factors influencing productivity and polymerization degree are investigated.High polymerization degree naphthalenesulfonic acid and formaldehyde condesate is prepared delevatingth eacidity.A cleaner process is proposed to separate Na₂SO₄ from naphthalene series based water reducing agent by using alcohol as salting up promoterThe mass concentration of Na2SO4 in the powder product can decrease to less than 1.4%.Its structure and water reducing mechanism were studied by Infrared spectrum method and other methods, industrial-scale production of this surfactan are reviewed.The results show that high-polymericβ-naphthalenesulfonic acid-formaldehyde condensate is superior than low-polymeric or medium-polymericβ-naphthalenesulfonic acid-formaldehyde condensate on flow,subsidence and water-reduce performance.