Study On Synthesis Of NPS-2 Petroleum Sulfonates

In this paper, the synthetic process is studied in a single tube falling-film sulfonation reactor with SO3 as sulfonation agent and with extract oil A and extract oil B as material oils. The basic properties of the marerials are studied. Pretreatment of meterial oils and the separation of insoluble substance in products are improved. The influence factors of the sulfonation process are investigated to determine the optimum conditions. By the orthogonal test, the optimum conditions are obtained. Via rings method and sprining drop method, surface tension and oil-water interfacial tension are measured. The active components and average molecular weights of products under the optimum conditions are obtained via the two-phase titration method. The CMC of products in the optimum are measured by surface tension method. The molecular structure of optimum products is characterized by using infrared spectrum, NMR and ultimate analysis.It is found that the aromatic contents of meterail oils are more than 60% and the molecular weights are between 340 and 400. They are suitable as raw materials for synthesizing petroleum sulfonates. The optimum conditions of process which uses extract oil A as raw material are: dilution ratio 1.3, acid to hydrocarbon ratio 1.8, gas concentration 4.5%, reaction temperature 40℃, aging temperature 40℃, and aging time 30min. The optimum conditions in process which uses extract oil B as raw material are: dilution ratio 1.6, acid to hydrocarbon ratio 2.0, gas concentration 4.5%, reaction temperature 35℃, aging temperature 40℃and aging time 30min.Product analysis shows that: The effective component of petroleum sulfonate A under optimum conditions is 77.28%. The average molecular weight is 489. The CMC is 0.1%, and the surface tension is 29.85 mN·m-1. Petroleum sulfonate A can make oil-water interfacial tension drop to below 10-3 mN·m-1 in 40 min without any assistants(the concentration is 0.125%). The actives of petroleum sulfonate B is 73.19%. The average molecular weight is 542. The CMC is 0.17%, and surface tension is 32.02 mN·m-1. They are all fit for being EOR petroleum sulfonate. The surfacial tension of petroleum sulfonate A is better than B.Instrument analysis shows that in the infrared spectrum, there are significant infrared absorption peaks in 1190cm-1 and 1060cm-1, confirming the presence of sulfonic acid group. Characterization results of the molecular structure suggest: On average, the molecular of petroleum sulfonate A contains 3 aromatic rings and side chains that contain 2 to 3 branched chains. There are 1.23 sulfonic acid groups, which confirms the product contains monosulfonate mainly. Petroleum sulfonate B contains 4 aromatic rings and side chains that contain 2 to 3 branched-chains. There are 1.40 sulfonic acid groups, which confirms the product contains some disulfonate.