Studies On Synthesis And Properties Of Various Alkyl Methylnaphthalene Sulfonate Surfactants And Environmentally Benign Catalysts Promoted Long-chain Alkylations Of Methylnaphthalene

At present, the surfactants for domestic oil field lease test mainly depend on import, cost is very high. Many researches mainly focus on some mixed surfactants, petroleum sulphonates and heavy alkyl benzene sulphonates. It's difficult to satisfy the request for stable and high efficient enhanced oil recovery, now that these products are extremely uncertain. Therefore, to explore the low price and high efficient surfactants for enhanced oil recovery, which are prepared from distinguish clearly materials, has important using value and realistic meaning.In this paper, a series of various chain-length alkyl methylnaphthalene surfonate surfactants have been synthesized on the basis of "tailoring technology". The reaction conditions for alkylation of methylnaphthalene with n-bromoalkanes are optimized, and the optimal reaction conditions are: 3:1 for methylnaphthalene to bromoalkane, and 3:1 for cyclohexane to methylnaphthalene in the presence of 2% of anhydrous aluminum chloride at 80 ℃ for 2-4 hours. The series of high purity (more than 98%, obtained by GC) of various length side-chain alkyl methylnaphthalene (AMN) intermediates have been obtained. The synthesized AMN intermediates are sulfonated by using 20% oleum as sulfonating agent. Here the appropriate concentration of hydrochloride lavation method has been adopted to separate the mono- and di- sulfonic acids directly. The optimal hydrochloride concentrations are found to separate various chain-length alkyl methylnaphthalene mono- and di- sulfonic acids, and the satisfactory separation efficiency is obtained. The separated alkyl methylnaphthalene monosulfonic acids are neutralized, eliminated salts by anhydrous ethanol and decolored by activated carbon, the series of high purity (more than 95.6%, by HPLC) of sulfonate (AMNS) surfactants are achieved, and characterized by HPLC, ESI/MS, IR and UV.The surface tensions of a series of AMNS surfactant aqueous solutions are measured with a ring method. It's found that the synthesized surfactants possess high capacity and efficiency of lowering surface tension. The dynamic interfacial tensions (DIT) between crude oil, offered from Shengli and Daqing Oilfields, and series of AMNS surfactants, including hexyl, octyl, decyl, dodecyl, tetradecyl methylnaphthalene sulfonates, flooding systems have been measured. The flooding systems with strong alkaline, buffered alkaline and without alkaline are studied. Effects of chain-length and concentration of AMNS surfactants, alkalinity and salinity on the DIT behaviors are investigated. It's found that, under the seemly conditions, DIT can reach and maintain ultralow at a long time, and even to reach 10-6 mN.m-1 at the optimum conditions. Results show that there exists obvious synergism and antagonism among salt, alkaline and surfactant. For the less lipophilic surfactants, the synergism is dominating, but for stronger lipophilic surfactants, antagonism is leading. The optimal surfactant concentration, alkalinity and salinity for lowering the dynamic interfacial tension to ultralow value are relative. On the basis of these results, the...