Synthesis And Application Of Water-Soluble C₉ Petroleum Resin With Scale-Inhibiting Preformance

Water soluble C9 petroleum resin was prepared by radical solution copolymerization with C9 fraction, a by-product from the production of ethylene, and monomers such as maleic anhydride ( MA ) and acylic acid ( AA ). The synthesized copolymers exhibited good scale-inhibiting performance.The cracking crude C9 fraction from Yanshan Petrochemical Company was rectificated and analysed by GC-MS. The analytical result indicated that the main components to be copolymerized availably in the C9 fraction were dicyclopentadiene (DCPD).The copolymerization of DCPD/MA and DCPD/AA initiated with benzoyl peroxide (BPO) was investigated respectively. Potentiometric titration was applied to determine the compositions of the copolymer.The results are: r1 (MA) =0.0265, r2 (DCPD) =0.6776, r1(DCPD)=0.0184, r2(AA)=2.5906, at 70℃; r1 (MA) =0.0419, r2 (DCPD) =0.4891 at 80℃; r1 (MA) =0.0397, r2 (DCPD) = 0.7296 at 90℃; It revealed that the result of potentiometric titration was agreed with that of 13C-NMR spectrum with -0.77% of the deviation. The mole ratio of norbomene ring to cyclopentene ring of DCPD in poly(DCPD-co-MA) was about 7:1 from the 13C NMR spectrum. According to the Fineman-Ross equation, the reactivity ratios of DCPD-MA and DCPD-AA were estimated, as well as series distribution of DCPD-MA and DCPD-AA system and average chain length. These data revealed that MA was hardly to homopolymerization, while DCPD was easier in copolymerization of DCPD/MA. We also deduced that DCPD was more difficult to homopolymerization than AA because of sterich hindrance of DCPD.The copolymers of C9-MA and C9-AA, and the terpolymer of C9-MA-AA were synthesized by radical solution copolymerization. The influences such as reaction temperature, reaction time,and amount of initiator, resolvent and chain transfer on molecular weight of copolymers were investigated. The optimum approach was to use ethanol as resovlent.According to GB/T 16632-1996, the scale-inhibiting performance of copolymers was evaluated and the influences on scale-inhibiting ratio of copolymers were studied by a series of experiments. These experiments indicate that the molecular weight of the copolymer is crucial to scale-inhibiting performance of the copolymers. The scale inhibiting performance of C9-AA water soluble copolymer was evaluated. When 15 mg/L of the prepared copolymer compound is used for simulated cooling water, scale-inhibiting ratio can be above 90% and period of validity can reach 60 hours under the condition of [Ca2+]<600mg/L, pH<9.3.The different technologies of copolymerization were evaluated and the best one was abridged for industry.