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Dimethyldioxirane (DMD) pre-treatment of Massion Pine dissolving pulp has been studied in order to improve the effect of hydrogen peroxide bleaching. The influence of the dosage of acetone and peroxymonosulfate (PMS), the ratio of acetone to PMS, temperature and time of reaction were studied. The optimum parameters of DMD pre-bleaching process were at the 0.7% dosage of acetone and PMS while the ratio of the two was 3:4, and pretreated at 60℃ for 100 minute. Pretreated with DMD at this condition, the brightness of final pulp increased 11.14% and the content of α-cellulose increased 9.62% compared with the pulp which bleached by hydrogen peroxide without DMD pretreatment.

Dissymmetric bis-quaternary ammonium with imidazoline ring was evaluated for corrosion inhibition efficiency against Q235 steel in 1.0mol•L-1hydrochloric acid solution at room temperature (298K) by gravimetric method, potentiodynamic polarization, electrochemical impedance spect- rum(EIS) and quantum chemical calculation. The results of mass loss and polarization data showed the compound acted as a very good mix-up inhibitor for Q235 steel in 1.0mol•L-1hydrochloric acid solution. EIS results showed that the associated values of the charge transfer resistance (Rct) increase by increasing the additive concentrations and immersing time whereas the associated values of double layer capacitance (Cdl) decrease. These changes in the impedance parameters (Rct and Cdl) are indicative of adsorption of the compound on Q235 steel surface leading to the formation of a protective film. The obtained correlations and Quantum chemical calculations conclusions agree well with the experimental results.

Imidazoline derivative inhibitors are successfully used in oil-gas field for CO2 and H2S corrosion. The inhibition performance and inhibition mechanism of imidazoline with thioureido to prevent corrosion of steel in saltwater saturated with CO2 were studied by polarization curves and electrochemical impedance spectroscopy (EIS), in the meantime, quantum chemical analysis was used to analysis the results. The results of electrochemical measurements indicated that the inhibitor belonged to mixed-type inhibitor which mainly inhibited anodic process and worked as “negative catalysis”. The inhibition efficiencies increased then decreased with the increase in inhibitor concentration. The electrochemical results have also been supplemented by quantum chemical analysis. It was found that the chemical adsorption of the imidazoline with thioureido molecule on Q235 steel depended on the imidazoline ring and thioureido, thus the inhibitor had good corrosion inhibition.