A selfdeveloped high⁃pressure CO2⁃crude mixing container is used to mix up CO2 and waxy crude oil respectively under reservoir condition, and gelling and yielding properties of the waxy crude oil are studied by gas chromatograph, DSC, rheological measurement, microscopic observation and other instruments. A brief summery about the effect of CO2 pretreatment on waxy crude oil was given. After treated by CO2, the reduction of light component in the waxy crude oil can inhibit the wax dissolution and increase the wax appearance temperature of waxy crude oil. The size of wax crystals becomes smaller and disperser after treated by CO2, which gives rise to the enhancement of the gel structure and the depravation of the low⁃temperature rheological property. With the increase of the pressure of CO2 during mixing process, the gelling and yielding properties of waxy crude oil are changed more and more obviously.

In this paper, Changqing crude oil was emulsified under pressure in different dissolved gas environments (CO2, CH4, N2) by using crude oil emulsifier with pressure dissolved gas. The solubility (Rs) , water separation rate (fv), interfacial tension (γ), interfacial modulus of elasticity (εd), viscosity of dissolved gas crude oil (μ) and apparent viscosity of dissolved gas crude oil emulsion (μap) were measured by means of solubility measurement device, emulsion stability analysis device, interfacial tension tester and high pressure rheometer. The results show that the presence of oil⁃water interfacial film inhibits the migration of gas from the outer phase to the inner phase to a certain extent, so that the solubility of the dissolved gas oil emulsion is less than the solubility of the internal and external phases. Under the environment of dissolved CO2, because of the minimum interfacial tension between oil and water, the best emulsification effect is obtained, and the W/O emulsion droplets with pressure are the most compact. Under the environment of dissolved CO2, because of its minimum interfacial tension between oil and water, the smallest droplets are formed in W/O emulsion and the emulsifying effect is the best. At the same time, due to the elastic modulus of oil⁃water interface is the largest, the emulsion system is the most stable, and the viscosity ratio of emulsion system is the most obvious than that of crude oil system. In contrast, in the environment of N2 dissolution, the stability of the emulsion system is poor, and it is easy to demulsify.

Based on different proportions of CO2 and CH4 mixture gas source, the experiment pretreated Changqing oil by using selfmade saturated dissolved gas crude oil processing device under simulated stratum conditions, and then saturated dissolved gas crude oil was got through step by step depressurizing under gathering and transportation conditions (0~3.5 MPa). Crude oil's solubility (Rs), volume factor (Bo), condensation point (TZ), viscosity (μ) and yield value (τy) were studied by using highpressure equipment, which could measure properties of live oil, and highpressure rheometer. The results showed that Rs and Bo increased with the increase of pressure. As the temperature increased, Rs decreased and Bo increased. When experiments were conducted with the same temperature and pressure, Rs (CO2) was the double of Rs(CH4), and the Rs of mixture gas was between the two formers, and the crude oil got better expansion effect with the mixture gas. Among mixture gas, molar ratio of 9∶1 (n(CO2)/n(CH4)) had the best expansion effect, and such mixture gas had best improvement of crude oil's condensation point, viscosity and yield value.

Three dodecatungstophosphates were prepared from 1-butyl-3-methylimidazolium bromide, 1-(3-sulfonic group) propyl-3-methylimidazolium, 1-(3-sulfonic group) propyl pyridinium and 12-tungstophosphoric acid. The IR and XRD results of three dodecatungstophosphates demonstrated that all of them contain typical heteropolyanions. Selective oxidation of benzyl alcohol to benzaldehyde with 30%(mass fraction) H2O2 as oxidant was carried out in the absence of organic solvents, phase-transfer catalysts and additives. Effects of different catalysts were studied and reaction conditions were optimized. It is found that 1-butyl-3-methylimidazolium dodecatungstophosphates ［Bmim］3PW12O40 exhibited better catalytic performance. Under [KG*4]the [KG*4]optimal [KG*4]reaction [KG*4]conditions(benzyl [KG*4]alcohol 10 mmol, hydrogen [KG*4]peroxide 30 mmol, catalyst 0.05 mmol, reaction temperature 85 ℃, reaction time 3 h), the conversion of benzyl alcohol was 79.6% and the selectivity of benzaldehyde could reach 95.6%. The catalysts are also proven to have good recycling capability. 