降低异戊烷的碘值和酸值方法的研究

利用酸值和碘值测定的标准方法对大庆油田化工有限公司轻烃分公司提供的6个异戊烷样品的酸值和碘值进行分析,并与合格产品对比,研究了异戊烷样品的酸值和碘值。依据异戊烷样品酸值和碘值偏高的原因．设计了多层KOH填充柱法和浓硫酸处理法,利用该方法对异戊烷样品进行处理。处理后试样品的酸值和碘值均优于合格品。     

The catalytic reactions of n-pentane and 1-pentene on different molybdenum oxides and metal surfaces

Catalytic reactions of n-pentane and 1-pentene were performed as a function of reaction temperature, on different molybdenum oxides and metal surfaces. These oxides such as Mo₂O₅ and MoO₂ were obtained following the exposure of MoO₃/TiO₂ to hydrogen at different temperatures up to 673 K. Metallic Mo(0) state is obtained at reduction temperatures beyond 723 K. Identification of the Mo chemical species was performed using in situ XPS-UPS surface techniques. The combination of both techniques provides valuable information on the chemical composition of the upper 10 atomic monolayers. X-ray diffraction and HRTEM techniques were also employed. The reduction procedure of MoO₃ does not follow the same pathway when it is deposited on an Al₂O₃ support. A strong electronic interaction between the two species promotes the formation of an Al₂(MoO₄)₃ complex as revealed by XRD measurements. Catalytic active functions present on the different Mo species surfaces are of the acidic type (Lewis and Brönsted) on Mo₂O₅, metal-acid (bifunctional) on MoO₂ and metal function on metallic Mo(0). Consequently, a specific catalytic reaction of n-pentane, such as hydroisomerization to iso-pentane, which is rationalized in terms of a bifunctional mechanism, is expected to occur on MoO₂. Different isomerization reactions of 1-pentene were obtained in the case of MoO₃/TiO₂ and MoO₃/Al₂O₃ at reduction temperatures below 573 K. However, in the case of Mo on the alumina support, the conversion of 1-pentene to iso-pentane is low and irreproducible, contrary to what has been observed for Mo on titania.