Chemical behavior of 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene,and related compounds as a key to understanding the specifics of radiation-chemical processes: 5. Energy-controlled positive-charge transfer processes

The initial radiation-chemical yields of consumption of hydrocarbons G₀(-RH), where RH is 5-vinyl-2-norbornene, 2-ethylidene-2-norbornene, or 2-vinylnorbornane, dissolved in the solvents (L) cyclohexane, carbon tetrachloride, tert-butylamine, and benzene during irradiation of their solutions at 40°C with ⁶⁰Co γ-rays were determined. The G₀(-RH) values were found to be linearly related to the first vertical ionization potentials (PI₁) measured for RH and L in the gas phase by means of photoelectron spectroscopy. It was shown that the RH consumption processes are controlled by species with the highest and lowest PI₁ values. It was concluded that these species are superexcited solvent molecules L** (PI₁ = 15.6–17.8 eV for cyclohexane) and isomeric (distonic) forms of the RH⁺ radical cations, not the parent L and RH molecules, respectively. In the case of RH = VNB, the radical cation in this form contains two allyl systems, of which one is cationic and the other (characterized by PI₁ = 7.1 eV) is radical.     

Chemical behavior of 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene,and related compounds as a key to understanding the specifics of radiation-chemical processes: 2. The structure of polymeric products according to IR data

It was found that the main products of γ-radiolysis (⁶⁰Co) of liquid 5-vinyl-2-norbornene (VNB) and 5-ethylidene-2-norbornene (ENB) and their solutions in cyclohexane and benzene are polymers. The structure of these polymers was determined by means of IR spectroscopy. It was shown that the polymerization of individual VNB engages both C=C bonds of the diene and involves norbornene ring opening. In the case of individual ENB, only one, exo-cyclic, C=C bond participates in polymerization retaining the norbornene ring intact. In cyclohexane solutions, mixtures of VNB and ENB polymers of the same type are formed, which are predominantly composed of saturated compounds. It was found that polymerization during γ-irradiation of VNB solution in benzene proceeds via the addition of benzene radicals to one, endo-cyclic, C=C bond of VNB. The produced 2-vinylnorbornane moiety of this polymer was identified via comparison of its IR spectrum with that of unirradiated 2-vinylnorbornane.     

Chemical behavior of 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, and related compounds as a key to understanding of specifics of radiation-chemical processes: 1. Irradiation of individual compounds and dilute solutions

The effect of ⁶⁰Co γ-radiation on the individual bicyclic dienes 5-vinyl-2-norbornene (VNB) and 5-ethylidene-2-norbornene (ENB) and dilute (0.01–1.0 mol/l) solutions of VNB in heptane, cyclohexane, and benzene was studied. Chain polymerization processes occur in γ-irradiated individual dienes, as indicated by the high initial radiation-chemical yield of diene conversion: G₀(-VNB) = 640 mol/100 eV and G₀(-ENB) = 360 mol/100 eV. At doses higher than 14 Mrad (1 rad = 0.01 Gy), polymer formation processes are accompanied by the reverse processes of depolymerization, which result (in the range of 14–100 Mrad) in the appearance of a plateau (at a polymer content of 14.5%) on the dose dependence of VNB conversion and in a 90-fold decrease in the rate of ENB consumption as compared to the initial (0–14 Mrad) region. It was found that the G₀(-VNB) values fall on a straight line G₀(-VNB) = 620C₀(VNB) in the concentration plots for VNB solutions in heptane and cyclohexane and on another straight line G₀(-VNB) = 180C₀(VNB) for VNB solutions in benzene. These findings are explained in terms of the indirect ionization of VNB molecules in heptane and cyclohexane, since the first ionization potentials equal for the solvents (heptane and cyclohexane) are higher than the ionization potential of VNB, and the involvement of excited benzene molecules in VNB decay processes.     

不同官能团有机物对MoNiP/Al_2O_3催化剂的组成、结构和性能的影响

以Mo和Ni为活性组分、γ-Al_2O_3为载体,采用具有不同官能团的有机物制备了MoNiP/Al_2O_3催化剂。通过H_2-TPR、XRD、原位Raman光谱、CO吸附红外光谱、XPS及HRTEM等方法表征了催化剂的组成和结构。以蜡油为原料,在反应压力11.0 MPa、氢油体积比700∶1、反应温度370℃、液态空速1.0 h~(-1)的条件下评价了催化剂的加氢活性。实验结果表明,添加具有不同官能团的有机物,特别是氨类有机物,改善了载体氧化铝表面羟基基团的分布,促使更多的Mo物种以八面体配位多核聚钼酸形态存在,并有效削弱了载体与活性金属之间的强相互作用,提高了Mo物种的分散度与硫化度,使催化剂形成更多的"Mo-Ni-S"加氢活性相,提高了催化剂的加氢活性。添加氨类有机物的催化剂对蜡油具有更高的芳烃饱和活性、加氢脱硫和加氢脱氮活性。