Catalytical Hydrogenati On Modification Of C9Petroleum Resin For Producing Light Color C9Petroleum Resin And Analysis For The Causes Of Its Color

C9petroleum resin has high molecular weight, high viscosity and contains impurities such as sulfur, chlorine, resulting in a big trouble in hydrogenation modification of the C9petroleum resin due to catalyst deactiviation, especially by a fixed-bed continuous process. So study on the catalyst and reaction process for C9petroleum resin hydrogenation modification is of great important scientific and practical significance.In this paper, hydrogenation modification of C9petroleum resin was carried out by two-stage process with NiWS/γ-Al2O3as the first stage catalyst and PdRu/γ-Al2O3catalyst as the second one, and a series of characteristic technologies, such as H2-TPR, XRD, TEM, XPS were used for in-depth analysis of NiWS/γ-Al2O3and PdRu/γ-Al2O3catalyst before and after the catalytic hydrogenation. The hydrogenation modification is the most important ways to get high-quality petroleum resin, and its color is one of the key indicators that measures quality and performance of C9petroleum resin. So a series of analytical methods such as Raman spectroscopy,1H NMR,13C NMR, DRC-e ICP-MS, were used for in-depth analysis of C9petroleum resin before and after the catalytic hydrogenation. Based on the above works, the main conclusions were drawn as following:1. By DRC-e ICP-MS analysis of C9petroleum resin before and after the catalytic hydrogenation, it is known that the sulfur content of C9 petroleum resin raw materials is very high (about500mg/Kg). High sulfur cotent of C9petroleum resin might be one of the causes why C9petroleum resin shows yellow or amber color, and foul odor, poor thermal stability. A small amount of Br, Hg, Cd, Fe, Ni and other trace heavy metal ions existing in C9petroleum resin may act as the catalyst that induces oxidation or substitution reactions of aromatic rings and the fulvene structure in C9petroleum resin. In sum, the causes of color of C9petroleum resin may be mainly due to the synergy effects of aromatic rings and the fulvene structure, a small amount of inorganic metals, and sulfur, chlorine, bromine and other impurities in C9petroleum resin.2. The NiWS/γ-Al2O3catalyst exhibited excellent desulfurization performance in hydrogenation pretreatment of C9petroleum resin, avoiding the PdRu/γ-Al2O3catalyst at second stage from poisoning by sulfur or other impurities, and therefore greatly extending the life of PdRu catalyst. NiWS/γ-Al2O3catalysts might lead scission of carbon chain of C9petroleum resin when reaction temperature is higher than533K. TEM results showed that the morphology and size of metal particles of the two kinds of catalysts remained almost unchanged after the reaction of1204hours, accounting for their good catalytic stability.3. The colorless C9petroleum resin was obtained by two-stage catalytic hydrogenation over NiWS/γ-Al2O3and PdRu/γ-Al2O3catalyst in series. The hydrogenated petroleum resin became colorless, transparent, and stable and its color remain unchanged after being heated at393K for100hours in atmosphere. The optimum Ni/W atomic ratio was found close to0.23for NiWS/γ-Al2O3catalyst at first stage, while the optimum Pd/Ru atomic ratio was close to3.80for PdRu/γ-Al2O3catalyst at second stage.4. XRD, TEM and XPS characterization results of the NiWS/γ-Al2O3and PdRu/γ-Al2O3catalyst show that a certain relationship exists between the structure of the catalyst surface and hydrogenation activity:WS2crystallites over the sulfided1.5NiO20WO3/γ-Al2O3catalyst show shorter particle length and more layer number; the particle length is about to3-4nm and the layer number is about to3-4. XPS results show that the sulfided1.5NiO20WO3/γ-Al2O3catalyst exhibits the highest content of NiSWO and smallest FWHM(Full Width Half Maximum):NiSWO content is46.04%and FWHM is equal to2.8. The TEM views reveal the presence of hompgeneously dispersed PdRu particle on the support, and the PdRu particle diameter is about to3-5nm. The reduced Pd binding energy increased by0.5eV compare to that of the standard Pd, showing hydrogenation capacity of the Pd-based catalyst is obviously increased by addition of Ru.5. By Raman spectrum analysis of C9petroleum resin before and after the catalytic hydrogenation, we can see that sulfur exists in the form of aromatic substitution (υC-S), while the sulfide (υS-S) and thiosulfate aliphatic hydrocarbons (υC-S) are small or nonexistent. By comparing the Raman spectra of C9petroleum resin before and after the catalytic hydrogenation, it can be seen that the benzene ring of C9petroleum resin has completely saturated after hydrogenation, while the sulfur, bromine and other impurities in C9petroleum resin were largely removed.6. Pyrolysis C9fraction still contains a certain amount of hydrogen sulfide, sulfur indene and its derivatives. In the polymerization process, the sulfur indene and its derivatives not only affect the petroleum resin color but also affect the smell of petroleum resin. It is believable that the unpleasant smell of petroleum resin is mainly due to the attendance of hydrogen sulfide produced from decomposition of sulfur compounds. In this paper, the formation process and removal mechanism of sulfur indene and its derivatives in C9petroleum resin was analyzed, in which sulfur indene and its derivatives first is hydrogenated with the formation of R-SH, and then R-SH is again hydrogenated with the release of H2S.7. The colorless C9petroleum resin was obtained by two-stage catalytic hydrogenation over NiWS/γ-Al2O3and PdRu/γ-Al2O3catalyst in series. After catalytic hydrogenation, benzene and olefin resin were completely saturated and the sulfur, chlorine, bromine and other impurities were basically removed; meanwhile the hydrogenated petroleum resin become colorless, transparent, stable, and its color remain unchanged after being heated at393K in100hours in atmosphere.