Hydrogenation process for hydrocarbon resins

Details Hydrogenation process for hydrocarbon resins Hydrogenation process for hydrocarbon resins

2002-10-01

2004-06-29

Bell, Mark L. (Department: 1755)

Mineral oils: processes and products

Chemical conversion of hydrocarbons

Hydrogenation

C208S2160PP, C208S25100H, C208S25400R, C502S305000, C502S313000, C502S325000, C528S483000, C528S485000, C528S487000, C528S490000, C525S327900, C525S331900

Reexamination Certificate

active

06755963

ABSTRACT:

TECHNICAL FIELD
This invention relates to a catalytic hydrotreating process useful for hydrocarbon resin and rosin feeds. In particular the invention relates to an improved process for hydrotreating such resins and rosins with hydrogenation metal catalyst compounds having sulfided nickel molybdotungstate catalysts.
BACKGROUND OF THE INVENTION
Hydrotreating processes for the hydrogenation, desulfurization and denitrogenation of hydrocarbon compounds including such compositions of matter as petroleum fuels, white oils, lubricating oil additives and hydrocarbon resins are well known and practiced industrially. In particular, it is known that heterogeneous catalyst systems, those supported on metal oxide supports, can be advantageously used to facilitate this process. Effective reaction rates require that hydrogen gas molecules and the hydrocarbon compounds come into contact with each other in the presence of an active metal catalyst, and those active metal catalysts are typically affixed within the pores of inert supports. It is generally believed that if the pores are of insufficient design the large hydrocarbon molecules are so restricted in movement into, through and out of the pores that reaction rates are diminished. Accordingly there is a large body of knowledge relating to hydrotreating hydrocarbon compounds with heterogeneous catalysts, see for example the description of U.S. Pat. No. 5,820,749, and documents cited therein. A preferred process of the invention uses a catalyst comprising the metals nickel and/or cobalt and one or both of molybdenum and tungsten on the inert support of that invention.
A nickel molybdotungstate catalyst is disclosed in WO 99/03578. The catalyst is prepared by decomposing a nickel (ammonium) molybdotungstate precursor and sulfiding, either pre-use or in situ, the decomposition product. Suggested uses for the catalyst include desulfurization and denitrogenation.
As is apparent from this document, and those it discusses, increased productivity and run times without catalyst degradation is desirable, particularly for hydrocarbon resins, if color, aromaticity, and softening point characteristics can be retained or improved.
SUMMARY OF INVENTION/INVENTION DISCLOSURE
In accordance with this invention there is provided a process for hydrotreating hydrocarbon resins, which process comprises contacting a feedstock comprising a hydrocarbon resin or rosin, under suitable hydrotreating conditions, with a bulk multimetallic catalyst comprised of at least one Group VIII non-noble metal and at least two Group VIB metals and wherein the ratio of Group VIB metal to Group VIII non-noble metal is from about 10:1 to about 1:10. The process according to the invention can achieve increased hydrocarbon resin productivity through increase in throughput volumes and effective catalyst lifetimes.
Hydrocarbon resins prepared from catalytically or thermally polymerized feedstreams and hydrogenated according to the invention exhibit color, aromaticity and softening point characteristics at least equivalent to previously available hydrogenated resins. The process of the invention is desirably practiced with a bulk catalyst consisting of only the combination of the metal species with the active metal components. It is thus usable in fixed bed hydrogenation reactor while avoiding the negative aspects of inert substrate carriers for supporting the catalytically active metal compounds. The absence of carrier substrates largely removes the possibility of halogen accumulation on substrate surfaces that, in turn, can acidify metal catalysts such that additional, progressive cracking of the hydrocarbon resin molecules occurs. This cracking deteriorates important physical properties such as resin softening point, decreases product yields, and reduces effective catalyst life.
BEST MODE AND EXAMPLES OF THE INVENTION
A preferred process according to the invention comprises the step of hydrogenating or hydrotreating (used interchangeably herein) a catalytically or thermally prepared hydrocarbon resin in the presence of the above described catalyst. Any of the known processes for catalytically hydrogenating hydrocarbon resins can be modified in accordance with the invention by substituting the catalyst system of the invention, in particular the processes of U.S. Pat. Nos. 5,171,793, 4,629,766 and 4,328,090 and WO 95/12623 are suitable. Each is referred to and incorporated by reference for purposes of U.S. patent practice, and is referred to for description of polymerization processes, monomer selection, hydrogenation processes, and end use applications of the described resins.
Other patent literature describes suitable processes for modification in accordance with the invention. For example, EP 0 082 726 describes a process for the hydrogenation of petroleum resins from catalytic or thermal polymerization of olefin and diolefin containing streams, using nickel-tungsten catalyst on a gamma-alumina support wherein the hydrogen pressure is 1.47×10
7
−1.96×10
7
Pa and the temperature is in the range of 250-330° C. The feedstreams are said to contain C
5
and/or C
6
olefin and/or diolefin streams, and, for catalytic polymerization, C
8
/C
9
aromatic olefins, e.g., styrene, vinyl benzene and optionally indene. Thermal polymerization is usually done at 160 to 320° C., at a pressure of 9.8×10
5
to 11.7×10
5
Pa and for a period typically of 1.5 to 4 hours. After hydrogenation the reactor mixture may be flashed and further separated to recover the hydrogenated resin. Steam distillation may be used to eliminate oligomers, preferably without exceeding 325° C. resin temperature.
Additional description and information appears in the technical literature. The term hydrocarbon resin as used in the specification and claims include the known low molecular weight polymers derived from cracked petroleum distillates, coal tar, turpentine fractions and a variety of pure monomers. The number average molecular weight is usually below 2000, and physical forms range from viscous liquids to hard, brittle solids. Polymerization feedstreams are derived from the sources described above via various known means and methods of fractionation. Friedel-Crafts polymerization is generally accomplished by use of known Lewis acid catalysts in a polymerization solvent, and removal of solvent and catalyst by washing and distillation. The invention hydrotreating process is particularly suitable for such Lewis acid catalyzed resins due to residual halogen containing reaction products from the polymerization process. Thermal catalytic polymerization is also utilized, particularly for aliphatic, cyclo-aliphatic and aliphatic-aromatic petroleum resins. The preferred hydrocarbon resins are those known to be useful as tackifiers for adhesive compositions, particularly the petroleum resins derived from the deep cracking of petroleum distillates, hydrocarbon resins from pure aromatic monomers, the coumarone-indene resins from coal tar and the polyterpenes derived from turpentine fractions. Included in petroleum resins are those that have been modified with aromatic or terpene containing feedstreams. For additional description of feedstream derivation, monomer composition, methods of polymerization and hydrogenation, reference may be made to patent literature (see Background) and to technical literature, e.g., Hydrocarbon Resins, Kirk-Othmer Encyclopedia of Chemical Technology, v. 13, pp. 717-743 (J. Wiley & Sons, 1995); Encycl. of Poly. Sci. and Eng'g., vol. 7, pp. 758-782 (J. Wiley & Sons, 1987), and the references cited in both of them. Additionally, reference may be made to EP 0 240 253 and its corresponding application U.S. Ser. No. 07/065,792, filed Jun. 27, 1987. All of these references are incorporated by reference for purposes of U.S. patent practice.
The known natural resins will additionally be suitable for hydrotreating in accordance with the invention. The natural resins are traditional materials documented in the literature, see for example, Encycl. of Poly. Sci. and Eng'g., vol

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