Olefin Oligomer Composition (Shell Oil Company)

PATENT
Olefin Oligomer Composition (Shell Oil Company)
United States Patent Application 20130123551
Inventors:
De Kraker, Abraham Robert (Sugar Land, TX, US)
Application Number:
13/738572
Publication Date:
05/16/2013
Assignee:
Shell Oil Company (Houston, TX, US)
Abstract:
Processes for the production of an alcohol, esters and aliphatic hydrocarbons are provided. In one embodiment, a process for the production of an alcohol comprises: oligomerizing an olefin or a mixture of olefins having the structural formula Cn-2H2n-3—CH═CH2, wherein n is an integer from 4 to 22, in the presence of an oligomerization catalyst, so as to form a vinylidene containing olefin oligomer; hydroformylating the vinylidene containing olefin oligomer in the presence of a hydroformylation catalyst so as to form a hydroformylated olefin oligomer; and dimerizing the hydroformylated olefin oligomer by means of a Guerbet reaction so as to form the alcohol.
FIELD OF THE INVENTION
The invention relates to hydrocarbon base oils that have properties particularly useful in the area of lubrication. In particular, the present invention relates to base oils having high viscosity indices, low volatility, and good oxidation stability, and to a method for making such oils.
BACKGROUND OF THE INVENTION
Poly Alpha Olefins (PAOs) are known and used as lubricating oils or in lubricating oil formulations. PAOs are typically dimers, trimers and tetramers of 1-octene, 1-decene and/or 1-dodecene and are made by a two-stage process such as that described in U.S. Pat. No. 4,045,507. Alpha olefins can also be oligomerized by metallocene catalyst, as described in U.S. Pat. No. 4,658,078 and U.S. Pat. No. 7,129,197. Other synthetic lubricating oils are esters or alkylated naphthalenes. Highly refined fractions of crude oil are also used as lubricating oils.
Each of these classes of lubricating oils have physical and chemical properties that make them useful as a lubricating oil. Nonetheless, there is still a need for lubricating oils with improved properties. This is particularly the case as the demands on lubricating oils increase.
SUMMARY OF THE INVENTION
The present invention provides a lubricating oil with a combination of physical and chemical properties that is significantly superior to the prior art. Oils in accordance with the invention may be produced in a three-step process comprising 1) oligomerization of an alpha olefin to a vinylidene, 2) hydroformylation to a primary alcohol, and 3) dimerization of the alcohol. The final product can be hydrogenated to form a branched alkane with improved properties as a lubricating base oil. Alternatively, the dimerized alcohol of step 3) above can be used to form an ester with a suitable organic acid, the ester also being useful as a lubricant.
Dimerization of the alpha olefin using metallocene catalyst results in a single vinylidene compound. Hydroformylation of the vinylidene results in three primary alcohol compounds corresponding to hydroformylation at any one of the three terminal carbons of the vinylidene. Dimerization of the alcohol mixture is preferably carried out by the Guerbet reaction, which requires a hydrogen to be present on the carbon beta to the alcohol group. This is true in all cases here, but it has been found that the beta carbon that was originally vinylidene does not react. Thus, of the nine dimers that are possible from the three alcohols, only six are actually formed. The mixture of six isomers, after hydrogenation, is found to have superior viscosity index, volatility, and oxidation stability compared to available lubricating base oils.
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