VIA HYDROFORMYLATION

Filed of the Invention The present invention relates generally to hydrofor¬ mylation in which carbon monoxide and hydrogen are reacted with an olefin, the reaction also frequently being referred to as the "oxo" process. More particularly, the invention relates to a hydroformylation process for manu¬ facturing 1-hydroxymethyl polyolefin which comprises reacting carbon monoxide and hydrogen with a polyolefin in the presence of a cobalt containing catalyst, the polyole¬ fin reactant being obtained by cationic polymerization of a 1-olefin containing feed, and having a degree of polym¬ erization of greater than 6. As a composition of matter, the present invention is directed to 1-hydroxymethyl polyolefin, the hydroformylation reaction product obtained by reacting a polyolefin having a degree of polymerization greater than 6 with carbon monoxide and hydrogen in the presence of a cobalt containing catalyst.

Background Discussion

Hydroformylation is a common industrial reaction used to selectively transform an olefin to either an aldehyde or an alcohol. See R. A. Sheldon, Chemicals From Synthe¬ sis Gas, D. Reidel Publishing Co., Boston (1983). Hydro- formylation is used to form a large variety of chemical intermediates from butyraldehyde to detergent alcohols.

Polyolefins, such as polybutene and polypropene having degree of polymerization greater than 6 are com¬ monly employed as building blocks in the manufacture of a wide variety of chemical intermediates. Their preparation ^• by polymerization of 1-olefin containing feedstocks using catalysts such as aluminum chloride and boron triflouride is disclosed extensively in the patent and technical lit¬ erature. It is well known that the termination step in the polymerization of isobutylene to polybutene results in a "terminal" double bond which imparts desired reactivity to the polymer for subsequent reactions, such as epoxida-

tion or reaction with maleic anhydride. However a problem exists in that the termination step can place the terminal double bond in a highly reactive 1,1 disubstituted posi¬ tion (i.e., vinylidene) or in a much less reactive inter¬ nal trisubstituted or tetrasubstituted position.

The presence of less reactive internal trisubstituted and tetrasubstituted double bond is particularly a problem where it is desired to introduce a reactive primary alco¬ hol group at the olefinic site of the polyolefin. Although many processes will transform a polyolefin, such as polybutene, into an alcohol, the alcohol group will have the desired primary (thus more reactive) character only if the double bond of the olefin is externally located as in Figure 1 below. If the double bound is located internally as in Figure 2, then the alcohol group generally will be secondary and less reactive.

Figure 2

For example, hydroboration will transform only an external olefin group into a primary alcohol. If hydrobo¬ ration is applied to polybutene, the presence of internal trisubstituted olefin sites in the polybutene will result in secondary alcohol groups. The same problem results if one uses a two-step epoxidation-hydrolysis scheme.

Given the problem noted above, a principle objective underlying our work was to discover a method for adding an OH group to the reactive end of a polyolefin molecule in such a manner that the resulting alcohol is all primary, regardless of whether the double bound of the polyolefin is external (1,1 disubstituted) or internal (trisubsti¬ tuted). Other objects will be apparent hereinafter to those skilled in the art.

Summary of the Invention We have now found that hydroformylation chemistry can be used to accomplish the above stated objective. In par¬ ticular our invention is a hydroformylation process for manufacturing 1-hydroxymethyl polyolefin which comprises reacting carbon monoxide and hydrogen with a polyolefin in the presence of a cobalt containing catalyst, said poly¬ olefin being obtained by cationic polymerization of a 1-olefin containing feedstock and having a degree of polymerization of greater than 6. The invention is also directed to a composition of matter, namely the hydrofor¬ mylation reaction product obtained by reacting carbon monoxide and hydrogen with a polyolefin having degree of polymerization greater than 6, in the presence of a cobalt containing catalyst, said reaction product comprising pre¬ dominantly 1-hydroxymethyl polyolefin.

The product of the invention, 1-hydroxymethyl polyo¬ lefin is essentially a polyolefin chain end-capped with a hydroxymethyl group, unlike other alcohols derived from polyolefins, the alcohol products obtained in the present inventionsre essentially entirely primary. Primary alco¬ hols are much more reactive than more hindered secondary or tertiary alcohols.

The results of the present invention are particularly surprising if one considers the structure of a polyolefin such as polybutene. For example, polybutene of molecular weight 950 generally contains one double bound for about

every 18-20 monomer groups, i.e., a maximum olefin concen¬ tration of about 5 percent. In addition, as much as 70 percent of the double bonds can be the less reactive internal trisubstituted bonds. Hydroformylation reactions are known to proceed fastest with unsubstituted terminal olefins such as 1-hexene, the rate being proportional to the total olefin concentration. In addition, theore¬ tically the trisubstituted internal double bond found in polyolefins such as polybutene should be 30 times less reactive than terminal olefins such as 1-hexene typically used in hydroformylation or so called "oxo" chemistry. Thus, given low olefin concentration and high degree of internal olefinicity, a polyolefin such as polybutene would not be viewed as a likely candidate for hydroformy¬ lation. Surprisingly, we found that polyolefins such as the normal commercial grades of polybutene ranging in molecular weight from about 250 to about 10,000, could be hydrofor ylated to achieve quantitative double bond con- version with high selectivity (about 72 percent) to 1-hy- droxymethylated products.

The 1-hydroxymethylated product is a mixture of methyl substituted primary alcohols, NMR indicating that in the case of polybutene _r 3-methyl-l-hydroxymethyl poly- butene is the major iso er. No secondary, tertiary, or neopentyl alcohol groups were found in the product. Molecular weight determinations indicate that there is no significant degradation of polyolefin during the hydrofor¬ mylation process. Infrared and NMR analysis further indicate that at least 90 percent of the 1-hydroxymethyl polyolefin pro¬ duced according to the present invention is linear to C_. and about 70 percent is linear to C.. This is important because the reactivity of an alcohol group is effected significantly by substitution at the first and second carbon adjacent to the hydroxyl group. The majority of the 1-hydroxymethyl polyolefin of the present invention is

not substituted until C_ and thus exhibits the reactivity of primary alcohols. Thus, in accordance with the invention, hindered olefins in polyolefin molecules such as polybutene can effectively be converted into reactive primary alcohols.

1-Hydroxymethyl polyolefin is useful in a number of applications where oxo alcohols are presently used. These include areas such as vinyl plasticizers, detergents, sur- factants, adhesives, coatings and lubricating oil addi¬ tives. A specific use would be that of improving the water repellency of polyurethane and polyester coatings.

Detailed Description The polyolefin used in the hydroformylation process of the present invention can be obtained in a well known manner via cationic polymerization of a 1-olefin contain¬ ing feedstock wherein the olefin is preferably a 3-16 carbon monomer. The polyolefin may be prepared from a feed which may be pure 1-olefin or from a feed comprising a mixture of olefins. A preferred polyolefin for use in the present invention due to cost and availability is polybutene. Polybutene can be prepared in a well known manner using a feed of pure isobutylene or a mixed C . hydrocarbon feedstock such as that resulting from the thermal or catalytic cracking operation and conventionally known as a butadiene or C . raffinate. Polybutene suitable for use in the present invention can be obtained from Amoco Chemical Company, Chicago, 111. under the tradename "Indopol" polybutenes. The reader is referred to Schmidt et al. U.S. Pat. No. 4,620,049 for a discussion of poly¬ butene manufacture.

Another suitable olefin for use in the hydroformyla¬ tion process of the present invention is viscous polypro- pene as described in Schmidt U.S. Patent 4,777,317.

An important feature of the present invention is the unexpected finding that polyolefins such as polybutene or

polypropene can be successfully hydroformylated in a manner similar to non-polymeric olefins where olefin con¬ centration is much higher, and the double bond much more successible for reaction, than in polyolefins. Thus the present inventions pertains to polyolefins having degree of polymerization greater than 6.

Although it is unexpected that polyolefins having a substantial amount of internal olefinicity could be con- verted to all primary 1-hydroxymethyl polyolefin, the invention need not be limited to polyolefins having a sub¬ stantial amount of hindered olefin bonds. Polybutene having a high vinylidene content, as for example disclosed in U.S. Patent 4,152,499 can also be used in the present invention.

In the process of the invention, the polyolefin is reacted with carbon monoxide and hydrogen in the presence of a cobalt catalyst, preferably cobalt carbonyl and cobalt carbonyl chloride. These can be used as such or generated in the reactor by a variety of well established methods. Cobalt carbonyl forms when soluble cobalt salts such as cobalt carboxylates, cobalt nitrates, etc. are placed under an atmosphere of CO and H-. Catalyst concen¬ tration in the reaction medium can range from about 0.01 to 5% by weight and preferably between about 0.05 and 4%. In the hydroformylation process of the present invention the ratio of H~ to CO influences the ratio of alcohol to aldehyde in the reaction products. For forma¬ tion of the alcohol product a hydrogen-rich blend of H- and CO is preferred. A H-ϋCO ratio of 2:1 is preferred although ratios between 1 and 3 can be used.

The process of the invention can be carried out at temperatures ranging from about 100°C to about 250°C and at pressures of about 500 to about 10,000 psi. Preferred operating conditions are about 125°C to about 225°C and 1000 to about 5000 psi. The most preferred operating con-

ditions for preparation of 1-hydroxymethylpolybutene are 150°C-200°C and 1250 to 4000 psi.

Any inert solvent can be employed in the reaction medium to aid processing. Solvents in which the catalyst and polybutenes are soluble may be used. Preferred sol¬ vents are aromatic and saturated hydrocarbons such as toluene and hexane.

While polybutene is a preferred olefin for use in the present invention, polypropenes having degree of polymeri¬ zation greater than 6 synthesized by the aluminum chloride catalyzed polymerization of a C- stream, are a suitable starting material. Hydroformylation of this material under the aforementioned conditions yields 1-hydroxymeth- yl-polypropene. Polypropenes can be readily manufactured or obtained commercially from Amoco Petroleum Additives Company, Clayton, MO.

EXAMPLE A solution was prepared containing 42.80 g toluene, 45.01 g polybutene having Mn of about 950 and .88 g cobalt carbonyl catalyst. Following dissolution of the above reactants the reaction solution was sparged with nitrogen for 5 minutes and then charged to a 300 cc autoclave, fol- lowed by additional nitrogen sparging at 45 psi. To the autoclave was then added a mixture consisting of 2 (molar) parts H- and 1 part CO in an amount sufficient to increase the pressure in the autoclave to 2000 psi. A 1-liter bal¬ last tank was pressured to 3000 psi with the H-/CO gas mixture. The autoclave was then heated to 185°C and then pressured to 3000 psi using the ballast tank. The mixture was reacted for 2.5-3 hours. The autoclave was then allowed to cool overnight. The following day the system was vented slowly and the reaction mixture was transferred to a suction flask and purged with nitrogen. The product was then stripped to remove toluene and eluted through a column of alumina. The product was then finally stripped

and dried in a vacuum system equipped with a diffusion pump for approximately 7 hours. The product, a light brown viscous liquid was then analyzed using proton NMR

13 C NMR and IR. Analysis indicated the product contained about 70% 1-hydroxymethyl polybutene. Hydrogenated poly¬ butene and an ester, poly-(butyl)pol (butylate) were the principal by-products.