Hydroperoxide decomposition processes

Details Hydroperoxide decomposition processes Hydroperoxide decomposition processes

1999-03-25

2001-02-20

Padmanabhan, Sreeni (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Oxygen containing

C568S835000, C568S922000

Reexamination Certificate

active

06191311

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to improved catalytic processes for decomposing alkyl or aromatic hydroperoxide to form a mixture containing the corresponding alcohol and ketone.
BACKGROUND OF THE INVENTION
Industrial processes for the production of mixtures of cyclohexanol and cyclohexanone from cyclohexane are currently of considerable commercial significance and are well described in the patent literature. In accordance with typical industrial practice, cyclohexane is oxidized to form a reaction mixture containing cyclohexyl hydroperoxide (CHHP). The resulting CHHP is decomposed, optionally in the presence of a catalyst, to form a reaction mixture containing cyclohexanol and cyclohexanone. In the industry such a mixture is known as a K/A (ketone/alcohol) mixture, and can be readily oxidized to produce adipic acid, which is an important reactant in processes for preparing certain condensation polymers, notably polyamides. Due to the large volumes of adipic acid consumed in these and other processes, improvements in processes for producing adipic acid and its precursors can be used to provide beneficial cost advantages.
Druliner et al., U.S. Pat. No. 4,326,084, disclose an improved catalytic process for oxidizing cyclohexane to form a reaction mixture containing CHHP, and for subsequently decomposing the resulting CHHP to form a mixture containing K and A. The improvement involves the use of certain transition metal complexes of 1,3-bis(2-pyridylimino)isoindolines as catalysts for cyclohexane oxidation and CHHP decomposition. According to this patent, these catalysts demonstrate longer catalyst life, higher CHHP conversion to K and A, operability at lower temperatures (80°-160° C.), and reduced formation of insoluble metal-containing solids, relative to results obtained with certain cobalt(II) fatty acid salts, e.g., cobalt 2-ethylhexanoate.
Druliner et al., U.S. Pat. No. 4,503,257, disclose another improved catalytic process for oxidizing cyclohexane to form a reaction mixture containing CHHP, and for subsequently decomposing the resulting CHHP to form a mixture containing K and A. This improvement involves the use of Co
3
O
4
, MnO
2
, or Fe
3
O
4
applied to a suitable solid support as catalysts for cyclohexane oxidation and CHHP decomposition at a temperature from about 80° C. to about 130° C., in the presence of molecular oxygen.
Sanderson et al., U.S. Pat. No. 5,414,163, disclose a process for decomposing tertiary-butyl hydroperoxide in the liquid phase over catalytically effective amounts of unsupported titania, zirconia, or mixtures thereof, to prepare the corresponding alcohol. The preparation of corresponding ketones and the use of secondary hydroperoxides are not disclosed.
Further improvements are needed for hydroperoxide decomposition to K/A mixtures in order to overcome the deficiencies inherent in the prior art. Other objects and advantages of the present invention will become apparent to those skilled in the art upon reference to the detailed description which hereinafter follows.
SUMMARY OF THE INVENTION
In accordance with the present invention, improved processes are provided in which a hydroperoxide or secondary hydroperoxide are decomposed to form a decomposition reaction mixture containing a corresponding alcohol and ketone.
The improvement comprises decomposing a hydroperoxide by contacting a hydroperoxide with a catalytic amount of a heterogenous catalyst selected from the group consisting of Nb and Hf hydroxides or oxides. Preferably, the catalyst is supported on a member selected from the group consisting of SiO
2
, Al
2
O
3
, carbon, and TiO
2
.
The improvement also comprises decomposing a secondary hydroperoxide by contacting a secondary hydroperoxide with a catalytic amount of a heterogenous catalyst selected from the group consisting of Zr and Ti hydroxides or oxides. Preferably, the catalyst is supported on a member selected from the group consisting of SiO
2
, Al
2
O
3
, carbon and TiO
2
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides improved processes for conducting a hydroperoxide decomposition step in an industrial process in which an alkyl or aromatic compound is oxidized to form a mixture of the corresponding alcohol and ketone. In particular, cyclohexane can be oxidized to form a mixture containing cyclohexanol (A) and cyclohexanone (K). The industrial process involves two steps: first, cyclohexane is oxidized, forming a reaction mixture containing CHHP; second, CHHP is decomposed, forming a mixture containing K and A. As previously mentioned, processes for the oxidation of cyclohexane are well known in the literature and available to those skilled in the art.
By “hydroperoxide” is meant a compound that contains the functional group —OOH attached to a carbon atom.
By “secondary hydroperoxide” is meant a hydroperoxide in which the carbon atom attached to the —OOH group is further connected to only two other carbon atoms.
By “corresponding alcohol” and “corresponding ketone” is meant the alcohol or ketone compound formed by the direct decomposition of the hydroperoxide fragment without the breaking of any carbon-carbon bonds. For example, cyclohexylhydroperoxide is a secondary hydroperoxide, and its corresponding alcohol and ketone would be cyclohexanol and cyclohexanone.
Advantages of the present heterogenous catalytic processes, relative to processes employing homogenous metal catalysts, such as metal salts or metal/ligand mixtures include, longer catalyst life, improved yields of useful products, and the absence of soluble metal compounds. For example, in one extended experiment, soluble niobium was found to be below a detectable level of 100 ppb.
The improved processes can also be used for the decomposition of other alkane or aromatic hydroperoxides, for example, t-butyl hydroperoxide, cyclododecylhydroperoxide and cumene hydroperoxide.
The CHHP decomposition processes can be performed under a wide variety of conditions and in a wide variety of solvents, including CHHP itself. Since CHHP is typically produced industrially as a solution in cyclohexane from catalytic oxidation of cyclohexane, a convenient and preferred solvent for the decomposition process of the invention is cyclohexane. Such a mixture can be used as received from the first step of the cyclohexane oxidation process or after some of the constituents have been removed by known processes such as distillation or aqueous extraction to remove carboxylic acids and other impurities.
The preferred concentration of CHHP in the CHHP decomposition feed mixture can range from about 0.5% by weight to 100% (i.e., neat). In the industrially practiced route, the preferred range is from about 0.5% to about 3% by weight.
Suitable reaction temperatures for the processes of the invention range from about 80° C. to about 170° C. Temperatures from about 110° C. to about 130° C. are typically preferred. Reaction pressures can preferably range from about 69 kPa to about 2760 kPa (10-400 psi) pressure, and pressures from about 276 kPa to about 1380 kPa (40-200 psi) are more preferred. Reaction time varies in inverse relation to reaction temperature, and typically ranges from about 2 to about 30 minutes.
As noted previously, the heterogenous catalysts of the invention include Nb and Hf hydroxides or oxides for all hydroperoxides and Zr and Ti hydroxides or oxides for secondary hydroperoxides, which can optionally be applied to suitable porous solid supports. The metal oxide to catalyst support can vary from about 0.1 to about 50 percent by weight, and is preferably about 1 to about 25 percent. Suitable supports include SiO
2
(silica), Al
2
O
3
(alumina), C (carbon) or TiO
2
(titania). SiO
2
is a preferred support, and Nb hydroxide or oxide supported on SiO
2
is a presently preferred catalyst of the invention. Some of the heterogenous catalysts of the invention can be obtained already prepared from manufacturers, or they can be prepared from suitable starting materials using methods known in the art. These methods can include sol-gel techniques

Affiliated with

Also associated with

Rating

Hydroperoxide decomposition processes does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Hydroperoxide decomposition processes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydroperoxide decomposition processes will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2568275