Process for selective catalytic oxidation of olefins to...

Details Process for selective catalytic oxidation of olefins to... Process for selective catalytic oxidation of olefins to...

2000-02-11

2001-10-16

Nazario-Gonzalez, Porfirio (Department: 1621)

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

Organic compounds

Oxygen containing

C568S485000, C502S167000

Reexamination Certificate

active

06303828

ABSTRACT:

The present invention relates to the use of certain organorhenium compounds for the selective catalytic oxidation of olefins to the corresponding carbonyl compounds with cleavage of C═C bonds, and to a process therefor.
The dominant methods for oxidizing olefins to carboxylic acids and aldehydes with cleavage of C═C bonds are still those characterized by stoichiometric use of the oxidizing agent (CrO
3
/H
2
SO
4
, manganese compounds, RuO
4
). These processes suffer not only from the ecological and economic problem of the production of inorganic salts, which makes elaborate and thus costly purification of the wastewater necessary, but also from a lack of acceptability in health and pharmacology terms, and a lack of selectivity concerning the synthesis of aldehydes. In addition, oxidation with these reagents results exclusively in carboxylic acids because the aldehydes produced as intermediates undergo immediate further reaction and cannot be isolated.
The only systems which can be said to be efficient to date in the area of catalytic processes for cleavage of C═C bonds are those in which ruthenium compounds are employed as catalysts (R. A. Sheldon, J. Kochi, Metal-Catalyzed Oxidation of Organic Compounds, Academic Press, New York, 1981). However, the advantage of a catalytic process in oxidative chemistry becomes really evident only when the primary oxidizing agent employed is ecologically acceptable. Ruthenium compounds have the disadvantage in this respect of being incompatible with the ecologically acceptable hydrogen peroxide as primary oxidizing agent (reaction product water), because with this there is rapid, and sometimes even explosive, decomposition. The oxidizing agents which are therefore employed in conjunction with ruthenium complexes (peracetic acid, NaOCl, NalO
4
etc.) on the one hand prove to be complicated and costly in process engineering terms (peracetic acid), and on the other hand are unable to solve the problem of the production of inorganic salts in the stoichiometric oxidation (NaOCl, NalO
4
etc.). In addition, control of the ruthenium-catalyzed oxidations to give aldehydes is impossible because they are rapidly oxidized further to carboxylic acids.
Thus, in particular, access to aliphatic aldehydes has hitherto been essentially reserved to the hydroformylation reaction, which likewise starts from the olefins obtainable from the SHOP process but, in contrast to the bond-cleaving oxidation, generates the required aldehyde by extending the carbon chain using carbon monoxide.
Transition metals which are compatible with hydrogen peroxide (Mo, W, Re) are at present suitable only for epoxidation in good yields. Cleavages of C═C bonds take place, if at all, only with poor yields (C. Venturello, M. Ricci, J. Org. Chem. 1986, 51, 1599; G. W. Parshall, U.S. 3646130). These systems are, however, unsuitable for selective generation of aldehydes.
In the area of rhenium chemistry, studies by Buchler et al. (DE-A-373 189, DE-A-3 731 690) have shown that rhenium complexes are capable of epoxidizing alkenes.
EP-A-380 085 discloses organorhenium compounds which are employed as catalysts for oxidizing olefins to the corresponding epoxyalkanes and diols in the presence of hydrogen peroxide.
Where EP 0 380 085 relates to oxidation to carbonyl compounds, this takes place either without cleavage of bonds, or has been demonstrated only for the oxidation of stilbene. G. W. Parshall is able with the Re
2
O
7
/H
2
O
2
system to oxidize cyclododecane to 1,12-dodecanoic acid (U.S. Pat. No. 3,646,130), although the selectivities are economically unacceptable.
The object therefore is to find an efficient catalyst system which makes the corresponding carbonyl compound, in particular the aldehyde, as the missing link in the chain of oxidation olefin-epoxyalkane or alkanediol-alkanal-alkanoic acid, available in high selectivity with cleavage of C═C double bond in the olefin employed.
It has been found that certain organorhenium compounds are suitable as highly active catalysts for the oxidation of olefins selectively to aldehydes or ketones with cleavage of the C═C double bond when they are used with peroxide-containing compounds in a liquid medium. This is all the more surprising since the rhenium catalysts employed have to date been distinguished, besides their high activity (W. A. Herrmann, R. W. Fischer, D. W. Marz, Angew. Chem. 1991, 103, 1706), very particularly by their high selectivity for the oxidation of olefins to the epoxides and, where appropriate, to the diols formed subsequently by hydrolysis.
The invention thus relates to the use of compounds of the formula
R
1
a
Re
b
O
c
•L
d
  (I),
in which
a=zero or an integer from 0 to 6
b=an integer from 1 to 4
c=an integer from 1 to 12
d=an integer from 0 to 4
L=Lewis base
and the total of a, b and c is such as to comply with the penta-or hepta-valency of rhenium, with the proviso that c is not greater than 3•b, and in which
R
1
is absent or identical or different, and is an aliphatic hydrocarbon radical having 1 to 20 and preferably having 1 to 10 carbon atoms, an aromatic hydrocarbon radical having 6 to 20 and preferably having 6 to 10 carbon atoms or an arylalkyl radical having 7 to 20 and preferably having 7 to 9 carbon atoms, where the R
1
radicals can, where appropriate, be substituted identically or differently, independently of one another, and in the case of &dgr;-bonded radicals at least one hydrogen atom is still bonded to the carbon atom in the &agr; position, as catalysts for the selective oxidation of olefins with cleavage of C═C bonds to give the corresponding carbonyl compounds in the presence of a peroxide-containing compound, where the amount of substance ratio of olefinic double bond to peroxide-containing compound is in a range from 1:2 to 1:14.
The present invention further relates to a process for the selective oxidation of olefins to the corresponding carbonyl compounds with cleavage of C═C bonds, where the olefins are oxidized in the presence of a catalyst of the formula I
R
1
a
Re
b
O
c
•L
d
  (I),
in which R
1
, a, b, c, d and L have the abovementioned meaning, in a liquid medium with a peroxide-containing compound, and the amount of substance ratio of olefinic double bond to peroxide-containing compound is in a range from 1:2 to 1:14.
FIG. 1
shows for the example of compounds of the formula RReO
3
how they can be employed as adaptable catalysts for epoxidation, vicinal dihydroxylation and cleavage of C═C bonds with selective generation of aldehydes.
The compounds of the formula (I) may also be in the form of their Lewis base adducts. Typical examples of Lewis bases are pyridine, bipyridine, t-butylpyridine, amines, in particular secondary and tertiary amines such as triethylamine and quinuclidine, H
2
O and polyethers such as, for example, diglyme.
An aliphatic hydrocarbon radical R
1
means alkyl radicals having 1 to 20 and preferably having 1 to 10 carbon atoms, alkenyl or alkynyl radicals having 2 to 20 and preferably having 2 to 10 carbon atoms, cycloalkyl or cycloalkenyl radicals having 3 to 20 and preferably having 3 to 10 carbon atoms. Suitable examples of R
1
are alkyl radicals such as methyl, ethyl, propyl, isopropyl and the various butyl, pentyl, hexyl, octyl radicals such as ethylhexyl and decyl radicals, and alkenyl radicals such as allyl; also suitable are cycloalkyl radicals such as cyclopropyl, cyclobutyl, cyclopentyl, alkylated cyclohexyl such as hydrogenated tolyl, xylyl, ethylphenyl, cumyl or cymyl, 1-menthyl and 1-norbornyl, and alkenyl radicals such as vinyl and allyl and cycloalkenyl radicals such as cyclopentadienyl and pentamethylcyclopentadienyl, with methyl being particularly preferred.
Suitable examples of an aromatic hydrocarbon radical R
1
are phenyl or naphthyl. Benzyl may be mentioned as example of an arylalkyl radical.
The radical R
1
can also be substituted. Examples of suitable substituents are fluorine, chlorine, bromine, NH
2
, NR
2
2
, PH
2
, PHR

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