Post 245942 (https://www.thevespiary.org/talk/index.php?topic=12139.msg24594200#msg24594200)
(twodogs: "New method for P2P", Novel Discourse) are fraught with pitfalls and I sure don't want to waste my analytical grade $80 a liter PhCHO. Also I have been searching the internet for other catalysts other than Hydrogen Chloride which would be suitable for this type reaction to no avail. Any references or pointers would be highly appreciated. The Organic Reactions volumes referenced don't seem to be available on-line and the Patents referenced aren't very helpful. Anyway I will try it on a small scale soon and will let you all know how it turns out.J. Am. Chem. Soc. 907 (1946) (https://www.thevespiary.org/rhodium/Rhodium/pdf/peracid.pdf)
(https://www.thevespiary.org/rhodium/Rhodium/pdf/peracid.pdf)Post 208702 (https://www.thevespiary.org/talk/index.php?topic=7285.msg20870200#msg20870200)
(Antoncho: "The easiest synth of benzaldehyde from toluene", Chemistry Discourse)Post 446838 (https://www.thevespiary.org/talk/index.php?topic=12194.msg44683800#msg44683800)
(GC_MS: "SPC/SPB", Novel Discourse) ............Read this Chilly Willy and if you or anyone else has acess to(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_imgs/pdf.gif)
(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_imgs/pdf.gif)
In the patent twodogs cited where he got the idea of using perborate it states ......(paraphrased)near quantitative yields of the B/V product can be achieved in the oxidation by appropriate recycling..........
That's it no experimental, examples, discussion, nothing.
Will be making a few more runs with the MePhBuO soon and will try some recycling ideas at small test scale. Ah.... so many reactions so little time...
Actually, the segment in the patent to which you refer goes like this:
The present invention provides a safe and economical process for oxidizing aldehydes and ketones using an alkali metal perborate, such as sodium perborate, as the oxidant. Alkali metal perborates are safe and economical to use, and the sodium borate by-product thus formed is safely handled and is a valuable product that can be sold in its own right. In addition, the oxidation is carried out under easily maintained reaction conditions and provides selectivities approaching 100% so that all of the starting aldehydes or ketones can be converted to final product by appropriate recycling. It can be seen that the use of the alkali metal perborate provides a substantial advance in the oxidation of aldehydes and ketones.
All the authors are trying to say is that because the use of sodium perborate is so exceptionally selective, there won't be any byproducts to the reaction, and whatever starting materials are left over--in this case, the intermediate aldol condensation product of benzaldhyde and MEK--can be reused in another sodium perborate Baeyer-Villiger reaction.
Anyway, that's my interpretation. I could be wrong.
Here's the a text copy of the patent in question, for all those who would like to read it:
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United States Patent 4,988,825
Bove January 29, 1991
Oxidation of aldehydes and ketones using alkali metal perborates
Abstract
Aldehydes and ketones, other than acetone, are oxidized with an alkali metal perborate in the presence of an acid.
Inventors: Bove; John L. (Ridgewood, NJ)
Assignee: Cooper Union Research Foundation, Inc. (New York, NY)
Appl. No.: 910615
Filed: September 23, 1986
Current U.S. Class: 549/272; 549/273; 549/295; 560/231; 562/528
Intern'l Class: C07D 313/18; C07D 313/04
Field of Search: 549/272,273,295 562/528 560/231
References Cited [Referenced By]
U.S. Patent Documents
3122586 Feb., 1964 Berndt et al.
3154586 Oct., 1964 Bander et al.
3483222 Dec., 1969 Sennewald et al.
3716563 Feb., 1973 Brunie et al. 549/524.
3833613 Sep., 1974 Field 549/272.
4160769 Jul., 1979 Higley.
4213906 Jul., 1980 Mares et al. 549/272.
4286068 Aug., 1981 Mares et al. 549/272.
4338260 Jul., 1982 Schirmann 260/502.
Foreign Patent Documents
1096967 Dec., 1967 GB 549/272.
Other References
Y. Ogata et al., Bulletin of the Chemical Society of Japan, vol. 52(2), (1979), pp. 635-636.
A. Baeyer et al., Ber., 1899, 32, 3625-3633.
A. Baeyer et al., Ber., 1900, 33, 858-864.
Ogata et al., Chem. Abst. 90:167685, (1979).
McKillop et al., Tetrahedron Letters, 24, No. 14, (1983), 1505-1508.
McKillop et al., Tetrahedron, 43, pp. 1753-1758 (1987).
A. Rashid et al., J. Chem. Soc. (C) (1967), pp. 1323-1325.
Description
The present invention is directed to the oxidation of aldehydes and ketones to the corresponding acids and esters, respectively using an alkali metal perborate as the oxidant.
The oxidation of ketones, including cyclic ketones, to esters through the use of peracids is known as the Baeyer-Villager Reaction (A. Von Baeyer and V. Villager, Ber., 1899, 32, 3265; 1900, 33, 858) While widely applied, particularly for the oxidation of cyclohexanone to epsilon-caprolactone, nevertheless the use of a peracid presents problems of safety and disposal and/or recycling of organic compounds.
The present invention provides a safe and economical process for oxidizing aldehydes and ketones using an alkali metal perborate, such as sodium perborate, as the oxidant. Alkali metal perborates are safe and economical to use, and the sodium borate by-product thus formed is safely handled and is a valuable product that can be sold in its own right. In addition, the oxidation is carried out under easily maintained reaction conditions and provides selectivities approaching 100% so that all of the starting aldehydes or ketones can be converted to final product by appropriate recycling. It can be seen that the use of the alkali metal perborate provides a substantial advance in the oxidation of aldehydes and ketones.
In particular, the present invention provides a method of preparing acids or esters, which comprises oxidizing an aldehyde (other than acetone) or a ketone with an alkali metal perborate in the presence of an acid.
With the exception of acetone, the present invention is applicable to the oxidation of aldehydes and ketones to form the corresponding esters and/or acids. Aromatic and aliphatic aldehydes and ketones may be used, such as benzaldehyde and methylethyl ketone and the like, as well as cyclic ketones, such as cyclohexanone and the like. Aliphatic and cycloaliphatic aldehydes and ketones containing olefinic unsaturation may likewise be employed to form the corresponding unsaturated ester and/or acid. When ketones are oxidized according to the present invention, the product obtained will be the corresponding ester, but in some cases a mixture of the ester and acid will be produced.
In a preferred embodiment, the present invention may be used for the preparation of esters and/or acids of the formula (I) ##STR1## which comprises reacting an aldehyde or ketone of the formula (II) ##STR2## wherein R.sup.1 is alkyl or aryl, R.sup.2 is hydrogen, alkyl or aryl, or R.sup.1 and R.sup.2 are both hydrogen, or R.sup.1 and R.sup.2 together represent alkylene, provided that R.sup.1 and R.sup.2 may not both be methyl. When R.sup.1 and R.sup.2 is alkyl, R.sup.1 and R.sup.2 may be straight or branched chain alkyl, suitably straight or branched chain alkyl of from 1 to about 15 carbon atoms, such as from 1 to about 10 carbon atoms. When R.sup.1 or R.sup.2 is aryl, R.sup.1 and R.sup.2 may be aryl of from 1 to about 4 rings, including fused rings, and may suitably contain from about 6 to about 30 carbon atoms. Suitably, R.sup.1 or R.sup.2 maybe phenyl, naphthyl, biphenyl and the like. When R.sup.1 and R.sup.2 together represent alkylene, the alkylene may suitably be straight or branched chain alkylene of from about 1 to about 15 carbon atoms in the carbon-to-carbon chain, such as from 1 to about 10 carbon atoms in the carbon-to-carbon chain. Usually when R.sup.1 and R.sup.2 together represent alkylene, there will be from about 1 to about 30 carbon atoms in total, preferably from about 3 to about 15 carbon atoms in total.
In the above formulas (I) and (II), alkyl and alkylene may be unsubstituted or substituted by aryl, halogen, nitro or the like, while the aryl may be substituted by alkyl, preferably lower alkyl, i.e. from about 1 to about 6 carbon atoms, halogen, nitro or the like.
Preferably, R.sup.1 may represent alkyl of from about 1 to about 10 carbon atoms, phenyl, or alkylene of from about 3 to about 15 carbon atoms with from about 3 to about 9 carbon atoms in the carbon-to-carbon chain, said alkyl, phenyl or alkylene being unsubstituted or substituted by halogen, cyano or nitro or, in the case of phenyl, lower alkyl. Further, R.sup.2, or both R.sup.1 and R.sup.2 may represent hydrogen.
While sodium perborate tetrahydrate will normally be used, both in terms of economy and convenience, other alkali metal perborates may be employed of the formula (III)
MBO.sub.3.nH.sub.2 O (III)
wherein M is an alkali metal, preferably sodium or potassium, and n is 1 to 4, usually 4. Suitably, the oxidation is carried out with the perborate (III) in the presence of an acid that hydrolyzes in water to form hydronium ions, such as mineral acids, sulfonic acids, organic acids, and the like, but a Lowry-Bronsted acid or Lewis acid may also be used, such as BF.sub.3. Glacial acetic acid is safe and economical and hence is presently preferred. Other useful organic acids include trifluoroacetic acid and formic acid.
When an organic acid is employed, it may also serve as a solvent. If a solvent or co-solvent is required, any suitable inert solvent may be employed, such as acetone, halogenated hydrocarbons, such as methylene chloride, chloroform and the like, aliphatic and aromatic esters, benzene and the like. It is noted that acetone, while a ketone, is nevertheless not oxidized by the perborate (III) and hence may be used as a solvent, if desired.
Usually, the oxidation will be initiated at a temperature of from about 30.degree. to about 70.degree. C., usually from about 40 to about 60.degree. C. While lower temperatures can be used, reaction rates will necessarily be slower. Temperatures higher than about 70.degree. C. may be used, if required or desired, depending upon the desired reaction rate. However, the reaction is exothermic and hence external cooling may be needed to control the reaction temperature, even at the lower temperatures employed.
The present invention is illustrated in terms of its preferred embodiments in the following Examples. In this specification and the appended claims, all parts and percentages are by weight, unless otherwise stated.
EXAMPLE 1
Preparation Of Epsilon-Caprolactone
To a 200 ml roundbottom flask was added 4.9 grams (0.05 mole) of cyclohexanone, 50ml of glacial acetic acid, and 11.4 grams (0.075 mole) of sodium perborate tetrahydrate. The mixture was heated to 50.degree. C. using a water bath. The reaction temperature was maintained in the range of 50-55.degree. C., while stirring the mixture with a magnetic stirrer for four hours, after which the reaction mixture was cooled to room temperature, and the solid sodium borate was separated from the mixture using section filtration. The acetic acid was stripped from the remaining liquid residue using a rotary evaporator, and the remaining epsilon-caprolactone was purified by vacuum distillation. Yield: 91% theoretical.
EXAMPLE 2
Preparation of Benzoic Acid
The procedure of Example 1 was followed using 5.3 grams (0.05 mole) of benzaldehyde as the starting material. Crude benzoic acid formed was purified by recrystallization. Yield: about 50% theoretical.
EXAMPLES 3-6
Following the procedure of Example 1, the ketones set forth below were oxidized with sodium perborate at a temperature of about 55.degree. C. to provide the esters and acid set forth in Table 1 below.
TABLE 1
______________________________________
Example
Starting Material
End Product Yield
______________________________________
##STR3##
##STR4## 75%
4
##STR5##
##STR6## 74%
5
##STR7##
##STR8## 68%
6
##STR9##
##STR10## 24%
HOOC(CH.sub.2).sub.5COOH
38%
The most current patent detailing this reaction process, which has links to the relevant patent history of the prior art, is as follows:
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/search-bool.html&r=2&f=G&l=50&co1=AND&d=ptxt&s1=%27sodium+perborate%27&s2=Baeyer-Villiger&OS=%22sodium+perborate%22+AND+Baeyer-Villiger&RS=%22sodium+perborate%22+AND+Baeyer-Villiger (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/search-bool.html&r=2&f=G&l=50&co1=AND&d=ptxt&s1=%27sodium+perborate%27&s2=Baeyer-Villiger&OS=%22sodium+perborate%22+AND+Baeyer-Villiger&RS=%22sodium+perborate%22+AND+Baeyer-Villiger)
Post 531053 (https://www.thevespiary.org/talk/index.php?topic=7530.msg53105300#msg53105300)
(psychokitty: "Propenylbenzenes anyone?", Chemistry Discourse):(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_imgs/pdf.gif)
doi:10.1038/35086670 (http://dx.doi.org/doi%3A10.1038/35086670)
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