(Hive Addict)
12-17-03 19:20
No 477426
(Rated as: excellent)
This method of oxidizing phenylpropenes to their corresponding benzaldehydes has been mentioned before in the following posts:
Post 317548 (3base: "vanillin from 3-methoxy-4-hydroxy-propenylbenzene", Chemistry Discourse)
Post 317565 (3base: "isoeugenole --> vanillin", Chemistry Discourse)
Post 317876 (3base: "isosafrole --> piperonal (V2O5, yield 67.4%)", Chemistry Discourse)
Post 317882 (3base: "Re: What is "the peroxide reagent"?", Chemistry Discourse)
A Synthesis of N-(3-Methoxybenzyl)-N-methyl-3-methoxy-4
K. E. Hamlin, Arthur W. Weston
J. Am. Chem. Soc. 71, 2210-2212 (1949) (../rhodium/pdf /3-meo-45-mdp
(Retrieved by Rhodium. Thanks!)
From p. 2210:
Myristicinaldehyde.
Fractionation of heavy oil of nutmeg obtained from Fritzsche Brothers, Inc., yielded 7.5% myristicin, b. p. 118-120°C (2 mm.), n25D 1.5385. This was rearranged to isomyristicin with ethanolic potassium hydroxide in 89% yield; b. p. 110-115°C (1 mm.); m. p. 42-44' (lit.9 44°C). The method of Milas7 for the oxidation of isoeugenol and anethole by means of hydrogen peroxide and vanadium pentoxide was applied to isomyristicin. In this manner, myristicinaldehyde, m. p. 130-131°C , was obtained in an average yield of 51%.
(7) Milas, this journal, 69, 2342 (1937)
(9) Power and Salway, J. Chem. Soc., 91, 2055 (1907).
The Hydroxylation of Unsaturated Substances. III. The Use of Vanadium Pentoxide and Chromium Trioxide as Catalysts of Hydroxylation
Nicholas A. Milas J. Am. Chem. Soc. 59, 2342-2344 (1937) (../rhodium/pdf /v2o5.propeny
Also retrieved by Rhodium in the abovementioned post.
The Hydroxylation of Unsaturated Substances.
The Use of Vanadium Pentoxide and Chromium Trioxide as Catalysts of Hydroxylation
by Nicholas A. Milas
The catalytic hydroxylation of unsaturated substances has been under way in this Laboratory for some time. Of particular usefulness has been the method recently described1 and extended to embrace a great number of substances.2 In this method hydrogen peroxide in anhydrous tertiary butyl or tertiary amyl alcohols and in the presence of osmium tetroxide adds onto carbon-carbon double bonds to form glycols. Although the mechanism of this reaction has not been entirely elucidated, evidence has been accumulated to indicate that it proceeds through the formation of perosmic acid which probably dissociates into hydroxyl radicals and osmium tetroxide. In this way the catalyst seems to act, like ultraviolet light,3 as though it dissociates the hydrogen peroxide into hydroxyl radicals which subsequently add onto double bonds or cause other oxidations. Like osmium there are a number of metals belonging to the IV, V and VI sub-groups bf the Periodic System which are known to form very unstable peracids rather than peroxides. These metals include Ti, Zr, Th, V, Nb, Ta, Cr, Mo, W and U.
A study of the behavior of the oxides of these metals on hydroxylation has been undertaken during the past year and some preliminary results are now available with vanadium pentoxide and chromium trioxide. Table I summarizes some of the results obtained.
TABLE I
SUMMARY OY RESULTS
| Substance | Main product | Yield% with V2O5 | Yield% with CrO3 |
| Trimethylethylene | Trimethylethylene glycol | 36.4 37.3 | 16.8 |
| Diethyl fumarate | Diethyl racemate | 57 | .. |
| Anethole | Anisaldehyde | 55 | 13.7 |
| Isoeugenol | Vanillin | 66 | 58.3 |
| Isosafrole | Piperonal | 67.5 | 14.0 |
| Benzene | Phenol | 30 | 12.2 |
In addition to the substances mentioned in the foregoing table, cyclohexene yielded a small amount of cis-cyclohexanediol-1,2, an unidentified aldehyde and considerable quantities of adipic acid. Cresols were obtained from toluene and naphthols from naphthalene. These reactions and their mechanism are being actively investigated at present and will be reported elsewhere.
Experimental
The Catalysts.
(1) Vanadium Pentoxide.
This catalyst may be obtained from the Vanadium Corporation of America or it may be prepared in accordance with the method described elsewhere.6 Vanadium pentoxide is almost entirely insoluble in tertiary butyl or tertiary amyl alcohol but, when the latter contains hydrogen peroxide, it goes promptly into solution to form blood red pervanadic acid6. The reaction mixture, as a rule, remains blood red until the end of the reaction when either the vanadium pentoxide precipitates out as a dark brown solid, or remains in solution as blue or green lower oxide. In every case the catalyst may be rejuvenated easily by the addition of more peroxide reagent.
(2) Chromium Trioxide.
Unlike vanadium pentoxide, this catalyst is soluble in both tertiary butyl and tertiary amyl alcohols yielding brownish-red solutions. However, when hydrogen peroxide is present these solutions are deep blue. This color is due to the formation of the unstable perchromic acid.7 The catalytic reactions with chromium trioxide are, as a rule, more vigorous but less efficient in the production of the desired product than reactions with other catalysts. At the end of each reaction the blue color disappears and goes over into a transitory purple color and finally a bluish-green precipitate comes down which has the properties of chromic oxide. When the reaction has reached this stage, the catalyst cannot be rejuvenated by the addition of peroxide reagent.
Trimethylethylene Glycol from Trimethylethylene.
Fourteen grams of trimethylethylene (b. p. 38.3-38.4°C) was mixed with an equimolecular quantity of the peroxide reagent1 and to the mixture was added 0.03 g. of vanadium pentoxide. The catalyst dissolved in a few minutes and the solution warmed up considerably. It was then cooled under running water for twenty-four hours when the reaction appeared complete. The mixture was filtered and the filtrate fractionally distilled through a Davis column to remove the solvent and the unused trimethylethylene (5 g.), When the residue was fractionated under reduced pressure, a fraction (5 g.) was obtained which boiled at 80-83°C (13 mm.). The b. p. of trimethylethylene glycol is given in the literature as 80-82°C (13 mm.)8 and 85-87°C (15 mm).9 The yield of this glycol, calculated on the basis of the trimethylethylene used, amounted to 37.3%. Another experiment, repeated in exactly the same way as the above, yielded 36.4% of trimethylethylene glycol. The experiment was again repeated using the same quantities of trimethylethylene and the peroxide reagent but, instead of vanadium pentoxide, 0.02 g. of pure chromium trioxide was used. The solution warmed up and had to be cooled under running water. At the end of twenty-four hours the reaction was over and the catalyst had precipitated out as a bluish-green solid. When the mixture was fractionated, 8 g. of unused trimethylethylene and 1.5 g. of the glycol were obtained in addition to some acetic acid.
Racemic Acid from Diethyl Racemate.
To 17.2 g. of diethyl fumarate (Eastman Kodak Company) were added 66 cc. of the peroxide reagent and 0.02 g. of vanadium pentoxide. After the catalyst went into solution, the mixture warmed up considerably and had to be cooled under running water. At the end of twenty-four hours the solution had turned greenish-blue and the reaction was complete. The solvent was then removed under reduced pressure and the ester saponified in 10% alcoholic potash. When the alcohol was distilled and the residue acidified with dilute hydrochloric acid, 3 g. of unreacted fumaric acid was recovered. The filtrate yielded 11 g. of calcium racemate precipitated in ammoniacal solution.1 This corresponds to a yield of 57% of the diethyl fumarate used.
Anisaldehyde from Anethole.
To 5 g. of anethole (Eastman Kodak Company) were added 45 cc. of the peroxide reagent and 0.02 g. of vanadium pentoxide. The catalyst went slowly into solution, which heated up almost to the b. p. of the solvent. The reaction was over in about two hours when the mixture became deep red and the peroxide had completely disappeared. Considerable amounts of acetaldehyde vapor came off during the reaction. The solvent was then removed under reduced pressure and the residue dissolved in glacial acetic acid. Aliquot parts of this were analyzed for anisaldehyde by precipitating the latter as the p-nitrophenylhydrazone in accordance with the method described elsewhere.l0 The yield of anisaldehyde amounted to 55%. A small amount of the p-nitrophenylhydrazone was recrystallized twice from glacial acetic acid; m. p. 159-160°C. Ciusa and Vecchiottill give 160°C as the m. p. of this phenylhydrazone. In addition to anisaldehyde some anisic acid was isolated from the reaction, and a small amount of a deep red solid which is presumably an addition product of vanadium pentoxide with anisaldehyde.12 Another experiment was performed in which the catalyst was 0.02 g. of chromium trioxide. The solution heated up within a short time to almost the b. p. of the solvent. After about one hour the reaction was over when the mixture became deep brown and a small amount of the chromic oxide separated out. As before, the mixture was analyzed for anisaldehyde and found to have only 13.7% of it.
Piperonal from Isosafrole.
Five grams of isosafrole (Eastman Kodak Company) was mixed with 45 cc. of the peroxide reagent and to the mixture was added 0.02 g. of vanadium pentoxide. As the catalyst dissolved, the mixture heated up as before to almost the b. p. of the solvent. The reaction was over in about two hours when the mixture was still blood red due perhaps to the presence of the addition complex between vanadium pentoxide and piperonal.12 The yield (67.4%) of piperonal, in this case, was also estimated by precipitating its p-nitrophenylhydrazone.10 This p-nitrophenylhydrazone was recrystallized twice from 95% ethyl alcohol, m. p. 202-203°C. An authentic sample prepared and purified in the same way had a m. p. of 203-203.5°C; mixed m. p. showed no depression. In another experiment in which 0.02 g. of chromium trioxide was used as the catalyst, the yield of piperonal was only 14%.
Vanillin from Isoeugenol.
Five grams of isoeugenol (Eastman Kodak Company) was mixed with 45 cc. of the peroxide reagent and 0.02 g. of vanadium pentoxide. As in the case of the experiments with the other two essential oils, the catalyst went into solution, which heated up but not as much as in the two previous rases. The reaction was complete in about twelve hours when the mixture had become more intensely red.12 An analysis for the presence of vanillin by precipitating the p-nitrophenylhydrazone10 gave a yield of 66% of vanillin. The above experiment was then repeated using 0.02 g. of chromium trioxide as the catalyst. When the product was worked up, a yield of 58.3% of vanillin was obtained.
Phenol from Benzene.
Fifteen and six-tenths grams of benzene (thiophene-free) was mixed with an equimolecular quantity of the peroxide reagent and 0.04 g. of vanadium pentoxide. The catalyst went slowly into solution which, after a few hours, acquired a blood red color. At the end of twenty-four hours, the reaction was complete, the red color had disappeared and the catalyst separated out as a dark green precipitate. The mixture was then filtered, the filtrate fractionated to remove the solvent and unused henzene (13 g.), the residue dissolved in water, and the amount of phenol estimated by precipitating the insoluble tribromophenol. Two and nine-tenths grams of tribromo- phenol was obtained corresponding to 30% yield of phenol calculated on the basis of the amount of benzene used. A sample of tribromophenol was recrystallized from dilute alcohol, m. p. 93°C, and showed no depression upon mixing with an authentic sample of tribromophenol. When the foregoing experiment was repeated using 0.04 g. of chromium trioxide as the catalyst, only 12.1% of phenol was obtained in spite of the fact that a larger amount (4.1 g.) of benzene was utilized. In addition to phenol, the residue from this experiment contained a dark solid which failed to dissolve in water, but was soluble in dilute alkali showing that it was probably a polyphenol. This was separated before the estimation of phenol was made in the sample.
The author wishes to acknowledge the assistance of Mr. Alva C. Sapp in the analytical work.
Summary
1. Hydrogen peroxide in anhydrous tertiary butyl alcohol and in the presence of vanadium pentoxide or chromium trioxide effects the oxidation (hydroxylation) of a number of unsaturated substances.
2. Trimethylethylene glycol was obtained from trimethylethylene ; diethyl racemate from diethyl fumarate; anisaldehyde and anisic acid from anethole; piperonal from isosafrole ; vanillin from isoeugenol; and phenol from benzene. In all of the cases described, the catalytic reactions seem to proceed through the intermediate formation of the unstable peracids of the catalysts used; e. g., pervanadic and perchromic acids.
Cambridge, Mass. Recieved august 30, 1937
References
(1) Milas and Sussman, this journal, 58, 1302 (1936). *
(2) Milas and Sussman, ibid., 69, 2545 (1937); also unpublished results.
(3) Milas, Kurz and Anslow, Jr., ibid., 69, 543 (1937).
(4) Riesenfeld, Ber., 41, 3536 (1908) ; Machu, "Wasserstoffperoxyd und die Perverbindungen." Verlag von Julius Springer, Wien, 1937, p. 240.
(5) Milas, this journal, 49, 2006 (1927).
(6) Meyer and Pawletta, Z. Angew. Chem., 89, 1284 (1926); Rumpf, Compt. rend., 200, 317 (1935).
(7) Moissan, ibid., 97, 96 (1883); Bancroft and Murphy, J. Phys. Chem., 89, 377 (1935).
(8) Ciamician and Silber, Ber., 44, 1283 (1911).
(9) Boeseken. Rec. trav. chim., 45, 556 (192C)(<- it is like this in the paper).
(10) Milas, this journal, 62, 744 (1930).
(11) Ciusa and Vecchiotti, Gazz. chim. ital., 42, I, 632 (1912).
(12) Tunmann and Rosenthaler, Pflanzenmikrochemie 334 (1931).
(*): We need to dig this one up too, for the preparation of the peroxide reagent.
EDIT: Thanks Lugh!
The Other War (http://www.markfiore.com/animation/drug
(Moderator)
12-17-03 19:32
No 477429
(Rated as: good read)
Here's the requested procedure and articles by Milas, JACS 58, 1302 (1936); 58, 2345 (1937); 59, 543 (1937); 61, 1844 (1939); 62, 1844 (1940) & 81, 3115 (1958):
Experimental
Preparation of the Reagent.-To 100 cc. of 30% hydrogen peroxide (Albone C) was added 400 cc. of pure tertiary butyl alcohol and the solution treated with small portions of anhydrous sodium sulfate whereby two layers separated out. The alcohol layer, which contained most of the hydrogen peroxide, was removed and dried with anhydrous sodium sulfate and finally with anhydrous calcium sulfate (Drierite). A solution of 6.32% hydrogen peroxide in tertiary butyl alcohol was obtained, giving a recovery of 93.8%. This solution can easily be concentrated by vacuum distillation of the alcohol at room temperature to any desired concentration without any loss of the peroxide provided an all-glass apparatus is employed. When hydrogen peroxide solutions of this sort were allowed to stand at room temperature for over six months only a small decrease in hydrogen peroxide concentration was noticed.
Chemistry is our Covalent Bond
(Stranger)
12-17-03 19:58
No 477435
(Rated as: good read)
He also patented his invention.
Patent US2402566 - NA Milas. Hydroxylation of unsaturated carboxylic acid compounds and the like. (1946)
[...]
Vanillin from isoeugenol - Five grams of isoeugenol was mixed with 45 cc of 6.3% solution of hydrogen peroxide in anhydrous tertiary amyl alcohol and 0.02 g of vanadium pentoxide. The catalyst went into solution, which heated up spontaneously. The reaction was completed in about twelve hours when the mixture had become more intensely red. An analysis for the presence of vanillin by precipitating the p-nitrophenylhydrazone gave a yield of 66% of vanillin.
Anisaldehyde from anethole - To 5 g of anethole were added 45 cc of 6.3% solution of hydrogen peroxide in anhydrous tertiary amyl alcohol and 0.02 g of vanadium pentoxide. The catalyst went slowly into solution, which heated up almost to the boiling point of the solvent. The reaction was over in about two hours when the mixture became deep red and the peroxide had completely disappeared. Considerable amounts of acetaldehyde vapor came off during the reaction. The solvent was then removed under reduced pressure and the residue dissolved in glacial acetic acid. Aliquot parts of this were analyzed for anisaldehyde. The yield of anisaldehyde amounted to 55%. In addition to anisaldehyde some anisic acid was isolated from the reaction, and a small amount of a deep red solid which is presumably an addition product of vanadium pentoxide with anisaldehyde.
[...]
President of the Iraqi Chemical Weapons of Mass Destruction Development Society
(Moderator)
01-06-04 10:27
No 480716
(Rated as: good read)
Another article on hydroxylation:
Catalytic Hydrogen Peroxide Oxidation of
Aromatic Hydrocarbons
J. W. Cook and R. Schoental
J. Chem. Soc. 1950, 47
Chemistry is our Covalent Bond