demorol
(Hive Bee)
12-29-02 03:20
No 393789
      Oxidation of alcohols
(Rated as: excellent)
    

Oxidation of Alcohols by Ca(OCl)2-Al2O3, Bull. Korean Chem. Soc., 1988, Vol. 9, No. 1, pp 60

Typical procedure

In a typical oxidation, to a stirred solution of an alcohol (0.6 mmol) in benzene (10mL) was added a grounded solid mixture of calcium hypochlorite (0.68g, 2.4 mmol) and basic alumina (0.68g) at room temperature. The mixture was stirred further at room temperature. The reaction mixture was filtered and the solvent was evaporated to afford the crude product. The yield was determined by GLC.

Benzyl alcohol -> Benzaldehyde, 99%, reaction time: 4h;
o-Chlorobenzyl alcohol -> o-Chlorobenzaldehyde, 95%, reaction time:7 h:
p-Chlorobenzyl alcohol -> p-Chlorobenzaldehyde, 96%, reaction time: 6 h;
Benzhydrol -> Benzophenone, 100%, reaction time: 3 h;
Cyclohexanol -> Cyclohexanone, 15%, reaction time: 8 h.

The given yields are yields determined by GLC. Isolated yields would be somewhat lower.


Oxidation of Alcohols with NiO2-Al2O3, Bull. Korean Chem. Soc., 1991, Vol. 12, No. 2, pp 115

The oxidation was performed by stirring the benzene solution (10mL) of an alcohol (1 mmol) with the solid mixture of nickel peroxide (0.46g, 1.50 mmol) and Al2O3 (W-200-B) (0.46g) at room temperature under nitrogen. After completiotion of the reaction, the solid was removed by the filtration and evaporation of the solvent afforded the product.

Benzyl alcohol -> Benzaldehyde, 98%, time: 3 h;
sec-phenethyl alcohol -> Acetophenone, 97%, time: 3 h;
p-Anisyl alcohol -> p-Anisaldehyde, (85%), time: 5 h;
Benzhydrol -> Benzophenone, (95%), time: 2 h;
Allyl alcohol -> Acrolein, 98%, time: 3 h;
3-Buten-2-ol -> 3-Buten-2-one, 98%, time: 2 h;
Crotyl alcohol -> Crotonaldehyde, 99%, time: 3 h;
Cinnamyl alcohol -> Cinnamaldehyde, 98%, time: 3 h;
Geraniol -> Geranial, 85%, time: 6 h.

Yields in parentheses are isolated yields. All other yields are yields determined by GC.


Environmentally-Friendly TEMPO-Mediated Oxidation of Alcohols with Poly[4-(diacetoxyiodo)styrene], Synthesis, 2003, No. 1, pp 21-23

Abstract: Primary and secondary alcohols were successfully oxidized to the corresponding aldehydes and ketones in good yields, respectively, with poly[4-(diacetoxyiodo)styrene] (PSDIB) in the presence of TEMPO (cat.) in acetone, as environment-friendly method.

Poly[4-(diacetoxyiodo)styrene]

A mixture of polystyrene (Aldrich Co. No. 33165-1, average M.W. ca. 200 000 and 4 000, 16g, 153 mmol), I2 (18g, 71 mmol), I2O5 (7g, 21 mmol), CCl4 (40mL), and 50% H2SO4 (35mL) in nitrobenzene (200mL) was kept at 90 C for 72 h. The reaction mixture was then diluted with CHCl3 (100mL) and precipitated by the addition of MeOH (1500mL). The precipitates were collected by filtration to give poly(4-iodostyrene). 30% H2O2 (40mL) was added dropwise to Ac2O (145mL) at 0 C. The solution was slowly warmed to room temperature and stirred overnight. To this solution was added poly(4-iodostyrene) (8g) and the solution was kept at 50 C overnight. Et2O was then added to the solution for precipitation and the product (ca. 9g) was collected by filtration.

Oxidation of Alcohols with Poly[4-(diacetoxyiodo)styrene] (PSDIB); General Procedure

PSDIB (0.6g, 1.2 mmol) was added to a solution of the appropriate alcohol (1 mmol) and TEMPO (0.031g, 0.2 mmol) in acetone (2mL) and the mixture was stirred at room temperature for the time given below. At end of reaction, Et2O (10mL) was added and the reaction mixture was filtered to remove the polymer. After removal of the solvent from the filtrate, the corresponding carbonyl compound was obtained in over 95% purity. If necessary, the filtrate was poured into H2O and extracted with Et2O (3 10mL). The combined organic extracts were dried over Na2SO4, filtered and the solvent was removed in vacuo. The residue was chromatographed on silica gel to give the pure carbonyl compound. The polymer reagent can be regenerated by treating poly(4-iodostyrene) with peracetic acid to give PSDIB and reused for the same reaction.

Benzyl alcohol -> Benzaldehyde, 90%, time: 2 h;
p-Methylbenzyl alcohol -> p-Methylbenzaldehyde, 93%, time: 2 h;
1-Phenyl-1-propanol -> 1-Phenyl-1-propanone, 94%, time: 6 h.


Oxidation of Alcohols to Carbonyl Compounds using Chromic Anhydride-Chlorotrimethylsilane-Alumina, Bull. Korean Chem. Soc., 1989, Vol. 10, No. 5, pp 471

Typical procedure

Chromic anhydride (10g, 100 mmol) and chlorotrimethylsilane (21g, 200 mmol) were added to carbon tetrachloride (150mL). The mixture was stirred for 30 minutes or until a dark red solution was obtained. Basic alumina (50g, 500 mmol) was added. To the stirred heterogenous solution was slowly added 1-hexanol (7.6g, 75 mmol) as a solution in a small amount of carbon tetrachloride. After 2 hours of vigorous stirring, the whole reaction mixture was filtered through a short column of silica gel. The clear filtrate was concentrated on a rotary evaporator. Distillation of the crude product using a short-path distilling apparatus or Kugelrohr afforded 6.8g (83%) of pure hexanal (bp 129-131 C)

This oxidation can be carried out on a 1-30g scale without any problems or major modification of the procedure.

Benzyl alcohol -> Benzaldehyde, 90%, time: 30 min;
p-Methoxybenzyl alcohol -> p-Methoxybenzaldehyde, 94%, time: 1 h;
p-Nitrobenzyl alcohol -> p-Nitrobenzaldehyde, 88%, time: 1 h;

I'm dreaming of the white crystals.
 
 
 
 
    alphacentauri
(Hive Bee)
12-31-02 14:39
No 394576
      Could be used the concentrated industrial...     

Could be used the concentrated industrial solution of NaClO instead of tha Ca compound? That is to say, since NaClO comes with water, just mixing hypochlorite solution with benzyl alcohol, adding Al2O3 and stirring 4 hours? Then removing the benzaldehyde as the bisulphite adduct?
 
 
 
 
    demorol
(Hive Bee)
01-01-03 09:06
No 394705
      Another article
(Rated as: excellent)
    

Applications of Ammonium Molybdate: Oxidation of Arylmethanols to Aromatic Aldehydes, Synthesis, 1985, No. 6/7, pp 652

Benzaldehyde; Typical Procedure:

A mixture of benzyl alcohol (5.4g), ammonium molybdate (40g), 6 M HCl (100mL), and dimethyl sulfoxide (25mL) is heated under reflux for 4 h. The deep-blue reaction mixture is cooled and extracted with 1:1 ether/benzene (3 25mL). the organic layer is successively washed with water, saturated solution of sodium hydrogen carbonate (it confirmed the abscence of carboxylic acid through acidification and usual work-up) and water, then dried with anhydrous sodium sulfate, and the solvent evaporated on a steam bath. Steam distillation from a Claisen flask with 2'' Vigreux column furnishes almost pure benzaldehyde; yield 3.8g (70%), bp 177-180 C; GLC indicates 93% purity.

The substituted arylmethanols are oxidized in a similar method with the molybdate (10g), 6 M HCl (40mL), and either dioxan or dimethyl sulfoxide (15-20mL), when aromatic aldehydes were obtained in yields randing from 45-70%, with the exception of p-methoxybenzaldehyde (25% yield).


I'm dreaming of the white crystals.
 
 
 
 
    demorol
(Hive Bee)
01-21-03 07:45
No 400189
      Oxidation using PCC & PVPCC
(Rated as: excellent)
    

Pyridinum Chlorochromate: A Versatile Oxidant in Organic Synthesis

Abstract: The first use of the title compound was for the oxidation of primary and secondary alcohols to carbonyl compounds. Subsequent increasing interest in this reagent has revealed its wide utility and versatility. The numerous applications of pyridinum chlorochromate in organic synthesis are now reviewed.

Preparation of PCC

Chromium trioxide (100g, 1 mol) is rapidly added with stirring to 6 M HCl (184mL, 1.1 mol). After 5 min the homogenous solution is cooled to 0 C and pyridine (79.1g, 1 mol) is carefully added over 10 min. Recooling to 0 C gives a yellow-orange solid which is collected on a sintered glass funnel and dried in vacuum for 1 h. Yield: 180.8g (84%)

Oxidation of Alcohols with PCC, General Procedure:

In a 500mL RB flask fitted with a reflux condenser, PCC (32.3g, 0.15 mol) is suspended in anhydrous CH2Cl2 (200mL). The alcohol (0.1 mol) in CH2Cl2 (20mL) is then added in one portion to the magnetically stirred suspension. After 1.5 h, dry diethyl ether (200mL) is added and the supernatant liquid is decanted from a black gum. The insoluble residue is washed with dry diethyl ether (3 50mL) and becomes a black granular solid. The combined organic solution is passed through a short pad of Florisil and the solvent is removed by distillation.

Preparation of Poly[vinyl(pyridinum Chlorochromate)]:

To cross-linked poly(vinylpyridine) resin (50-100 mesh; 10g) suspended in water (20mL) is added chromium trioxide (9g) and concentrated HCl (10mL). The mixture is stirred at room temperature for 1 h and filtered, the residue is washed with distilled water until the filtrate is clear. The freshly prepared product has a bright orange colour which turns to brown after drying in vacuum at 60 C for 5 h.

Oxidation of Alcohols with PVPCC; General Procedure:

To the resin from above, obtained by reaction of poly(vinylpyridine) (1g), dissolved in cyclohexane (4-10mL) is added the alcohol (1.7 mmol) and the mixture is stirred at 75-80 C. After 105 min the mixture is filtered and the resin washed with ether and CH2Cl2. The solvent is then evaporated to leave the carbonyl compound.

Cyclohexanol -> Cyclohexanone, PVPCC, 94%;
Benzyl alcohol -> Benzaldehyde, PVPCC, 95%.

Reference: Synthesis, 1982, No. 4, pp 245

I'm dreaming of the white crystals.
 
 
 
 
    demorol
05-20-03 04:59
      DMSO/acid oxidation of alcohols
(Rated as: redundant)
    
 
 
 
    Rhodium
(Chief Bee)
05-20-03 14:21
No 434396
      Link to old posts instead of duplicating, please.     

The entire article is already posted here: Post 382598 (GC_MS: "Benzyl Alcohols > Benzaldehydes (DMSO/Acid)", Methods Discourse) (and can be found at my page (../rhodium/chemistry /benzaldehydes.dmso.html).
 
 
 
 
    java
(Hive Bee)
11-24-03 10:05
No 472888
      RE: Demerol's Alcohol Reference's in pdf
(Rated as: good read)
    

These are the full articles to Demerol  references found in the Bu.. Korean Chem. Soc......perhaps they may be of some help....java


Oxidation of Alcohols by Ca(OCl)2-Al2O3
Kwan Soo Kim*, Yang Heon Song, and Chi Sun Hahn
Bull. Korean Chem. Soc., 1988, Vol. 9, No. 1, pp 60

http://journal.kcsnet.or.kr/publi/bul/bu88n1/60.pdf


Oxidation of Alcohols to Carbonyl Compounds using Chromic Anhydride-Chlorotrimethylsilane-Alumina
Jong-Gun Lee* and Dong Soo Ha
Bull. Korean Chem. Soc., 1989, Vol. 10, No. 5, pp 471

http://journal.kcsnet.or.kr/publi/bul/bu89n5/471.pdf


Oxidation of Alcohols with NiO2-Al2O3
Kwan Soo Kim*, Sung Bum Cho, and Chi Sun Hahn
Bull. Korean Chem. Soc., 1991, Vol. 12, No. 2, pp 115

http://journal.kcsnet.or.kr/publi/bul/bu91n2/115.pdf

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