Cyclohexanol preparation

Let s begin with a simple example Suppose you wanted to prepare cyclohexane given cyclohexanol as the starting material We haven t encountered any reactions so far that permit us to carry out this conversion m a single step... 

Recognizing that cyclohexene may be prepared by dehydration of cyclohexanol a prac tical synthesis of cyclohexane from cyclohexanol becomes apparent... 

Methanethiol (eq. 6) and cyclohexanethiol (eq. 7) are the only commercially important thiols prepared using alcohol substitution. In most cases, when the alcohol is utilized, less control over the substitution patterns is obtained. Only one isomer is obtainable in the case of methanol and cyclohexanol. 

Cyclohexanol [108-93-0] is a colorless, viscous liquid with a camphoraceous odor. It is used chiefly as a chemical iatermediate, a stabilizer, and a homogenizer for various soap detergent emulsions, and as a solvent for lacquers and varnishes. Cyclohexanol was first prepared by the treatment of 4-iodocyclohexanol with ziac dust ia glacial acetic acid, and later by the catalytic hydrogenation of phenol at elevated temperatures and pressures. 

Cyclohexanone [108-94-17 is a colorless, mobile Hquid with an odor suggestive of peppermint and acetone. Cyclohexanone is used chiefly as a chemical iatermediate and as a solvent for resias, lacquers, dyes, and iasecticides. Cyclohexanone was first prepared by the dry distillation of calcium pimelate [19455-79-9] OOC(CH2 )5COO Ca , and later by Bouveault by the catalytic dehydrogenation of cyclohexanol. 

Me3SiCH2CH=CH2i TsOH, CH3CN, 70-80°, 1-2 h, 90-95% yield. This silylating reagent is stable to moisture. Allylsilanes can be used to protect alcohols, phenols, and carboxylic acids there is no reaction with thiophenol except when CF3S03H is used as a catalyst. The method is also applicable to the formation of r-butyldimethylsilyl derivatives the silyl ether of cyclohexanol was prepared in 95% yield from allyl-/-butyldi-methylsilane. Iodine, bromine, trimethylsilyl bromide, and trimethylsilyl iodide have also been used as catalysts. Nafion-H has been shown to be an effective catalyst. 

Cyclohexene can be prepared on a large scale still more rapidly and efficiently by the distillation of cyclohexanol over silica geP or, better, activated alumina. Using a 25-mm. tube packed with 8- to 14-mesh activated alumina (Aluminum Company of America) and heated to 380-450 over a 30-cm. length, 1683 g. of cyclohexanol was dehydrated in about four hours. After separating the water, drying with sodium sulfate, and fractionating with a simple column, 1222 g. (89 per cent yield) of cyclohexene, b.p. 82-84 , was obtained. 

Monodispersed poly (methyl methacrylate-ethyleneglycol dimethacrylate) is prepared by a multistep swelling and polymerization method. When a good solvent such as toluene is applied as a porogen, the seed polymer severely affects the pore structure, whereas no effects are observed with poor solvents, such as cyclohexanol, as a porogen, in comparison with the conventional suspension polymerization (68,69). 

Preparation from hcxamethyldisiloxane and 12/AI powder in detail, followed by cleavage of cyclohexyl methyl ether, to give cyclohexanol (via the intermediate silyl ether). 

Finally, reaction of primary, secondary, or tertiary alcohols 11 with Me3SiCl 14 in the presence of equivalent amounts of DMSO leads via 789 and 790 to the chloro compounds 791 [13]. n-Pentanol, benzyl alcohol, yS-phenylefhanol or tert-butanol are readily converted, after 10 min reaction time, into their chloro compounds, in 89-95% yield, yet cyclohexanol affords after reflux for 4 h cyclohexyl chloride 784 in only 6% yield [13] (Scheme 6.5). 1,4-Butanediol is cyclized to tetrahydrofuran (THF) [13a], whereas other primary alcohols are converted in 90-95% yield into formaldehyde acetals on heating with TCS 14 and DMSO in benzene [13b] (cf also the preparation of formaldehyde di(n-butyl)acetal 1280 in Section 8.2.1). 

You are the Production Manager for a plant producing adipic acid by the nitric acid oxidation of a mixture of cyclohexanone and cyclohexanol. Your company is preparing for ISO 14001 registration. 

When nitric acid was added to cyclohexanol when preparing cyclohexane-1,2-dione, the reactor detonated, probably because of the exothermicity of the oxidation reaction, which was complete instead of partial (reaction (2)). 

In a 1500 ml. round-bottomed flask, carrying a reflux condenser, place 100 g. of pure cyclohexanol, 260 ml. of concentrated hydrochloric acid and 80 g. of anhydrous calcium chloride heat the mixtiure on a boiling water bath for 10 hours with occasional shaking (1). Some hydrogen chloride is evolved, consequently the preparation should be conducted in the fume cupboard. Separate the upper layer from the cold reaction product, wash it successively with saturated salt solution, saturated sodium bicarbonate solution, saturated salt solution, and dry the crude cj/clohexyl chloride with excess of anhydrous calcium chloride for at least 24 hours. Distil from a 150 ml. Claisen flask with fractionating side arm, and collect the pure product at 141 5-142-5°. The yield is 90 g. 

An alternative method of conducting the preparation consists in treating 100 g. of cyclohexanol with 260 ml. of concentrate hydrochloric acid, refluxing slowly whiM a stream of hydrogen chloride gas is passed into the mechanically stirred... 

General Methods. Methanol used in kinetic runs was distilled from sodium methoxide or calcium hydride in a nitrogen atmosphere before use. Freshly distilled cyclohexanol was added to the methanol in the ratio 6.0 ml cyclohexanol/200 ml MeOH and was used as an internal standard for gas chromatographic (GC) analysis. Benzaldehyde was distilled under vacuum and stored under nitrogen at 5°. Other aldehydes (purchased from Aldrich) were also distilled before use. The corresponding alcohols (purchased from Aldrich) were distilled and used to prepare GC standards. All metal carbonyl cluster complexes were purchased from Strem Chemical Company and used as received. Tetrahydrofuran (THF) was distilled from sodium benzophenone under nitrogen before use. 

Esters of phosphorofluoridic acid. Two procedures for the preparation of the esters of phosphorofluoridic acid were developed, a general one applicable to most alcohols and a special one for cyclohexanol. 

This technology was extended to the preparation of chiral capillary columns [ 138 -141 ]. For example, enantioselective columns were prepared using a simple copolymerization of mixtures of O-[2-(methacryloyloxy)ethylcarbamoyl]-10,11-dihydro quinidine, ethylene dimethacrylate, and 2-hydroxyethyl methacrylate in the presence of mixture of cyclohexanol and 1-dodecanol as porogenic solvents. The porous properties of the monolithic columns can easily be controlled through changes in the composition of this binary solvent. Very high column efficiencies of 250,000 plates/m and good selectivities were achieved for the separations of numerous enantiomers [140]. 

HIGHLY REACTIVE CALCIUM FOR THE PREPARATION OF ORGANOCALCIUM REAGENTS PREPARATION OF 1-ADAMANTYL CALCIUM HALIDES AND THEIR ADDITION TO KETONES 1-(1-ADAMANTYL)CYCLOHEXANOL (Cyclohexanol, 1 -trlcyclo[3.3.1.13>7]dec-1-yl)... 

Distillation can be used to purify a compound by separating it from less volatile substances in a reaction mixture. You may have used this technique to prepare cyclohexene from cyclohexanol. In this reaction, cyclohexanol is mixed with concentrated phosphoric acid and an elimination reaction takes place. 

In preparing cyclohexene from cyclohexanol, the impure cyclohexene obtained during the distillation of the reaction mixture can be further purified by solvent extraction. This can be done by adding the crude cyclohexene to a separating funnel along with an equal volume of sodium chloride solution. Impurities in the cyclohexene are extracted into the lower aqueous sodium chloride layer. The cyclohexene layer is then run off and treated with anhydrous magnesium sulfate to remove any remaining water. 

Pankova and Tichy prepared all four stereoisomeric 4-rerr-butyl-2-aminomethyl-l-cyclohexanols and cyclized them with ethyl benzimidate to hexahydro-l,3-benzoxazines 158-161 (74CCC1447). From the A-acyl O-mesylate derivatives 162 and 163 on thermal cyclization or thionyl chloride treatment, ring closure occurred with inversion and resulted in 158 and 159 (74CCC1447). 

In the reactions of cis- and rrans-2-aminomethyl-l-cyclohexanol or -1-cycloheptanol or cis- and trans-2-hydroxymethyl-l-cyclohexylamine or -1-cycloheptylamine with ethyl 4-chlorobenzimidate, the stereo- and regio-isomeric derivatives and homologs 164 and 165 were prepared (79T799). The amidine intermediate 166 of the benzimidate ring closure was also... 

An early illustration of this ambiguous behavior was provided by Letsinger and coworkers in 1952 who wanted to prepare alkyl cyclohexanols by addition of n-butyllithium to cyclohexene oxide. Only 7% of the desired butyl cyclohexanol 4 was... 

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