Preparation of cyclohexanemethanol (cyclohexylcarbinol; cyclohexanecarbinol)
1-liter three-necked flask is fitted with air tight stirrer, a 500 ml dropping funnel and a reflux condenser to the upper end of which a drying tube with anhydrous calcium chloride is attached. All parts of the glass apparatus must be dry. The flask is partially immersed in a bath of water and charged with 26.7 grams of magnesium turnings (the turnings are prepared by washing with a little absolute ether to remove surface grease, drying at 100-120° C, and allowing to cool in a desiccator) and a crystal of iodine in the flask. Separately in a dry vessel 121 ml (or 118.5 grams) of cyclohexyl chloride and 450 ml of absolute ether are mixed and introduced about 100 ml of the ether and 15 ml of the cyclohexyl chloride into the reaction flask. The water bath is slowly heated so that the ether refluxes gently in order to start the reaction. When the reaction has commenced the water bath is removed and sufficient amount of absolute ether is introduced with constant stirring to cover the magnesium. Then the remainder amount of the cyclohexyl chloride dissolved in the residual ether is introduced during 30-45 minutes. If the reaction becomes too vigorous, the flask is cooled in ice water. When all cyclohexyl chloride has been added the refluxing and stirring is continued for 15-20 minutes in order to complete the formation of the Grignard reagent.
The separatory funnel is replaced by a wide rubber tube fitted over the neck of the flask and attached to the small conical flask charged with 50 grams of paraformaldehyde, which has been previously dried in a vacuum desiccator over phosphorus pentoxide. The mixture is stirred vigorously and gradually the paraformaldehyde is added by suitably inclining the conical flask. After 2 hours, the reaction mixture is transferred to a 2-liter bolt-head flask and treated with 300 grams of finely crushed ice all at once while vigorously agitating the mixture until the decomposition is complete. A double amount of theoretical quantity of 30% sulfuric acid is added in order to dissolve the magnesium hydroxide, and the reaction solution is steam distilled until no more oil passes over (2000-2500 ml). The distillate is saturated with sodium chloride and separated the upper ether layer, which is dried with anhydrous potassium carbonate and the ether is removed by evaporation. 5 grams of freshly dehydrated calcium oxide are added and heated on a water bath for 30 minutes in order to remove the last traces of water and forming a halogen-free cyclohexanemethanol. The solution is filtered washed with a little amount of anhydrous ether. The ether is removed and the residue is distilled under diminished pressure. The fraction boiling at 88-93° C/18 mm is collected yielding 50 grams of cyclohexanemethanol. The boiling point of cyclohexanemethanol at atmospheric pressure is 182°C.
An improved yield of cyclohexanemethanol (75 grams) may be obtained by substituting gaseous formaldehyde for paraformaldehyde. The gaseous formaldehyde is obtained by placing 50 grams of paraformaldehyde, previously dried for few days over phosphorus pentoxide, in a 500 ml round-bottomed flask provided with an inlet tube for admitting dry nitrogen. The flask is heated in an oil bath at 180-200° C, and the formaldehyde vapour is carried into the Grignard reagent by a slow stream of nitrogen through a wide glass tube fitted into the neck of the flask. The entry tube should terminate about 1 cm above the surface of the solution; clogging, due to re-polymerized formaldehyde is thus largely avoided.
By using di-n-butyl ether as solvent, paraformaldehyde may be employed instead of gaseous formaldehyde without appreciable influence upon the yield. The high boiling point (141° C) of n-butyl ether obviates the necessity of depolymerising the paraformaldehyde as a separate operation. The Grignard reagent is prepared with n-butyl ether as solvent using the proportions of reagents given above. The solution is heated to 100-110° C in an oil bath, and 100 grams of dry paraformaldehyde is added in small portions to the well-stirred solution over 2 hours. The product is isolated as above; 70 grams of cyclohexanemethanol with boiling point 88-93° C/18 mm., are obtained.
Org. Synth. 1926, 6, 22
A text book of practical organic chemistry, by A. I. Vogel, 252-253, 1974
CYCLOHEXANEMETHANOL, Cyclohexylmethanol, 100-49-2, Cyclohexylcarbinol, Hexahydrobenzyl alcohol, Cyclohexanecarbinol, Methanol, cyclohexyl-, Cyclohexylmethyl alcohol, (Hydroxymethyl)cyclohexane, Benzyl alcohol, hexahydro-, USAF DO-49, Cyclohexyl methanol, CyclohexYl-Methanol, Hydroxymethylcyclohexane, NSC 5288, VSSAZBXXNIABDN-UHFFFAOYSA-N, EINECS 202-857-8, SBB061328, cyclohexylmethan-1-ol, BRN 0773712, AI3-01172, cyclohexane-methanol, PubChem3098, hydroxymethyl-cyclohexane, ACMC-1BSUF, 4-cyclohexylmethylalcohol, 1-hydroxymethylcyclohexane, CYCLOHEXYL CARBINOL, (hydroxymethyl)-cyclohexane, AC1L1OX1, AC1Q7C8Z, WLN: L6TJ A1Q, UNII-4VDR6634UG, SCHEMBL20903, C105805_ALDRICH, 4VDR6634UG, AC1Q7C90, 55640_FLUKA, VSSAZBXXNIABDN-UHFFFAOYSA-, NSC5288, MolPort-001-779-796, ACT10090, NSC-5288, ANW-14298, AR-1I3166, GEO-00862, ZINC01680819, AKOS000249005, MCULE-6571547092, NE10104, RP19156, TRA0041536, TRA0084492, AJ-29641, AK-47687, CJ-06285, CJ-27629, KB-49212, LS-56891, M217, SC-00039, TS-01583, DB-016119, RT-000229, AM20070443, FT-0624189, ST24030281, ST51047352, EN300-21580, A15048, 65174-EP2269977A2, 65174-EP2277861A1, 65174-EP2298742A1, 65174-EP2308812A2, 4-06-00-00106 (Beilstein Handbook Reference), I14-0566, T7019302, 3B3-003508, InChI=1/C7H14O/c8-6-7-4-2-1-3-5-7/h7-8H,1-6H2, Cyclohexylmethane;cyclohexyl-methano;Cyclohexylmethyl alcohol;hexahydro-benzylalcohol