Synthesis of hexanal

Preparation of hexanal

Alternative Names: caproaldehyde; hexaldehyde; caproic aldehyde; capronaldehyde;

Preparation of hexanal from 1-bromopentane and ethyl orthoformate

Preparation of hexanal from 1-bromopentane and ethyl orthoformate

Preparation of hexanal from 1-bromopentane and ethyl orthoformate

A 1-liter three-necked flask, fitted with a dropping funnel, an air tight stirrer and an efficient condenser with calcium chloride tube. 15 g of dry magnesium turnings, 25 ml of anhydrous ether and a small crystal of iodine are placed in the reaction flask, followed by 2.5 ml (3 g) of dry 1-bromopentane. As soon as the reaction commences 100 ml of anhydrous ether are added, followed by a solution of 76 ml (91.5 g) of dry 1-bromopentane in 100 ml of anhydrous ether at such a rate that the ether refluxes steadily. The addition takes about 20 minutes and if the reaction becomes too vigorous, cooling in ice water may be necessary. When all 1-bromopentane has been added the obtained solution is refluxed for 30 minutes in order to complete the reaction. The mixture is cooled to room temperature and then to about 5° C, and 83 ml (74 g) of ethyl orthoformate are dropwise added  during about 10 minutes. The mixture is refluxed for 6 hours and when the reaction is complete, ether is removed by evaporation. The obtained residue is treated with 375 ml of ice-cold 6% hydrochloric acid while stirring and keeping the contents of the flask cool by the occasional addition of a little crushed ice. When all the white inorganic material has passed into solution, the organic layer is transferred to a separatory funnel. The upper layer of n-hexaldehyde diacetal is removed and hydrolyzed by distilling with a solution of 27.5 ml (50 g) of concentrated sulfuric acid in 350 ml of water. The obtained hexanal is collected in a solution containing 50 g of sodium bisulfite in 150 ml of water. The oily layer of distillate, which is largely 1-pentanol is removed, as it is insoluble in the sodium bisulfite solution. The obtained bisulfite solution is steam distilled until 100 ml of the distillate have been collected in order to completely separate the remainder of the amyl alcohol and other impurities. The residual bisulfite solution is cooled to about 45° C, then a suspension of 40 g of sodium bicarbonate in 100 ml of water are cautiously added and the resulting free hexanal is separated by steam distillation. The upper layer containing crude hexanal is removed, washed with three 25 ml portions of water, and dried with anhydrous sodium or magnesium sulfate. The hexanal is purified by distillation through a short column and collect the fraction boiling at 127-129° C. The yield of hexanal is 25 g.

A text book of practical organic chemistry, by A. I. Vogel, 323-324, 1974

Preparation of hexanal from n-amyl cyanide (1-pentyl cyanide) by Stephen Reaction

Preparation of hexanal from n-amyl cyanide (1-pentyl cyanide) by Stephen Reaction

Preparation of hexanal from n-amyl cyanide (1-pentyl cyanide) by Stephen Reaction

Into a 500 ml, three-necked flask, provided with a mechanical stirrer, a gas inlet tube and a reflux condenser, 57 g of anhydrous tin(II) chloride and 200 ml of anhydrous ether are placed. Dry hydrogen chloride gas is passed in until the mixture is saturated and separates into two layers, where the lower viscous layer consists of tin(II) dichloride dissolved in ethereal hydrogen chloride. 19.5 g of n-amyl cyanide are added while stirring through the separatory funnel and the separation of the crystalline aldimine hydrochloride commences after a few minutes, meanwhile, the stirring is continued for 15 minutes. The crystalline solid is filtered, suspended in about 50 ml of water and heated under reflux until it is completely hydrolyzed. The cold solution is extracted with ether, dried with anhydrous magnesium or calcium sulfate and the ether is slowly removed by evaporation. Finally, the residue is purified by distillation collecting fraction boiling at 127-129° C. The yield of hexanal is 19 g.

A text book of practical organic chemistry, by A. I. Vogel, 324, 1974





InChI Key


Canonical SMILES


MeSH Synonyms

(E)-2-hexanal, (Z)-hex-3-enal, caproic aldehyde, capronaldehyde, E-2-hexanal, hexanal, hexanaldehyde, n-hexanal

Depositor-Supplied Synonyms

HEXANAL, Caproaldehyde, Hexaldehyde, Caproic aldehyde, Capronaldehyde, 66-25-1, n-Hexanal, Hexanaldehyde, 1-Hexanal, n-Caproaldehyde, Aldehyde C-6, Hexylaldehyde, Hexyl aldehyde, n-Caproylaldehyde, n-Hexaldehyde, n-Capronaldehyde, Kapronaldehyd, Hexoic aldehyde, C6 aldehyde, n-Caproic aldehyde, Hexanal (natural), Kapronaldehyd [Czech], FEMA Number 2557, NSC 2596, UNII-9DC2K31JJQ, FEMA No. 2557, CCRIS 3219, CHEMBL280331, HSDB 560, Aldehyde C6, JARKCYVAAOWBJS-UHFFFAOYSA-N, EINECS 200-624-5, UN1207, BRN 0506198, AI3-15364, DSSTox_CID_1604, DSSTox_RID_76231, DSSTox_GSID_21604, CAS-66-25-1, E-2-hexanal, n-Hexylaldehyde, 1-hexanone, Aldehydes, C6, hexan-1-al, PubChem3077, AC1Q2VPQ, ACMC-1BFR4, n-C5H11CHO, AC1L1LZ0, WLN: VH5, 9DC2K31JJQ, SCHEMBL22263, n-HEXALDEHYDE, 98%, KSC353M9N, W255718_ALDRICH, W255726_ALDRICH, W255734_ALDRICH, 115606_ALDRICH, C6H12O, 21520_FLUKA, CTK2F3696, HMDB05994, NSC2596, MolPort-001-769-760, NSC-2596, Tox21_201933, Tox21_303342, 7134AH, ANW-35172, BDBM50028824, LMFA06000109, STL280331, ZINC01641021, AKOS009156478, EBD3061058, LS-2339, NE10466, RP18712, RTR-022440, UN 1207, TRA-0203532, NCGC00249137-01, NCGC00257270-01, NCGC00259482-01, AN-23753, CJ-05867, CJ-26448, Hexaldehyde [UN1207] [Flammable liquid], DB-054893, TR-022440, FT-0631290, FT-0669191, Hexaldehyde [UN1207] [Flammable liquid], EN300-33498, 4-01-00-03296 (Beilstein Handbook Reference), A835388, S14-1025, 3B3-030019

Removed Synonyms

(E)-2-hexanal, (Z)-Hex-3-enal, CID6184, H0133, C010463, 1219803-74-3

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