Synthesis of 1-heptene

Preparation of 1-heptene

Preparation of 1-heptene from n-butyl magnesium bromide and allyl bromide

Preparation of 1-heptene from n-butyl magnesium bromide and allyl bromide

Preparation of 1-heptene from n-butyl magnesium bromide and allyl bromide

All the reagents and the apparatus must be perfectly dry. n-Butyl magnesium bromide (the Grignard reagent) is prepared from 12.2 grams of dry magnesium turnings, a small crystal of iodine, 54 ml (or 69 grams) of n-butyl bromide and 260 ml of anhydrous ethyl ether.  12.2 grams of dry magnesium turnings, a small crystal of iodine, and 170 ml of sodium-dried ethyl ether are added in the three-neck reaction flasks. 54 ml (or 69 grams) of n-butyl bromide and 90 ml of anhydrous ether are mixed. The obtained solution is placed in the separatory funnel, which is protected with a calcium chloride tube. 10-15 ml of the n-butyl bromide solution are dropwise added to the reaction flask while stirring. The reaction soon commences and, within a few minutes, the refluxing is vigorous. When this occurs, the flask is cooled by immersing an ice-water mixture, and the additional portion of the n-butyl bromide solution is added at such a rate that moderate refluxing occurs. When all the n-butyl bromide solution has been added the cooling bath is removed and stirring is continued for a further 15 minutes. n-Butyl magnesium bromide is prepared yielding only a small remaining residue of magnesium. A 500 ml three-necked flask is fitted with an air tight stirrer, a 100 ml separatory funnel and a double surface condenser. The solution of prepared n-butyl magnesium bromide solution is forced with the aid of pure, dry nitrogen and a tube containing a plug of purified glass wool into the 500 ml flask through the top of the double surface condenser. Solid magnesium must be absent to avoid the formation of diallyl via allyl magnesium bromide; the insertion of a short plug of glass wool effectively removes any finely divided magnesium. The separatory funnel is charged with a solution of 35 ml (or 50 grams) of allyl bromide dissolved in 25 ml of anhydrous ether, protected with the calcium chloride drying tubes into the top of the double surface condenser and of the dropping funnel. The flask containing the n-butyl magnesium bromide solution is immersed in cold water, and the allyl bromide is added while stirring at such a rate that the ether boils gently. If the reaction becomes too vigorous the reaction flask is cooled momentarily in ice cold water. It is important that the allyl bromide reacts when added, as indicated by gentle boiling of the solution. If reaction does not occur when a little allyl bromide is first introduced, further addition must be discontinued until the reaction has commenced. When all the allyl bromide has been introduced, the stirring is continued for 45 minutes whilst refluxing gently by immersion of the flask in a bath of warm water. Then the flask is cooled and the content of the flask is poured cautiously on to the excess of crushed ice contained in a large beaker. The solid magnesium complex is decomposed with ice and dilute sulfuric acid or concentrated ammonium sulfate solution. The ether layer is separated, washed with ammoniacal ammonium sulfate solution in order to remove any dissolved magnesium salts, and dried over anhydrous magnesium sulfate. 1-Heptene is distilled and after the ether has passed over, the fraction boiling at 93-95° C is collected yielding 29 grams of 1-heptene.

A text book of practical organic chemistry, by A. I. Vogel, 240, 1974

IUPAC Name

hept-1-ene

InChI

InChI=1S/C7H14/c1-3-5-7-6-4-2/h3H,1,4-7H2,2H3

InChI Key

ZGEGCLOFRBLKSE-UHFFFAOYSA-N

Canonical SMILES

CCCCCC=C

Depositor-Supplied Synonyms

1-HEPTENE, Hept-1-ene, HEPTENE, 592-76-7, Heptylene, n-Hept-1-ene, 1-n-Heptene, NSC 74130, HSDB 1078, ZGEGCLOFRBLKSE-UHFFFAOYSA-N, EINECS 209-767-8, SBB059882, UN2278, 25339-56-4, n-Heptene, .alpha.-Heptylene, Heptene (petroleum), AC1Q2VPB, AC1L1XQ9, H3208_ALDRICH, 442267U_SUPELCO, UNII-O748KJ11V7, Heptene (mixed cis and trans), 262269_ALDRICH, ACMC-1B032, 51856_FLUKA, CTK1H3107, MolPort-001-756-619, O748KJ11V7, NSC74130, STR07011, EINECS 246-871-2, EINECS 271-209-4, ANW-42069, LMFA11000319, NSC-74130, ZINC01699515, AKOS009031489, 1-C7H14, MCULE-5868303078, NE10660, RP18656, RTR-020568, TRA0077952, AN-17739, AN-21549, CJ-28600, LS-74578, n-Heptene [UN2278] [Flammable liquid], DB-053357, n-Heptene [UN2278] [Flammable liquid], TR-020568, FT-0632465, S0337, ST51046147, 79604-EP2270113A1, 79604-EP2272935A1, 79604-EP2295418A1, 79604-EP2305696A2, 79604-EP2305698A2, I14-19270, 3B3-023408

Removed Synonyms

Alkenes, C6-8, C7-rich, CID11610, H0042, 68526-53-4

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