Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
  • C07C41/01—Preparation of ethers
  • C07C41/18—Preparation of ethers by reactions not forming ether-oxygen bonds
  • C07C41/28—Preparation of ethers by reactions not forming ether-oxygen bonds from acetals, e.g. by dealcoholysis

Definitions

• the present invention relates to a process for the preparation of compounds of the formula I.
• R 1 and R 2 have the meanings given above, at temperatures between 50 ° C and 200 ° C to the submitted
• R 3 H, (C-j ⁇ -CG) alkyl which may be halogenated, (Cg-CgJCycloalkyl, phenyl which is mono- or polysubstituted by (C ⁇ -C ⁇ ) - may be substituted alkyl or halogen, or carboxy - (C * ⁇ - C 6 ) alkyl means, metered and the formed reaction products of formula I and formula IV
• R 2 has the abovementioned meaning, continuously distilled off from the reaction mixture.
• Alkyl means both straight-chain and branched alkyl.
• R ⁇ - preferably means isopropyl.
• Halogenated alkyl represents alkyl substituted one or more times, in particular by F, Cl or Br.
• the radicals trifluoromethyl, trichloromethyl and
• Tribromomethyl Tribromomethyl.
• alkylene oil ethers of the formula I are valuable
• the compounds of the formula I can be prepared by acid-catalyzed elimination of alcohol from the corresponding ketals of the formula II at elevated temperatures and then distilled off from the reaction mixture by conventional laboratory methods.
• acidic catalysts e.g. p-Toluenesulfonic acid, phosphoric acid, sulfuric acid, alkali hydrogen sulfate, boric acid and phosphoric acid pyridine or quinoline (Houben-Weyl, Methods of Organic Chemistry, Volume 6/3 p. 97; Kunz, Lindig, Chem. Ber. 116, 220-229
• the desired ⁇ l-enether can be produced in yields of> 97% of theory using the process according to the invention, the proportions of ⁇ 2-enol ether and polymeric residue each being ⁇ 1%.
• the process according to the invention is particularly easy to handle due to its continuous implementation.
• the process according to the invention is advantageously carried out in such a way that the ketals of the formula II are metered continuously into the heated carboxylic acid of the formula III and the resulting ⁇ l-enol ether of the formula I with the alcohol of the formula IV formed is distilled off continuously from the reaction mixture.
• the separation of the end products I from the alcohols IV is unproblematic and is carried out by distillation or extraction.
• reaction temperatures are between 50 ° C. and 200 ° C., preferably between 60 ° C. and 150 ° C.
• the ketal of formula II is either on the
• the process according to the invention is to be assessed as all the more surprising since the carboxylic acid of the formula III present in high excess at the time of the actual reaction does not undergo any reactions with the ⁇ 1-enol ethers formed.
• the polymerization products occurring in the known processes are not obtained here.
• Fe ner is known to have vinyl ether (enol ether)
• Carboxylic acids e.g. Acetic acid
• Carboxylic acids easily react to vinyl acetates or semi-acylals and thus yield reductions in products I can occur (. Reppe A, 601 (1956) 81-138; DF Schorstakowski and NA Ger ⁇ tein, J. allg. Chem. 21, 1452 (1951); Chem Zbl. 1952, 5395).
• distillate After a further 25 hours of distillation, a total of 569 g of distillate are obtained, which consists of 375 g of ⁇ l-enol ether, 55 g of ⁇ 2-enol ether and 139 g of methanol, which gives a yield of 75% of theory corresponds.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Cited By (2)

Citations (2)

• 1989
  • 1989-10-05 DE DE3933247A patent/DE3933247C1/de not_active Expired - Fee Related
• 1990
  • 1990-10-01 AU AU64429/90A patent/AU6442990A/en not_active Abandoned
  • 1990-10-01 WO PCT/EP1990/001646 patent/WO1991004956A1/de not_active Ceased
  • 1990-10-01 EP EP90914531A patent/EP0494906A1/de not_active Withdrawn
  • 1990-10-01 JP JP2513602A patent/JPH05500667A/ja active Pending
  • 1990-10-01 KR KR1019920700773A patent/KR950006801B1/ko not_active Expired - Lifetime
  • 1990-10-03 IL IL95896A patent/IL95896A0/xx unknown
  • 1990-10-04 ZA ZA907922A patent/ZA907922B/xx unknown
• 1992
  • 1992-04-03 HU HU9201136A patent/HUT61259A/hu unknown

Patent Citations (2)

Non-Patent Citations (2)

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