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US 5,489,731 AGranted
Preparation of aromatic vinyl compounds
AssigneeBASF SE
InventorKlaus Ditrich
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AssigneeBASF SE
InventorKlaus Ditrich
Estimating the term…
Aromatic vinyl compounds of the formula I Ar--CH.dbd.CHR I where Ar is an aromatic radical, and R is hydrogen, C.sub.1 -C.sub.4 -alkyl or unsubstituted or substituted phenyl, are prepared by reacting an alcohol of the formula II Ar--CH.sub.2 OH II or an ester of the formula III ##STR1## where R' is hydrogen or C.sub.1 -C.sub.4 -alkyl, in aqueous solution with a triarylphosphine and a strong acid and then, in the presence of a mineral base, with an aldehyde of the formula IV R--CHO IV.
A two-step process for preparing aromatic vinyl compounds of the formula I
Dependencies are inferred from the claim text.
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Preparation of halogenated hydrocarbons: by reactions not affecting the number of carbon or of halogen atoms in the reaction
Reactions without formation or introduction of functional groups containing hetero atoms, involving
Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts: substituted by unsaturated carbon radicals
By reactions involving an increase in the number of carbon atoms in the skeleton: by condensation reactions
Term ended 1 Dec 2013 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to a novel process for preparing aromatic vinyl compounds of the formula I
Ar--CH.dbd.CHR I
where Ar is an aromatic radical, and R is hydrogen, C.sub.1 -C.sub.4 -alkyl or unsubstituted or substituted phenyl.
1.5 mol of 37% strength aqueous acid were added to a mixture of 1 mol of alcohol II and 1.05 mol of triphenylphosphine. The mixture was heated at 85.degree. C. for 2 hours, and 500 ml (6.6 mol) of 37% strength aqueous formaldehyde solution and 425 ml (8.0 mol) of 50% strength sodium hydroxide solution were added. The solution was maintained at 60.degree. C. for 3 hours. After filtration, the product was isolated by extraction with n-hexane and was distilled.
______________________________________ Substituents on the benzyl Example alcohol Acid Yield [%] ______________________________________ 1 4-OCH.sub.3 HBr 95 2 2-I HBr 70 3 3-Cl, 4-Cl HBr 94 4 4-Cl HCl 100 5 3-OMe, 4-OMe HBr 40 6 3-OMe, 4-OMe, 5-OMe HBr 75 7 2-OMe, 3-OMe HBr 86 8 4-COOH HCl 68 ______________________________________
1 mol of benzyl ester III was reacted as in Examples 1-8.