Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1997-01-23
1998-09-22
Geist, Gary
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
568764, 568771, C07C 4536
Patent
active
058115870
DESCRIPTION:
BRIEF SUMMARY
This is the US National Stage Application of PCT/FR96/00778 filed May 24, 1996 now WO96/37452 published Nov. 28, 1996.
The present invention concerns a process for the hydroxyalkylation of a carbocyclic aromatic ether.
The invention preferably relates to the preparation of 3-methoxy-4-hydroxybenzyl alcohol, known as "p-vanillol", by the hydroxymethylation of guaiacol.
It also concerns the oxidation of the hydroxyalkylated ethers obtained, in particular the oxidation of 3-methoxy-4-hydroxybenzyl alcohol to 3-methoxy-4-hydroxybenzaldehyde, commonly known as "vanillin".
European patent EP-A-0 485 613 describes the para-hydroxymethylation of a phenol, in particular guaiacol, by reacting the latter with formaldehyde in an alcoholic organic solvent and in the presence of a quaternary ammonium compound such as tetramethylammonium hydroxide.
In addition to having to work in an anhydrous alcoholic medium, the major disadvantage of that process is the use of a quaternary ammonium compound which must be recovered at the end of the reaction as it is expensive.
The present invention provides a novel process which uses a heterogeneous catalyst which can overcome the above disadvantages.
We have now discovered, and this forms an object of the present invention, a process for the hydroxyalkylation of a carbocyclic aromatic ether which consists of reacting the aromatic ether with a carbonyl compound in the presence of a catalyst, characterized in that the hydroxyalkylation reaction is carried out in the presence of an effective quantity of a zeolite.
The invention concerns carbocyclic aromatic ethers.
In the following disclosure of the invention, the term "carbocyclic aromatic ether" denotes an aromatic carbocycle in which one hydrogen atoms which is directly bonded to the aromatic nucleus is replaced by an ether group, and the term "aromatic" denotes the conventional concept of aromaticity as defined in the literature, in particular by Jerry MARCH, Advanced Organic Chemistry, 4th edition, John Wiley and Sons, 1992, pp. 40 ff.
More precisely, an object of the present invention is to provide a process for the hydroxyalkylation of a carbocyclic aromatic ether with general formula (I): ##STR1## where: A represents the residue of a cycle forming all or a portion of a monocyclic or polycyclic aromatic carbocyclic system containing at least one OR' group: the cyclic residue may carry one or more substituents; may be a saturated or unsaturated, linear or branched acyclic aliphatic radical; a monocyclic or polycyclic, and saturated, unsaturated or aromatic cycloaliphatic radical; or a saturated or unsaturated, linear or branched aliphatic radical carrying a cyclic substituent;
For simplicity in the present text, the term "alkoxy groups" denotes --O--R' type groups where R' has the meaning given above. R' thus represents both a saturated, unsaturated or aromatic, acyclic or cycloaliphatic aliphatic radical and a saturated or unsaturated aliphatic radical carrying a cyclic substituent.
The carbocyclic aromatic ether used in the process of the invention has formula (I) where R' represents a saturated or unsaturated, linear or branched acyclic aliphatic radical.
More preferably, R' represents a linear or branched alkyl radical containing 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms: the hydrocarbon chain may be interrupted by a heteroatom (for example oxygen), by a functional group (for example --CO--) and/or may carry a substituent (for example a halogen).
The saturated or unsaturated, linear or branched acyclic aliphatic radical may carry a cyclic substituent. The term cycle preferably denotes a saturated, unsaturated or aromatic carbocyclic cycle, preferably cycloaliphatic or aromatic, and in particular cycloaliphatic containing 6 carbon atoms in the cycle, or benzenic.
The acyclic aliphatic radical may be bonded to the cycle by a valence bond, a heteroatom or a functional group; examples are given above.
The cycle may optionally be substituted; examples of cyclic substituents are substituents such as R whose meaning is des
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Fajula Francois
Finiels Annie
Gilbert Laurent
Moreau Claude
Razigade-Trousselier Sylvie
Carleton Katherine L.
Geist Gary
Padmanabhan Sreeni
Rhone-Poulenc Chimie
Seugnet Jean-Louis
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