Method for producing alkoxy-hydroxybenzaldehyde that is substantially free of alkyl-alkoxy-hydroxybenzaldehyde
AssigneeRhodia Operations
InventorsLaurent Garel, Hubert Gayet
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Abstract
The invention relates to a method for producing at least one alkoxy-hydroxybenzaldehyde (AHBA) from at least one hydroxyphenol (HP), said method being characterized in that it comprises the formation of at least one alkoxyphenol (AP) and alkyl-alkoxyphenol (AAP) and the separation (S) of AP from AAP, said separation (S) being carried out prior to obtaining AHBA.
Claims17
A process for producing at least one alkoxyhydroxybenzaldehyde (“AHBA”), said process comprising forming at least one alkoxyphenol (“AP”) and at least one alkylalkoxyphenol (“AAP”) from at least one hydroxyphenol (“HP”) and separating (S) the AP from the AAP, said separating (S) being carried out prior to obtaining AHBA, wherein the AHBA is produced by addition of an aldehyde function to the AP by condensation with glyoxylic acid, followed by oxidation of the resulting compound, and wherein the separating (S) is carried out before the oxidation to give the AHBA compound.
A process for separating GA and/or GE from a mixture (M) comprising GA and/or GE and a 6-methylguaiacol (“MEGA”) and/or 6-ethylguaethol (“2-ethoxy-6-ethylphenol” or “EGE”) impurity, the process comprising introducing the mixture M into a distillation column in the presence of pyrocatechol (PC), recovering a stream or fraction comprising GA and/or GE at the top of the distillation column, and recovering a stream or fraction comprising PC, MEGA and/or EGE at the bottom of the distillation column.
A process for synthesizing at least one alkoxyphenol (“AP”) in the vapor phase, the process comprising forming at least one AP on the basis of an O-alkylation reaction in the vapor phase, between at least one hydroxyphenol (“HP”) and at least one O-alkylating agent, said reaction also forming at least one alkylalkoxyphenol impurity (“AAP”), said reaction thus forming a mixture M comprising AP, AAP and HP, introducing the mixture M into at least one distillation column, recovering a stream or fraction comprising AP at the top of the distillation column, recovering a stream or fraction comprising HP and AAP at the bottom of the distillation column, and optionally recycling the stream or fraction comprising AP downstream of the O-alkylation reaction and/or recycling the stream or fraction comprising HP upstream of the O-alkylation reaction.
Dependencies are inferred from the claim text.