Process for the preparation of a furfural derivative
A furfural derivative having the chemical formula (1) wherein R represents hydrogen, an alkyl group or an acyl group, is prepared in a process, which process includes reacting a fructose- and/or glucose-containing starting material with a liquid hydroxyl group-containing compound of formula R—OH in the presence of an acid catalyst at a reaction temperature in the range of 150 to 300° C. to produce an acid reaction mixture including the furfural derivative of chemical formula (1), which acid reaction mixture has a pH-value of smaller than 3; neutralizing the acid reaction mixture to a pH-value in the range of 3 to 6.5 to provide a partially neutralized reaction mixture; and purifying the partially neutralized reaction mixture to recover the furfural derivative of chemical formula (1).
1. A process for the preparation of a furfural derivative having the chemical formula (1)
wherein R represents hydrogen, an alkyl group or an acyl group, which process comprises:
reacting a fructose- and/or glucose-containing starting material with a liquid hydroxyl group-containing compound of formula R—OH in the presence of an acid catalyst at a reaction temperature in the range of 150 to 300 ° C. to produce an acid reaction mixture comprising the furfural derivative of chemical formula (1), which acid reaction mixture has a pH-value of smaller than 3;
neutralizing the acid reaction mixture to a pH-value in the range of 3 to 6.5 to provide a partially neutralized reaction mixture; and
purifying the partially neutralized reaction mixture to recover the furfural derivative of chemical formula (1),
wherein, if R represents an acyl group, the acyl group is derived from a carboxylic acid that is selected from C 1 -C 6 carboxylic acids, and
wherein the acid reaction mixture has a pH of smaller than 2.
2. The process according to claim 1 , wherein the liquid hydroxyl group-containing compound is water or methanol or a mixture thereof.
3. The process according to claim 1 , wherein the acid catalyst is a Bronsted acid selected from the group consisting of mineral inorganic acids, organic acids and mixtures thereof.
4. The process according to claim 1 , wherein the acid reaction mixture is neutralized by the addition of an alkali metal or alkaline earth metal hydroxide or alkoxide.
5. The process according to claim 1 , wherein the acid reaction mixture is subjected to a separation step before being neutralized wherein part of the liquid hydroxyl group-containing compound is separated from the acid reaction mixture.
6. The process according to claim 5 , wherein the partially neutralized reaction mixture is subjected to separation of at least part of the liquid hydroxyl group-containing compound from the partially neutralized reaction mixture to yield a product mixture; and to recovery of the furfural derivative with the chemical formula (1) from the product mixture.
7. The process according to claim 6 , wherein the partially neutralized reaction mixture is subjected to evaporation to yield the product mixture.
8. The process according to claim 1 , wherein the furfural derivative with the chemical formula (1) is recovered by evaporation or distillation to yield the furfural derivative with the chemical formula (1) and a bottom residue comprising acid catalyst.
9. The process according to claim 8 , wherein the bottom residue is washed with an aqueous liquid.
10. The process according to claim 1 , wherein the acid reaction mixture is neutralized at a temperature in the range of 25 to 150 ° C. and a pressure of 0.1 to 40 bar.