Process for the preparation of a furfural derivative comprising neutralizing an acid reaction mixture
A furfural derivative having the chemical formula (1) where 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 a primary acid reaction mixture including the furfural derivative of chemical formula (1); separating part of the liquid hydroxyl group-containing compound from the primary acid reaction mixture to yield a secondary acid reaction mixture; neutralizing the secondary acid reaction mixture to a pH-value of at least 3 to obtain a neutralized reaction mixture; and purifying the 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 a primary acid reaction mixture comprising the furfural derivative of chemical formula (1);
separating at least part of the liquid hydroxyl group-containing compound from the primary acid reaction mixture to yield a secondary acid reaction mixture;
neutralizing the secondary acid reaction mixture to a pH-value of at least 3 to obtain a neutralized reaction mixture; and
purifying the 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 C1-C6 carboxylic acids.
2. The process according to claim 1 , wherein R represents an alkyl group.
3. The process according to claim 1 , wherein the liquid hydroxyl group-containing compound is water or methanol or a mixture thereof.
4. The process according to claim 1 , wherein the acid catalyst is a Brønsted acid selected from the group consisting of mineral inorganic acids, organic acids and mixtures thereof.
5. The process according to claim 1 , wherein the secondary acid reaction mixture has a pH of smaller than 2.
6. The process according to claim 1 , wherein the secondary acid reaction mixture is neutralized by the addition of an alkali metal or alkaline earth metal hydroxide or alkoxide.
7. The process according to claim 1 , wherein the neutralized reaction mixture is subjected to separation of at least part of the liquid hydroxyl group-containing compound from the neutralized reaction mixture to yield a product mixture; and to recovery of the furfural derivative with the chemical formula (1) from the product mixture.
8. The process according to claim 7 , wherein the neutralized reaction mixture is subjected to evaporation to yield the product mixture.
9. 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.
10. The process according to claim 9 , wherein the bottom residue is washed with an aqueous liquid.
11. The process according to claim 1 , wherein the secondary 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.