Process for the separation of formic acid from methyltetrahydrofuran

Abstract

The invention relates to a process to separate formic acid from methyltetrahydrofuran (MTHF) said process comprising subjecting a composition comprising formic acid and MTHF to distillation, characterized in that the process comprises adding water to said distillation. This allows for cost-efficient recovery and recycling of MTHF, for example in process to produce and recover formic acid from a biomass hydrolysate.

Claims

1. A process for separating formic acid from methyltetrahydrofuran, comprising: subjecting a composition comprising formic acid and methyltetrahydrofuran to distillation, wherein the composition comprises a formic acid-methyltetrahydrofuran azeotrope; adding water to the distillation in an amount sufficient to form a water-methyltetrahydrofuran azeotrope and a water-formic acid azeotrope; recovering methyltetrahydrofuran as a distillate; and recovering formic acid as a distillation residue, wherein the recovered formic acid is in the form of a water-formic acid azeotrope.

2. The process according to claim 1, wherein the amount of water added to the distillation is at least 14 wt % to 60 wt %, based on a total weight of the composition.

3. The process according to claim 1, wherein the amount of water added to the distillation is at least 6 wt % based on a total weight of the composition.

4. The process according to claim 1, wherein the water is added by reflux.

5. The process according to claim 1, wherein the recovered methyltetrahydrofuran is in the form of a water-methyltetrahydrofuran azeotrope.

6. The process according to claim 5, further comprising isolating the methyltetrahydrofuran from the water-methyltetrahydrofuran azeotrope.

7. The process according to claim 1, further comprising isolating the formic acid from the water-formic acid azeotrope.

8. The process according to claim 1, wherein the composition comprises an organic phase obtained by extraction.

9. The process according to claim 8, wherein the extraction comprises contacting methyltetrahydrofuran with a biomass hydrolysate.

10. The process according to claim 1, wherein the composition is a distillate.

11. The process according to claim 1, further comprising feeding the recovered methyltetrahydrofuran to an extraction.

12. A process for separating formic acid from methyltetrahydrofuran, comprising: distilling a composition comprising formic acid, methyltetrahydrofuran, and a formic acid-methyltetrahydrofuran azeotrope; adding water during distillation of the composition in an amount sufficient to form a water-methyltetrahydrofuran azeotrope and a water-formic acid azeotrope; recovering formic acid as a distillation residue in the form of a recovered formic acid is in the form of a water-formic acid azeotrope; and isolating the formic acid from the water-formic acid azeotrope.

13. The process according to claim 12, wherein the amount of water added during distillation of the composition is at least 6 wt % to 60 wt %, based on a total weight of the composition.

14. The process according to claim 12, wherein the amount of water added to the distillation is at least 14 wt % to 60 wt %, based on a total weight of the composition.

15. The process according to claim 12, wherein the composition further comprises levulinic acid, humins, or a mixture thereof.

16. A process for separating formic acid from methyltetrahydrofuran, comprising: distilling a composition comprising formic acid, methyltetrahydrofuran, and a formic acid-methyltetrahydrofuran azeotrope; adding water during distillation of the composition in an amount sufficient to form a water-methyltetrahydrofuran azeotrope and a water-formic acid azeotrope; recovering methyltetrahydrofuran as a distillate in the form of a water-methyltetrahydrofuran azeotrope; and recovering formic acid as a distillation residue in the form of a water-formic acid azeotrope.

17. The process of claim 16, further comprising: isolating the methyltetrahydrofuran from the water methyltetrahydrofuran azeotrope; and isolating the formic acid from the water-formic acid azeotrope.

Description

EXAMPLES

Example 1

(1) A solution (total weight: 204.71 g) containing 51.5% formic acid, 34.3% MTHF and 14.2% water was subjected to split column batch distillation at atmospheric pressure. During the distillation 12 fractions were isolated and analysed whereby fraction 12 represents the distillation residue. Table 1 shows the composition of the fractions and the representative weight of the total intake of the mixture.

(2) TABLE-US-00001 TABLE 1 Distillation results amount formic acid MTHF water fraction (g) (wt %) (wt %) (wt %) 1-6 72.1 <0.01 93.3 9.7 7 2.63 7 82.8 12.5 8 5.14 78.7 20.9 1.2 9 10.10 90.3 8.9 0.8 10 14.51 87.7 0.77 11.5 11 7.46 83.0 <0.01 17.0 12 91.00 77.5 <0.01 22.5 mass 202.93 recovered

(3) The mass balance is at least 99% which indicates that there are no losses of material during the distillation and no by product formation.

(4) From this data it is evident that the distillation can be conducted in a continuous manner yielding formic acid essentially free of MTHF and an MTHF fraction essentially free of formic acid.

Example 2

(5) A solution (total weight: 200.8 g) containing 57.0% formic acid, 38.0% MTHF and 5.0% water was subjected to split column batch distillation at atmospheric pressure. During the distillation in total 18 fractions were isolated and analysed whereby fraction 18 represents the distillation residue. Table 2 shows the composition of the fractions and the representative weight of the total intake of the solution.

(6) TABLE-US-00002 TABLE 2 Distillation results amount formic acid MTHF water fraction (g) (wt %) (wt %) (wt %) 1-4 27.84 0.004 89.3 10.6 5-9 13.17 0.028 89.3 10.6 10-11 10.77 47.8 50.6 4.6 12-13 50.70 45.6 42.1 2.3 14-15 44.85 70.3 28.5 1.2 16 19.77 91.3 8.1 0.6 17 7.21 86.2 0.7 13.1 18 22.49 79.2 0.02 20.6 mass 196.80 recovered

(7) The mass balance is at least 98% which indicates that there are no losses of material during the distillation and no by product formation.

Example 3

(8) A solution containing 60% formic acid and 40% MTHF is subjected to split column batch distillation at atmospheric pressure. Distillation fractions and the residue are isolated and analysed. The mass balance indicates that are no losses of material during the distillation and no by product formation. However, the MTHF and formic acid cannot be separated from each other. A formic acid-MTHF azeotrope is demonstrated at 80 C. and 0.5 bar.