PROCESS FOR PRODUCING ALKOXYLATED POLYPHENOLS

Abstract

The invention relates to a process for producing at least one alkoxylated polyphenol comprising the following successive steps: (a) reacting at least one polyphenol, at least one alkoxylating agent, at least one catalyst, in the presence of at least one poly (oxyalkylene glycol) as a solvent, at a temperature ranging from 80° C. to 200° C., preferably from 100° C. to 170° C., at a pressure ranging from 0.15 MPa to 2 MPa, preferably from 0.2 MPa to 1.8 MPa; then (b) removing the residual alkoxylating agent.

Claims

1. A process for producing at least one alkoxylated polyphenol comprising the following successive steps: (a) reacting at least one polyphenol, at least one alkoxylating agent, at least one catalyst, in the presence of at least one poly (oxyalkylene glycol) as a solvent, at a temperature ranging from 80° C. to 200° C., at a pressure ranging from 0.15 to 2 MPa; then (b) removing the residual alkoxylating agent.

2. The process according to claim 1, wherein said polyphenol is selected from natural tannins, lignins and polyphenols other than tannins and lignins.

3. Process according to claim 2, wherein said polyphenol is a lignin.

4. Process according to claim 1, wherein said alkoxylating agent has the following formula (I): ##STR00002## wherein R.sub.1 denotes a hydrogen atom or an alkyl radical in C.sub.1-C.sub.6.

5. A process according to claim 1, wherein said alkoxylating agent is selected from ethylene oxide, propylene oxide, butylene oxide, and mixtures thereof.

6. Process according to claim 1, wherein the polyphenol/alkoxylating agent weight ratio ranges from 0.05 to 2.

7. Process according to claim 1, wherein the catalyst is selected from alkali metal hydroxides, sodium or potassium alkoxides, and tertiary amines selected from trialkylamines and tetramethylguanidine, preferably selected from alkali metal hydroxides.

8. Process according to claim 1, wherein said poly (oxyalkylene glycol) is selected from polypropylene glycol, polybutylene glycol, alternating or random block copolymers obtained from the monomers, and mixtures thereof.

9. Process according to claim 1, wherein said poly (oxyalkylene glycol) is selected from dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polypropylene glycol 220, polypropylene glycol 400 and mixtures thereof.

10. Process according to claim 1, wherein the polyphenol/poly (oxyalkyleneglycol) weight ratio is less than or equal to 2.

11. Process according to claim 1, wherein it is carried out batchwise, semi-continuously or continuously.

12. Process according to claim 1, comprising a step (c) of recovering the alkoxylated polyphenol obtained after step (b).

13. An alkoxylated polyphenol obtainable by the process as defined in claim 1.

14. Use of poly (oxyalkylene glycol) as a solvent in a process for producing alkoxylated polyphenols.

15. Use of the alkoxylated polyphenol obtained by the process as defined in claim 1 for producing polyurethanes, polyesters, non-ionic or cationic surfactants, biosourced carbon fibre precursors.

Description

EXAMPLES

Example 1 (According to the Invention): Synthesis of Propoxylated Lignin in the Presence of PPG 220

[0084] 208.4 g of Indulin AT™ lignin, previously dried in an oven, in 479.3 g of polypropylene glycol 220 (PPG 220) and 8.3 g of finely ground caesium hydroxide are added into a 6 L autoclave. The weight ratio of lignin/PPG 220 is 43.5% by weight and the catalyst/lignin weight ratio is 4% by weight.

[0085] 3 purges are successively carried out with nitrogen. Leak tests are also carried out. The temperature is gradually increased with stirring of the reaction medium to 80° C. Nitrogen is re-pressurized to 0.25 MPa and then a 50 g fraction of propylene oxide is introduced. The temperature is gradually raised to a temperature of 120° C., at which temperature the attachment of the reaction can be observed.

[0086] The total propylene oxide, 488 g, is introduced at a temperature ranging from 120° C. to 130° C., at a maximum pressure of 0.6 MPa and at an average flow rate of 140 g/h.sup.−1. The temperature is maintained at 130° C. until a pressure level is reached. At the end of the addition, the mixture is left with stirring for one hour in order for all the propylene oxide to be consumed, then the residue is stripped with nitrogen for 1 hour at 80° C.

[0087] 1125 g of product are recovered in the form of a dark viscous liquid. The product is homogeneous and does not contain unreacted lignin grain. Its hydroxyl number (I.sub.OH) is 290 mg of KOH/g.sup.−1.

Example 2 (According to the Invention): Synthesis of Propoxylated Lignin in the Presence of PPG 400

[0088] 215 g of Indulin AT™ lignin, previously dried in an oven, in 500 g of polypropylene glycol 400 (PPG 400) and 8.6 g of finely ground caesium hydroxide are added into a 6 L autoclave. The weight ratio of lignin/PPG 400 is 43% by weight and the catalyst/lignin weight ratio is 4% by weight.

[0089] 3 purges are successively carried out with nitrogen. Leak tests are also carried out. The temperature is gradually increased with stirring of the reaction medium to 80° C. Nitrogen is re-pressurized to 0.25 MPa and then a 50 g fraction of propylene oxide is introduced. The temperature is gradually raised to a temperature of 130° C., at which temperature the attachment of the reaction can be observed.

[0090] The total propylene oxide, 500 g, is introduced at a temperature ranging from 130° C. to 140° C. and at a maximum pressure of 0.6 MPa and at an average flow rate of 85 g/h.sup.−1. The temperature is maintained at 130° C. until a pressure level is reached. At the end of the addition, the mixture is left with stirring for one hour in order for all the propylene oxide to be consumed, then the residue is stripped with nitrogen for 1 hour at 80° C.

[0091] 1100 g of product are recovered in the form of a dark viscous liquid. The product is homogeneous and does not contain unreacted lignin grain. Its hydroxyl number (I.sub.OH) is 202 mg of KOH/g.sup.−1.