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 alkoxylated polyphenol as a solvent, the polyphenol/polyphenol alkoxylated weight ratio as a solvent being less than 2, preferably less than or equal to 1.5, more preferably less than or equal to 1, even more preferably less than or equal to 0.5; (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 alkoxylated polyphenol as a solvent, wherein the polyphenol/polyphenol alkoxylated weight ratio as a solvent is less than 2; and (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 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.

8. Process according to claim 1, wherein the polyphenol/alkoxylated polyphenol weight ratio as solvent ranges from 0.05 to 0.5.

9. Process according to claim 1, wherein the temperature in step (a) ranges from 70 C. to 200 C.

10. Process according to claim 1, wherein the pressure during step (a) ranges from 0.1 to 1.8 MPa.

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 the alkoxylated polyphenol obtained by the process as defined in claim 1, 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 surfactants, non-ionic or cationic surfactants, biosourced carbon fibre precursors.

Description

EXAMPLES

Example 1

Synthesis of a Propoxylated Lignin According to the Invention

[0080] In a 6 L autoclave, 500.4 g of propoxylated lignin obtained according to the process described in the aforementioned thesis are added, the operating procedure of which is specified on pages 97 and 98 (see table 4.8 Indulin AT, formulation 30/70/2 page 122), said process being repeated several times, and 144.8 g of previously dried lignin Indulin AT.

[0081] The weight ratio lignin/propoxylated lignin is 0.29 by weight and the catalyst/lignin weight ratio is 4.5% by weight.

[0082] 3 purges are successively carried out with nitrogen. Leak tests are also carried out. The temperature under stirring of the reaction medium is gradually increased to 110 C. Nitrogen stripping is carried out at this temperature and at 0.02 MPa to dry the medium for 1 hour. Nitrogen pressure at 0.286 MPa is activated and then a 45 g fraction of propylene oxide is introduced. The temperature is gradually increased to a temperature ranging from 140 C. to 150 C. At 145 C., attachment of the reaction is observed. The entire propylene oxide, i.e. 830 g, is introduced at a temperature of 150 C. and at a maximum pressure of 0.55 MPa at an average flow rate of 200 g/h. The temperature is maintained at 150 C. until a pressure level is reached. At the end of the addition, the mixture is left under stirring for one hour in order for all the propylene oxide to be consumed, the residue is then stripped with nitrogen for 1 hour at 100 C. 1455 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 160 mg of KOH/g.

Example 2

[0083] 5 successive batches are carried out according to the protocol described in Example 1. The propoxylated lignin used in the first batch is the product obtained in Example 1. Part of the product of each batch constitutes the propoxylated lignin of the following batch.

[0084] It is observed that the product of each batch is a homogeneous dark viscous liquid which does not contain unreacted lignin grain.