METHOD FOR PREPARING A FATTY AMIDOALKYLDIALKYLAMINE

Abstract

The present invent ion concerns a method for preparing a fatty amidoalkyldialkylamine by reacting a fatty acid with a dialkylaminoalkylamine, using a molar ratio of said dialkylaminoalkylamine to said fatty acid of more than 1 and up to 1.5, in the presence of Candida antarctica lipase as catalyst.

Claims

1. A method for preparing at least one fatty amidoalkyldialkylamine by reacting at least one fatty acid containing from 8 to 24 carbon atoms with at least one dialkylaminoalkylamine of formula (I): ##STR00005## in which: R.sub.1 represents a divalent alkyl group containing from 2 to 6 carbon atoms; R.sub.2 and R.sub.3 represent, independently of each other, monovalent alkyl groups containing from 1 to 4 carbon atoms, using a molar ratio of said dialkylaminoalkylamine to said fatty acid of more than 1 and up to 1.5, in the presence of Candida antarctica lipase as catalyst.

2. The method of claim 1, wherein the fatty acid(s) contain from 10 to 20 carbon atoms.

3. The method of claim 1, wherein the fatty acid(s) are chosen from lauric acid, stearic acid, oleic acid, and mixtures thereof, as well as mixtures of fatty acids comprising from 8 to 18 carbon atoms.

4. The method of claim 3, wherein the fatty acid(s) are chosen from lauric acid and stearic acid.

5. The method of claim 1, wherein in formula (I), R.sub.1 represents a divalent alkyl group containing 3 or 4 carbon atoms.

6. The method of claim 1, wherein in formula (I), the R.sub.2 and R.sub.3 groups are identical.

7. The method of claim 1, wherein the dialkylaminoalkylamine of formula (I) is dimethylaminopropyl amine.

8. The method of claim 1, wherein the molar ratio of dialkylaminoalkylamine(s) to fatty acid(s) ranges from 1.05 to 1.3.

9. The method of claim 1, wherein the catalyst is under the form of a solid catalyst containing Candida Antarctica lipase grafted onto a polymeric support.

10. The method of claim 1, wherein Candida Antarctica lipase is present in an amount ranging from 0.2 to 2% by weight, with regard to the total weight of fatty acid(s).

11. The method of claim 1, wherein the reaction is carried out at a temperature within the range from 75 to 120° C.

12. The method of claim 1, wherein the reaction is carried out under vacuum, at a pressure ranging from 25.102 to 200.102 Pa.

13. The method of claim 1, wherein the reaction is carried out in a batch reactor.

14. The method of claim 13, wherein after a first reaction cycle the catalyst is recycled to the batch reactor where it is reused for a next reaction batch.

15. The method of claim 2, wherein the fatty acid(s) contain from 12 to 18 carbon atoms.

16. The method of claim 6, wherein in formula (I), the R.sub.2 and R.sub.3 groups both represent methyl groups.

17. The method of claim 8, wherein the molar ratio of dialkylaminoalkylamine(s) to fatty acid(s) ranges from 1.1 to 1.2.

18. The method of claim 9, wherein the polymeric support is an anionic resin.

19. The method of claim 18, wherein the anionic resin is an acrylic resin.

20. The method of claim 10 wherein Candida Antarctica lipase is present in an amount ranging from 0.5 to 1.5% by weight, with regard to the total weight of fatty acid(s).

Description

EXAMPLES

Example 1: Synthesis of Lauramidopropyldimethylamine by Reacting Lauric Acid with Dimethylaminopropylamine

[0055] The syntheses were carried out in a jacketed reactor having a volume of 250 mL coupled with a vacuum pump, a condenser, a mechanic stirrer and a peristaltic pump for amine feeding.

[0056] The reactions were performed at 95° C., under vacuum at 50-100 mbar, mechanical agitation, and with a fed-batch of amine. First, the lauric acid was introduced into the reactor. It can be melted in the reactor or be melted previously to the addition. Then, the enzymatic catalyst was added. The catalyst used was the commercial product Novozym 435 which contains 21% by weight of Candida Antarctica lipase originating from Candida Antarctica B, grafted onto an acrylic resin.

[0057] The amount of enzyme (active matter, ie excluding the support) used corresponds to 1% w/w based on lauric acid.

[0058] The stoichiometric amount of dimethylaminopropylamine (DMAPA) plus 10% of excess was added continuously into the reactor for a period of 7 hours. After 7 hours of feeding, the acid index was monitored for each hour. When it became constant, amine excess was added, divided into portions of 1%.

[0059] For the first reaction batch, a rate of 99.5% of conversion was achieved with 11% (molar) of amine excess. The total reaction time was around 15 hours.

[0060] After the reaction, the agitation was turned off for the enzymatic catalyst to go to the bottom of the reactor. The product was removed from the top. Acid index and residual amine were measured to certify that all specifications were achieved.

[0061] After removal of the product (end of cycle 1), a new reaction cycle was performed using the catalyst remaining in the reactor: a new charge of lauric acid was added, and the feeding of dimethyl aminopropylamine was started. Three successive reaction cycles were achieved using the same load of catalyst.

[0062] The table hereunder summarizes the conditions and results of the reaction for the three successive cycles.

TABLE-US-00001 Cycle 1 Cycle 2 Cycle 3 Amount of lauric acid (g) 113.65 113.65 113.64 Amount of lauric acid 0.57 0.57 0.57 (mol) Amount of DMAPA (g) 64.25 65.35 65.78 Amount of DMAPA (mol) 0.63 0.64 0.64 Excess of amine vs 11 12.3 12.3 stoechiometric amount (mol %) Mass of Novozym 435.sup.(*.sup.) 5.77 5.77 (recycled) 5.77 (recycled) catalyst (g) Reaction time (h) 15 21 30.5 Final acid index (mg 0.83 0.54 0.73 kOH/g) Free fatty acid 0.32 0.21 0.28 remaining (% by weight) Conversion (%) 99.54 99.7 99.59 .sup.(*.sup.)contains 21% by weight of Candida Antarctica lipase

Example 2: Synthesis of Stearamidopropyldimethylamine by Reacting Stearic Acid with Dimethylaminopropylamine

[0063] The synthesis was carried out in a jacketed reactor having a volume of 250 mL coupled with a vacuum pump, a condenser, a mechanic stirrer and a peristaltic pump for amine feeding.

[0064] The reaction was performed at 95° C., under vacuum at 50-100 mbar, mechanical agitation, and with a fed-batch of amine. First, the stearic acid was introduced into the reactor. It can be melted in the reactor or be melted previously to the addition. Then, the enzymatic catalyst was added. The catalyst used was the commercial product Novozym 435 which contains 21% by weight of Candida Antarctica lipase originating from Candida Antarctica B, grafted onto an acrylic resin.

[0065] The amount of enzyme (active matter, ie excluding the support) used corresponds to 1% w/w based on lauric acid.

[0066] The stoichiometric amount of dimethylaminopropylamine (DMAPA) plus 10% of excess was added continuously into the reactor for a period of 7 hours. After 7 hours of feeding, the acid index was monitored for each hour. When it became constant, amine excess was added, divided into portions of 1%.

[0067] A rate of 99.2% of conversion was achieved with 18% (molar) of amine excess. The total reaction time was around 20 hours.

[0068] After the reaction, the agitation was turned off for the enzymatic catalyst to go to the bottom of the reactor. The product was removed from the top. Acid index and residual amine are measured to certify that all specifications were achieved.

[0069] The table hereunder summarizes the conditions and results of the reaction for the synthesis.

TABLE-US-00002 Amount of stearic acid (g) 129.39 Amount of stearic acid (mol) 0.45 Amount of DMAPA (g) 54.74 Amount of DMAPA (mol) 0.54 Excess of amine vs stoechiometric amount (mol %) 20 Mass of Novozym 435.sup.(*.sup.) catalyst (g) 6.46 Reaction time (h) 20 Final acid index (mg kOH/g) 1.16 Free fatty acid remaining (% by weight) 0.45 Conversion (%) 99.2 .sup.(*.sup.)contains 21% by weight of Candida Antarctica lipase

[0070] The examples above show that the method of the invention provides an efficient route for the synthesis of fatty amidoalkyldialkylamines.

[0071] The benefits of the enzymatic process of the invention in particular versus chemical synthesis are the reduction of dialkylaminoalkylamine raw material from 30 to 10-13% and the reduction of the temperature. Both parameters have a significant impact on the process costs.

[0072] Furthermore in the chemical synthesis, after specifying acidity content, another step is required in order to remove residues of DMAPA, which is not needed in the method of the invention.