Method for stabilizing a composition containing at least one product of internal dehydration of a hydrogenated sugar, resulting composition and uses thereof

Abstract

A method for improving the stability of compositions of a product for internal dehydration of a hydrogenated sugar, in particular an isosorbide composition, the method involving the use of monoethanolamine, diethanolamine, triethanolamine and the mixtures thereof as a stabilization agent. The resulting compositions and their various uses thereof are also described.

Claims

1. A method for preparing a composition of internal dehydration product of a hydrogenated sugar, comprising: a) a step of distilling a medium containing said internal dehydration product in order to obtain a distillate enriched in this product, b) optionally, at least one subsequent step of purifying the distillate thus obtained, c) a subsequent step of bringing together the distillate obtained during step a), and then optionally subjected to step b), and an agent capable of improving the stability of the internal dehydration product predominantly contained in the distillate, said agent not being in gaseous form, d) optionally, a subsequent step of shaping the resulting composition of internal dehydration product of a hydrogenated sugar, and wherein the agent used in step c) is chosen from monoethanolamine, diethanolamine and triethanolamine, and mixtures thereof.

2. The method as claimed in claim 1, wherein the agent used in step c) is chosen from diethanolamine and triethanolamine, and mixtures thereof.

3. The method as claimed in claim 1, wherein the agent used in step c) is used in a proportion of from 0.0001% to 2%, these percentages being expressed by dry weight of improving agent relative to the dry weight of the internal dehydration product of hydrogenated sugar then predominantly present in the distillate.

4. The method as claimed in claim 1, wherein the distilling step a) is followed by a purifying step b), during which the distillate is treated, in any order, with at least one activated carbon and with at least one ionic or nonionic resin.

5. The method as claimed in claim 1, wherein it comprises at least one concentrating step.

6. The method as claimed in claim 1, wherein the internal dehydration product of a hydrogenated sugar is isosorbide.

7. A composition containing at least one internal dehydration product of a hydrogenated sugar, containing from 0.0001% to 2%, of an improving agent chosen from monoethanolamine, diethanolamine and triethanolamine, and mixtures thereof, these percentages being expressed by dry weight of improving agent relative to the dry weight of the internal dehydration product of hydrogenated sugar then predominantly present in said composition.

8. The composition as claimed in claim 7, wherein the internal dehydration product of a hydrogenated sugar is isosorbide.

9. The composition as claimed in claim 7, wherein it has a solids content of between 50% and 90%.

10. The composition as claimed in claim 7, wherein it has a solids content of 100%.

11. Polymeric or non-polymeric, biodegradable or non-biodegradable products and mixtures intended for the chemical, pharmaceutical, cosmetological or food industries, prepared from the composition as claimed in claim 7.

Description

EXAMPLES

Example 1

(1) This example relates to the production of an isosorbide composition according to the prior art (use of disodium phosphate) and according to the invention (use of monoethanolamine, diethanolamine and triethanolamine). It illustrates the increase in the duration of stability of said compositions in the context of the invention, through the monitoring of the pH of these compositions over time.

(2) 1 kg of a solution of sorbitol with a 70% solids content sold by the applicant under the name Neosorb 70/02 and 7 g of concentrated sulfuric acid are placed in a jacketed stirred reactor. The mixture obtained is heated under vacuum (pressure of approximately 100 mbar) for 5 hours so as to remove the water contained in the initial reaction medium and that originating from the sorbitol dehydration reaction.

(3) The reaction crude is then cooled to around 100 C. and then neutralized with 11.4 g of a 50% sodium hydroxide solution. The isosorbide composition thus neutralized is then distilled under vacuum (pressure below 50 mbar).

(4) The crude isosorbide distillate, which is slightly colored (pale yellow color), is then dissolved in 2-propanol, at a temperature of 60 C., so as to obtain a solution with a 75% solids content. This solution is then slowly cooled, in the space of 5 hours, to a temperature of 10 C.; a recrystallized isosorbide seed is added at 40 C.

(5) The crystals are then drained in a centrifuge and washed with a small amount of 2-propanol. After drying under vacuum, the crystals are redissolved in water so as to obtain a solids content of 40%.

(6) This solution is then percolated on a column of granular active carbon CPG 12-40 at a rate of 0.5 BV/h (Bed Volume/hour). The decolorized isosorbide composition thus obtained is then passed, at a rate of 2 BV/h, successfully over a column of Purolite C 150 S strong cationic resin and then a column of Amberlite IRA 910 strong anionic resin. This solution is then treated with powdered active carbon of Norit SX+ type at 20 C. for 1 hour. The active carbon is used in a proportion of 0.5% expressed by dry weight/dry weight of solution.

(7) The agent to be tested, that is to say: 0.005% of disodium phosphate (dry weight/dry weight of isosorbide contained in the composition) for test No. 1; 0.0025% of monoethanolamine (dry weight/dry weight of isosorbide contained in the composition), for test No. 2; 0.0025% of diethanolamine (dry weight/dry weight of isosorbide contained in the composition), for test No. 3; 0.0025% of triethanolamine (dry weight/dry weight of isosorbide contained in the composition), for test No. 4;
is then introduced into said composition.

(8) After filtration, the isosorbide solution is concentrated under vacuum. The molten mass obtained crystallizes on cooling in the form of a massed product of large crystals which is subsequently ground to obtain a white-colored powder having a moisture content of 0.2%.

(9) 200 g of this isosorbide massed product are directly introduced into a glass container having a volume of 500 ml which, after having been hermetically closed, is placed in an oven maintained at 50 C.

(10) For each of the flasks corresponding to tests No. 1, 2, 3 and 4, the change in pH over time is monitored. The results appear in table 1. The pH measurement is carried out on a Radiometer Analytical PHM 220 pH-meter equipped with a Mettler Toledo combined Ag/AgCl wire electrode, calibrated beforehand using pH 7 and 4 buffer solutions. The pH is measured on a sample of product dissolved at 40% by weight of solids content in osmosed water.

(11) It is clearly verified that only tests No. 2, 3 and 4 have a pH which is advantageously stable over time for at least 3 months, it being possible for this period to reach 6 months in the case of tests No. 3 and 4 corresponding to diethanolamine and to triethanolamine.

(12) TABLE-US-00001 TABLE 1 Agent according to step c) pH Amount t = 1 t = 1.5 t = 2 t = 2.5 t = 3 t = 4 t = 5 t = 6 Test No. Nature (% dry/dry) t = 0 month months months months months months months months 1 disodium 0.005 7.9 7.8 7.9 7.7 3.3 phosphate 2 monoethanol- 0.0025 7.4 7.3 6.8 6.9 3.2 amine 3 diethanol- 0.0025 7.8 7.6 7.5 7.5 7.5 7.5 7.5 amine 4 triethanol- 0.0025 7.9 7.7 8 7.9 7.7 7.7 7.8 amine

Example 2

(13) This example relates to the production of an isosorbide composition according to the prior art (use of sodium hydroxide, of ascorbic acid, of tocopherol, of sodium metaborate, of morpholine and of butylated hydroxy-toluene) and according to the invention (use of diethanolamine and triethanolamine). It illustrates the increase in the duration of stability of said compositions in the context of the invention, through the monitoring of the pH according to a protocol identical to that described in the previous example.

(14) The only difference lies in the fact that the oven is maintained at 60 C., thereby making the tests much more discriminating, it being possible for differences to be observed over a period of a few days.

(15) The results appear in table 2.

(16) It is thus clearly shown that the best stabilities are obtained for diethanolamine and triethanolamine.

(17) TABLE-US-00002 TABLE 2 Stabi- Ascor- To- Na Mor- lizing bic coph- meta- pho- agent DEA TEA NaOH acid erol borate line BHT T = 0 8.3 7.7 9.1 4.9 5.3 8.5 7.9 6.9 T = 2 8.6 8.0 8.0 4.3 3.5 8.6 7.8 3.9 days T = 3 8.5 8.0 8.0 3.9 3.3 7.9 7.2 3.5 days T = 5 8.0 8.0 7.4 3.5 3.2 7.7 7.1 3.4 days