PROCESS FOR ESTERIFICATION AND TRANS-ESTERIFICATION REACTIONS

Abstract

A process for esterification and/or trans-esterification, uses an acid as catalyst in the presence of an anionic surfactant. The process may involve esterifying and/or trans-esterifying at least one fatty acid and/or fatty acid ester with at least one alcohol using at least one acid catalyst, such as methanesulfonic acid, in the presence of at least one anionic surfactant

Claims

1. A process, comprising: esterifying and/or trans-esterifying a first reagent comprising a fatty acid and/or a fatty acid ester with a second reagent comprising an alcohol using a catalyst comprising methanesulfonic acid in the presence of an agent comprising an anionic surfactant.

2. The process of claim 1, wherein the alcohol comprises a mono-alcohol.

3. The process of claim 1, wherein the alcohol comprises methanol, ethanol, propanol, and/or butanol.

4. The process of claim 1, wherein the alcohol comprises methanol.

5. The process of claim 1, wherein the alcohol is methanol.

6. The process of claim 1, wherein the fatty acid is different from the methanesulfonic acid.

7. The process of claim 1, wherein the fatty acid comprises a saturated fatty acid and/or an unsaturated fatty acid.

8. The process of claim 1, wherein the fatty acid comprises 12 to 20 carbon atoms.

9. The process of claim 1, wherein the fatty acid comprises a saturated fatty acid and/or an unsaturated fatty acid comprising 12 to 20 carbon atoms.

10. The process of claim 1, wherein the fatty acid comprises oleic acid, palm fatty acid, linoleic acid, stearic acid, laurylic acid, and/or cetyl acid.

11. The process of claim 1, wherein the fatty acid is obtained from rape seed oil, soy bean oil, tallow, used cooking oil, and/or palm distilled fatty acid.

12. The process of claim 1, wherein the fatty acid ester comprises a saturated fatty acid ester and/or an unsaturated fatty acid ester.

13. The process of claim 1, wherein the fatty acid ester comprises 12 to 20 carbon atoms.

14. The process of claim 1, wherein the fatty acid ester comprises an ester of a saturated fatty acid comprising 12 to 20 carbon atoms and/or an unsaturated fatty acid comprising 12 to 20 carbon atoms.

15. The process of claim 1, wherein the fatty acid ester comprises an ester of glycerine.

16. The process of claim 1, wherein the fatty acid ester comprises a triglyceride.

17. The process of claim 1, wherein the fatty acid ester comprises rape seed oil, soy bean oil, palm oil, palm kernel oil, coconut oil, sunflower oil, sunflower kernel oil, castor oil, olive oil, canola oil, and/or tallow.

18-20. (canceled)

21. The process of claim 1, wherein the methanesulfonic acid is dissolved in water.

22. The process of claim 1, wherein the methanesulfonic acid is dissolved in water, and wherein the methanesulfonic acid has a concentration in the water of more than 60 wt %.

23. The process of claim 1, wherein the anionic surfactant comprises a hydrophobic group and a water-solubilizing anionic group comprising a sulfate, sulfonate, and/or carboxylate.

24. The process of claim 1, wherein the anionic surfactant has a molecular weight Mw in a range of from 300 to 600 g/mol, and/or wherein the anionic surfactant comprises a sulfonate.

25. (canceled)

26. The process of claim 1, wherein the anionic surfactant comprises a salt of a C12-C18 alkylsulfonic acid, a salt of a C12-C18 sulfonated fatty acid alkyl ester, a salt of a C10-C18-alkylarylsulfonic acid, and/or a salt of a C10-C18 alkyl alkoxy carboxylate.

27. The process of claim 1, wherein the methanesulfonic acid, is in an amount in a range of from 0.1 to 5 wt %, relative to an oil phase weight.

28. The process of claim 1, wherein the anionic surfactant is in an amount in a range of from 0.05 to 3 wt. %, relative to an oil phase weight.

29. The process of claim 1, wherein the esterifying and/or trans-esterifying is done in an open or closed system, at a temperature in a range of from 60 to 150 C.

30. The process of claim 1, wherein the alcohol is added in a stochiometric molar excess in a range of from 1 to 20 times and/or is added continuously until reaction is finished.

31. The process of claim 1, wherein the reaction is done in batches with subsequent separation of oil and a water/glycerin/alcohol phase, or continuously with constant evaporation of a water/alcohol.

32. A catalysts configured for a esterification and/or trans-esterification reaction, comprising; methanesulfonic acid A; and an anionic surfactant comprising a hydrophobic group and a water-solubilizing anionic group, wherein the water-solubilizing anionic group comprises a sulfate, sulfonate, and/or carboxylate.

33. (canceled)

34. A process for enhancing a catalytic activity of the methanesulfonic acids in the esterifying and/or trans-esterifying of the process of claim 1, the method comprising: combining with the methanesulfonic acid the anionic surfactant which comprises a hydrophobic group and a water-solubilizing anionic group, wherein the water-solubilizing anionic group comprises a sulfate, sulfonate, and/or carboxylate.

35-36. (canceled)

Description

EXAMPLES

[0054] In the following, some examples are described in detail, which may serve to illustrate some aspects of the present invention.

[0055] Unless otherwise noted, percentages are given as % by weight.

[0056] A) Esterification

[0057] Test Series 1

[0058] For all tests, a model feedstock (fatty acid triglyceride mixture) of following composition was used: 80% oleic acid, 20% rape seed oil.

[0059] Approximately 300 grams of the model feedstock were filled into a 500 ml glass reactor with reflux condenser and dosing unit. The desired amount of methanol was added. Condenser cooling, stirrer and heating were turned on. Once reaction temperature is reached (reflux), the desired amount of catalyst (Lutropur MSA-XP) and surfactant additive according to present invention was added to start the reaction. After reaction was started, each 30 minutes a sample was taken, the biodiesel and water phase separated in a separating funnel and the biodiesel phases kept for later analysis. After 3 hours the reaction mixture was cooled down and transferred into a separating funnel, where the biodiesel phase and the water phase were separated and a sample of the biodiesel phase taken for analysis.

[0060] The esterification was done under the following conditions:

Methanol content: 20% w/w
Lutropur MSA-XP: 1% (w/w) active matter

Surfactant: q.s.

[0061] Temperature: reflux (approx. 65 C.)
Duration: 3 hours
(Lutropur MSA-XP is a product of BASF SE, methanesulfonic acid, approximately 94% by weight in water, CAS no. 75-75-2)

[0062] All samples from the biodiesel phase taken during the experiment were analyzed for the acid value by titration with KOH according to EN 14104. The lower the acid value, the more free fatty acid have been converted to biodiesel (fatty acid methyl ester; FAME).

[0063] The following surfactants (commercially available products) were used.

Dehyquart SP (Tallow alkyl amine, ethoxylated, phosphates)
Disponil OCS 27 (Aqueous solution based on: Sulfuric acid, mono(C16-18 and C18-unsatd. alkyl) esters, sodium salts)
Pluriol E400 (polyethylene glycol, average molar mass 400)
Disponil OSS 50 KS (9(or 10)-Sulphooctadecanoic acid, potassium salt)
Lutensit A-EP (Oxirane, methyl-, polymer with oxirane, mono-C10-16-alkyl ethers, phosphates)
Aliquat 336 (Quaternary ammonium compounds, tri-C8-10-alkylmethyl, chlorides)
Disponil SUS IC 10 (Na salt of Di-isodecylsulphosuccinate)
Aliquat 175 (Tributylmethylammonium chloride)
Disponil LDBS 55 (Benzenesulfonic acid, C10-13-alkyl derivs., sodium salts)

[0064] The experimental results (acid values) are shown in table 1.

TABLE-US-00001 TABLE 1 Acid Value Surfactant [mg KOH/g] No surfactant (1% MSA only) 48.9 Pluriol E400 45.9 Aliquat 336 46.0 Aliquat 175 47.2 Lutensit A-EP 47.9 Disponil OSS 50 KS 28.4 Disponil SUS IC 10 16.5 Disponil LDBS 55 18.0

[0065] The best results were achieved with Disponil OSS 50 KS, Disponil SUS IC 10 and Disponil LDBS 55, which could increase the catalytic activity of MSA significantly.

[0066] These three surfactants stem from the class of sulfonate-based surfactants.

[0067] Test Series 2

[0068] Using the same methodology as in test series one, the surfactant concentrations were varied at a constant MSA level of 1% w/w (active). Only the three best surfactants from test series 1 were used.

[0069] The results of this test series 3 are shown in table 2.

TABLE-US-00002 TABLE 2 Acid Value Surfactant [mg KOH/g] No surfactant 48.9 (1% MSA only) 0.2% Disponil OSS 50 KS 38.7 0.5% Disponil OSS 50 KS 37.7 0.2% Disponil SUS IC 10 35.0 0.5% Disponil SUS IC 10 21.8 0.2% Disponil LDBS 55 33.3 0.5% Disponil LDBS 55 22.0

[0070] All processes using a surfactant additive additionally to MSA showed better performance than MSA stand-alone, both at 0.2% w/w and 0.5% w/w of the additive.

[0071] Test Series 3

[0072] Tests were carried out using the same methodology as in test series 1. In this test series 4, MSA concentrations and surfactant concentrations were varied and compared to MSA stand-alone. Disponil SUS IC 10 was used for these tests.

[0073] This resulted in following catalyst combinations:

TABLE-US-00003 Disponil MSA SUS IC 10 Cat 0.7/0.2 0.7% w/w 0.2% w/w Cat 0.7/0.5 0.7% w/w 0.5% w/w Cat 0.5/0.2 0.5% w/w 0.2% w/w Cat 0.5/0.5 0.5% w/w 0.5% w/w 0.5% MSA 0.5% w/w 0.0% w/w 0.7% MSA 0.7% w/w 0.0% w/w 1% MSA 1.0% w/w 0.0% w/w

[0074] Cat 0.5/0.5 performed better than 1% MSA, despite the overall proton concentration being less in this catalyst combination.

[0075] The results are shown in table 3:

TABLE-US-00004 TABLE 3 Acid Value Cat System [mg KOH/g] Cat 0.7/0.2 40 Cat 0.7/0.5 29 Cat 0.5/0.2 49 Cat 0.5/0.5 34 0.5% MSA 58 0.7% MSA 52.9 1% MSA 41.8

[0076] Test Series 4 (Sulfur Content)

[0077] Various samples of FAME from above test series were washed with water until washing water was neutral, and then analyzed for sulfur content.

[0078] If the surfactants would not wash out as easily as MSA, the resulting biodiesel would be contaminated with surfactants, increasing the sulfur content and potentially impacting phase separation.

TABLE-US-00005 sulfur content of FAME Catalyst system (mg/Kg) MSA (1%) + Disponil SUS IC 10 (0.2%) 17 MSA (1%) + Disponil SUS IC 10 (0.5%) 20 MSA (0.7%) + Disponil SUS IC 10 (0.2%) 29 MSA (0.7%) + Disponil SUS IC 10 (0.5%) 17 MSA (0.5%) + Disponil SUS IC 10 (0.2%) 18 MSA (0.5%) + Disponil SUS IC 10 (0.5%) 22 MSA (0.5%) 24 MSA (0.7%) 12 MSA (1%) 13

[0079] The sulfur content of all tested samples was similar. There is no indication of increased sulfur content when combining MSA with a sulfonic acid based surfactant, thus there are no unwanted surfactants in the biodiesel phase after reaction and washing.

[0080] B) Trans-Esterification

[0081] It was tested if the positive effects found for esterification would also be found under transesterification conditions. The following process was utilized:

[0082] All ingredients were weight into an autoclave. The autoclave was closed, stirrer and heating started and the reaction run for 3 hours. Afterwards, the reaction mixture was transferred into a separating funnel and biodiesel phase and water/glycerin phase separated. The acid value of the biodiesel phase was then determined as described above. The lower the acid value, the better conversion to FAME. Additionally, samples were analyzed to determine the actual FAME content.

[0083] The transesterification reactions were carried out under the following conditions:

Model feedstock
50% oleic acid
50% rape seed oil

Methanol: 30% w/w

[0084] Lutropur MSA-XP: 1% w/w active matter
Surfactant: 1% w/w active matter

Temperature: 130 C.

[0085] Pressure: approx. 3.5 bar
Duration: 3 hours

[0086] Both tested additives, Disponil OSS 50 KS and Disponil LDBS 55, exhibited in combination with MSA lower acid values and higher FAME content compared to MSA stand-alone. Thus these surfactants increased the overall yield of the transesterification, despite the amount of catalytically active protons being the same in all three experiments. The results are shown in table 4:

TABLE-US-00006 TABLE 4 Acid Value FAME [mg KOH/g] [%] MSA 7.1 81.9 Disponil OSS 50 KS 6.2 89.6 Disponil SUS IC 10 8.2 84.6 Disponil LDBS 55 5.0 90.5

[0087] FIG. 1 shows, for illustration purposes, the chemical formulae of some exemplary anionic surfactants.