Process for reacting an α, β-unsaturated dicarboxylic acid compound with an ethylenically unsaturated hydrocarbon
View Patent ↗The invention provides an improved method of synthesizing chemicals according to the ene reaction. The method addresses two problems that previously could not be addressed simultaneously, preventing charring of the reaction, and preventing gaseous degradation of the reagents. The method involves adding a boron bearing compound and an aromatic/antioxidant compound to the ene reaction. Combining these two compounds together inhibits charring and also causes an effect that neither compound can accomplish alone. The addition of these two compounds together also more effectively prevents either of the reagents from degrading than when either reagent is added alone. As a result the method reduces costs by reducing the amount of reagents needed for a synthesis and further reduces costs by eliminating the need to filter out char from the end products of the ene reaction. The method is particularly useful in the ene reaction synthesis of ASA from olefins and maleic anhydride.
1. A method of synthesizing alkenyl succinic anhydride comprising:
reacting two reagents one of which is an olefin and one of which is a maleic anhydride, according to an ene reaction for at least 7 hours to form a product which comprises alkenyl succinic anhydride; and
adding a boron bearing compound and an aromatic/antioxidant compound to at least one of the reagents prior to the reaction, wherein:
the ratio of boron bearing compound to aromatic/antioxidant compound is within the range of 8:1 to 21:1 and thereby are in an amount effective in reducing char formation, and are in an amount effective in reducing the degradation of at least one of the reagents into a gas by at least one of the compounds,
the molar amount of olefin is no more than 20% of the molar amount of the maleic anhydride and no significant char results from the reaction and the yield of the alkenyl succinic anhydride is greater than a similar reaction in which the molar amount of olefin is at least more than 50% of the molar amount of the maleic anhydride and the ratio of boron bearing compound to aromatic/antioxidant compound is 1:1, and
the boron bearing compound and the aromatic/antioxidant compound are added in an amount effective in reducing the degradation of at least one of the reagents into at least one gas selected from the list consisting of: carbon dioxide, carbon monoxide, and ethyne.
2. The method of claim 1 wherein the olefin is an unsaturated α,β-dicarboxylic acid compound.
3. The method of claim 1 wherein the boron bearing compound is boric oxide.
4. The method of claim 1 wherein the aromatic/antioxidant compound is selected from the list consisting of butylated hydroxytoluene, a phenolic compound which is sterically hindered so it inhibits the reaction, and an aniline compound which is sterically hindered so it inhibits the reaction.
5. The method of claim 1 wherein the boron bearing compound is added into the ene reaction at a level in excess of 50 ppm.
6. The method of claim 1 wherein an antioxidant is also added to the ene reaction.
7. The method of claim 1 wherein an acid is also added to the ene reaction.
8. The method of claim 1 wherein the boron bearing compound is added to a level of 100 ppm.
9. The method of claim 1 wherein the aromatic compound is added to a level of 1800 ppm.
10. The method of claim 1 wherein one of the reagents is maleic anhydride.
11. The method of claim 1 wherein one of the reagents is an 18-carbon olefin.
12. The method of claim 1 in which the boron bearing compound is an oxygen-boron bearing compound.
13. The method of claim 1 in which the char formation is reduced to such an extent that when the product of the ene reaction is passed through a 100 μm filter, no char is deposited on the filter.