Process for making tricyclodecenyl esters
A process for making tricyclodecenyl esters is disclosed. A C 2 -C 4 carboxylic acid and a dicyclopentadiene react in the presence of triflic acid under conditions effective to produce the ester. The process gives tricyclodecenyl esters in good yield while avoiding the need to use a large excess of the carboxylic acid. The process efficiently provides fragrance-quality tricyclodecenyl esters from technical grade dicyclopentadienes and/or recycled carboxylic acids.
1 . A process comprising reacting a C 2 -C 4 carboxylic acid and a dicyclopentadiene at a carboxylic acid:dicyclopentadiene molar ratio within the range of 0.8 to 1.3 in the presence of triflic acid under conditions effective to produce a tricyclodecenyl ester.
2 . The process of claim 1 wherein the dicyclopentadiene is unsubstituted dicyclopentadiene (DCPD).
3 . The process of claim 1 wherein the dicyclopentadiene has a purity within the range of 80 to 90%.
4 . The process of claim 1 wherein the tricyclodecenyl ester is distilled to produce a commercially acceptable fragrance component.
5 . The process of claim 1 wherein the carboxylic acid is selected from the group consisting of acetic, propionic, n-butyric, and isobutyric acids.
6 . The process of claim 5 wherein the carboxylic acid is acetic acid having a purity within the range of 80 to 95%.
7 . The process of claim 5 wherein the carboxylic acid is acetic acid, the dicyclopentadiene is DCPD, and the tricyclodecenyl ester is tricyclodecenyl acetate (TCDA).
8 . The process of claim 7 wherein the DCPD is added gradually to a mixture comprising acetic acid and triflic acid.
9 . The process of claim 7 wherein a TCDA-rich product is recovered by distillation.
10 . The process of claim 9 wherein the product comprises at least 95 wt. % of TCDA isomers.
11 . The process of claim 10 wherein the product comprises at least 98 wt. % of TCDA isomers.
12 . The process of claim 10 wherein the product has an index of refraction (n D 20 ) within the range of 1.49 to 1.50.
13 . The process of claim 10 wherein the product has a specific gravity (d 4 20 ) within the range of 1.07 to 1.08.
14 . The process of claim 1 wherein the molar ratio is within the range of 0.9 to 1.1.
15 . The process of claim 14 wherein the molar ratio is within the range of 0.95 to 1.05.
16 . The process of claim 1 wherein the amount of triflic acid is less than 1 wt. % based on the amount of the dicyclopentadiene.
17 . The process of claim 16 wherein the amount of triflic acid is less than 0.5 wt. % based on the amount of the dicyclopentadiene.
18 . The process of claim 1 wherein the reaction is performed at a temperature within the range of 60° C. to 150° C.
19 . The process of claim wherein the reaction is performed at a temperature within the range of 110° C. to 140° C.
20 . The process of claim 1 performed in batch, semi-continuous, or continuous mode.