Esterification
Acrylate Esters (MA, EA, BA, MMA, 2-EHA)
Acrylic acid and its esters are perhaps some of the most versatile monomers for improving performance characteristics to thousands of polymer formulations. Major markets for esters include coatings, textiles, adhesives, paper and plastics. Acrylic polymers are considered as nontoxic. Most of the acrylic acid is converted into its corresponding ester. Commodity acrylate esters are n-Butyl, ethyl, 2-ethylhexyl and methyl acrylates in order of decreasing importance. Speciality acrylate esters are made from isobutanol, isooctyl alcohol and several polyols such as Hydroxyalkyl, alkylalkanolamine and are manufactured in minor quantities to produce specialty polymeric materials.
The direct esterification of alcohol with acrylic acid is the only significant route for the production of esters. Some smaller volume esters are produced through transesterification. It is catalyzed by an acid such as sulfuric acid or a sulfonated styrene DVB copolymer. To optimize the catalyst performance different degrees of crosslinking and porosities are used to ensure high selectivity and conversion rate.
Direct esterification acrylic acid
with sulphonated styrene DVB copolymer
R1 = H acrylic acid - R2 = CH3 methacrylic acid
Typical Process conditions
|
Influent Composition |
Acrylic acid and alcohol |
|
Influent Temperature |
120 - 150 °C |
|
Conversion per pass |
up to 93-98% |
|
Typical Catalyst life |
up to 3 years |
Recommended Catalysts
| Monodisperse gel catalyst which confers enhanced hydraulic and reactivity properties compared to conventional catalysts. Suitable for fixed bed reactors. Recommended for EA. | |
| Macroreticular catalyst suitable particularly for stirred and slurry loop reactors. High conversion and very good lifetime. Recommended for BA. | |
| Amberlyst™ 46 | Specialty macroporous catalyst producing less ether byproducts than conventional catalyst (US Patent 5,426,199). Recommended for longer acid esters. |
| Amberlyst™16Wet | Macroporous catalyst. Good physical stability and long lifetime. Recommended for MMA. |
Amberlyst™ catalysts are approved by all major process licensors.
The catalyst choice depends very much on the type of ester and the process decisions.
For sampling, pricing and availability of AMBERLYST™ catalysts please contact your Rohm and Haas sales representative.
Further Reading
- X. Chen, Z. Xu, T. Okuhara, "liquid phase esterification of acrylic acid with 1-butanol catalyzed by solid acid catalysts", Appl. Catalysis 180 (1999) 261-269.
- Nippon Shokubai, "Process for production of carboxylic acid and ester and resin separating vessel used therein" (1999).
- Rohm and Haas, "Catalyzed esterification process" US 5,426,199 (1995).
