Experimental and Modeling Study of Esterification Reaction for Synthesis of Butyl Butyrate: Desirability Function Approach for Optimization and Prediction Comparative Study of RSM and ANN

Author(s):  
Chandrakant R. Khudsange ◽  
Kailas L. Wasewar

Abstract Butyl butyrate was synthesized by esterification of butyric acid with n-butanol using homogeneous catalyst methanesulfonic acid (MSA). The esterification process was optimized by the application of response surface methodology (RSM) and artificial neural network (ANN). 3 level-4 variables central composite design (CCD) of RSM and MLP 4-9-1 network of ANN was chosen for the experimental design and analysis. The quadratic response model of RSM was optimized using desirability function approach. Effects of independent variables on the yield of butyl butyrate were investigated. Various training algorithm such as IBP, QP, GA, LM, BFGS, and CG was used for training experimental response data for the ANN study. By sensitivity analysis, the relative significance of 36.98 % confirmed that the molar ratio was the main affecting parameter on the yield of butyl butyrate. In prediction comparative study, ANN model was found better than the RSM model with high values of R2 (0.9998) and lower values of RMSE (0.2435), SEP (0.324 %), and AAD (0.0086 %) compared to RSM (R2=0.9862, RMSE=2.3095, SEP=3.076 %, AAD=0.6459 %). The accuracy of the RSM and ANN models were judged by validation test by performing unseen data experiments.

2017 ◽  
Vol 79 (7) ◽  
Author(s):  
Ida Nurhazwani Abd Rahman ◽  
Fatin Myra Abd Manan ◽  
Nur Haziqah Che Marzuki ◽  
Naji A. Mahat ◽  
Nursyafreena Attan ◽  
...  

Being the prevailing approach for producing esters such as butyl butyrate, the use of chemical route has been linked to numerous disadvantages. Hence, a green alternative method for higher yield production of butyl butyrate by esterification reaction utilizing Novozyme 435 as biocatalysts in a solvent-less system may prove useful. Such approach can be further improved by optimizing the relevant reaction parameters using the Response Surface Methodology by the Box-Benkhen Design attempted in this present study. The reaction parameters evaluated were: substrate molar ratio, time and temperature, and the response of each parameter was measured as percentage conversion yield. Using the Design Expert 7.1.6 optimization functions, the two sets of optimum conditions selected viz. [i] molar ratio butyric acid:butanol 1:3.93, 9.93 h at 56.09°C and [ii] molar ratio butyric acid:butanol 1:3.35, 9.79 h at 53.90°C had afforded the highest yield of butyl butyrate i.e. 99.62% and 99.55%, respectively. The ester product obtained from the reaction were confirmed as butyl butyrate by FTIR and GC. Therefore, the results substantiated the applicability of the RSM prediction technique as well as efficacy of Novozyme 435 as biocatalysts in the high yield solvent-less synthesis of butyl butyrate, adhering to the philosophy of Green Chemistry.


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