Pengaruh Suhu pada Esterifikasi Amil Alkohol dengan Asam Asetat Menggunakan Asam Sulfat sebagai Katalisator

Abstract

Ester compounds are widely used as solvents, artificial aroma materials, and precursors of pharmaceutical ingredients. One of the ester compounds widely used in the chemical industry is amyl acetate. Amyl acetate can be synthesized by esterification of amyl alcohol and acetic acid, which is a liquid-liquid heterogeneous reaction. This study aims to study the kinetics of this particular reaction focusing on the effect of temperature. The catalyst used in this study was sulfuric acid. The mole ratio of acetic acid to amyl alcohol used was 2: 5. Reaction was run at constant temperature in a three-neck flask as a batch reactor. The acetic acid and sulfuric acid were first put into the reactor and heated while stirring. After reaching a certain temperature, the preheated amyl alcohol was added into the reactor. During reaction, the temperature was maintained at the desired temperature. The reactants and products involved in this reaction were immiscible. The product phases were separated and then the remaining acetic acid content in the water-soluble phase was analyzed by volumetric method. The study was carried out in 4 variations of temperature i.e. 70, 80, 90, and 100 ^oC. The results of experimental data analysis showed that the reaction will be faster when the temperature is higher. The mass transfer from the acetic acid phase to the amyl alcohol phase increased with the increase of temperature. The value of the reaction rate constant, the overall mass transfer coefficient, and the Henry’s constant were evaluated by the parameter fitting method using the MATLAB program. Based on the evaluation at the highest reaction temperature 100 ^oC, the rate constant was 0.0134 mL.mole-2s-1, the mass transfer coefficient was 0.3180 L s-1, and the Henry’s constant was 0.0174 (mole/L)A in phase II/(mole/L)A in phase I.

Keywords: esterification, immiscible, amyl acetate, mass transfer

ABSTRAK

Senyawa ester banyak dipakai sebagai solven, bahan aroma buatan, dan prekursor bahan-bahan farmasi. Salah satu senyawa ester yang banyak digunakan dalam industri kimia dalah amil asetat. Ester amil asetat dapat disintesis melalui reaksi esterifikasi dengan bahan baku amil alkohol dan asam asetat. Reaksi ini merupakan reaksi heterogen cair-cair. Penelitian ini bertujuan untuk mempelajari kinetika reaksi tersebut, terutama pengaruh variabel suhu. Untuk mempercepat laju reaksi ditambahkan asam sulfat. Perbandingan mol pereaksi asam asetat:amil alkohol yang digunakan sebesar 2:5. Reaksi dijalankan dalam reaktor batch dan suhu dijaga konstan. Reaktan dan katalisator dicampur dalam labu leher tiga. Asam asetat dan asam sulfat dituangkan ke dalam reaktor, dipanaskan dan diaduk sampai suhu tertentu. Selanjutnya amil alkohol yang telah dipanaskan sebelumnya hingga suhu tertentu dituangkan. Selama reaksi suhu dipertahankan konstan. Reaktan dan produk yang terlibat dalam reaksi ini berupa campuran immiscible. Produk yang terdiri dari dua fase dipisahkan antar fasenya kemudian fase yang larut dalam air dianalisis kadar asam asetat sisanya dengan metode volumetri. Reaksi dilakukan masing-masing pada suhu 70, 80, 90, dan 100 ^oC. Hasil analisis menunjukkan bahwa reaksi akan semakin cepat apabila suhu semakin tinggi. Transfer massa dari fase asam asetat ke fase amil alkohol semakin besar pula dengan adanya kenaikan suhu. Nilai konstanta kecepatan reaksi, koefisien transfer massa overall, dan konstanta Henry dievaluasi dengan metode fitting parameter menggunakan program MATLAB. Berdasarkan evaluasi pada suhu reaksi tertinggi yaitu 100 ^oC diperoleh nilai konstanta kecepatan reaksi sebesar 0,0134 mL.mol-2s-1, koefisien transfer massa overall sebesar 0,318 mL s-1, dan konstanta Henry sebesar 0,0174 (mol/L)A di fase II/(mol/L)A di fase I.

Kata kunci: esterifikasi, immiscible, amil asetat, transfer massa