Effect of reaction variables on the overall yield of 1,4-Di-n-alkylbenzenes

1,4-di-n-hydroxylalkylbenzenes were obtained from terephthalaldehyde and the appropriate n-alkylbromide through Grignard reaction. These starting compounds were converted either to the corresponding 1,4-di-n-alkanoylbenzenes via oxidation or to the corresponding 1,4-di-n-alkenylbenzenes via dehydration. Both the oxidation and the dehydration products were hydrogenated to give the corresponding 1,4-di-n-alkylbenzenes. Oxidation step was carried out using CrO 3 at 50°C and the dehydration step was performed using anhydrous CuSo 4 at 165-170°C. Hydrogenation step was catalyzed by Pd/C or Pt/C at a temperature range 40-120°C and 50 psi H 2 pressure in presence of acetic acid. Over Pd/C hydrogenation yields were found to reach 76.0, 76.8, 76.6, 79.2 and 79.7 wt% based on feed for 1,4-di-n-butyl-, 1,4-di-n-pentyl, 1,4-di-n-octylbenzene respectively. Effects of hydrogenation variables on yield were investigated. IR, NMR and Mass spectroscopy were carried out to confirm the structure.