Sintesis 1,4-dibenziloksi butana dan 1,4-butilen glikol dibenzoat untuk komponen elektroda selektif ion ammonium
WIBOWO, Atmanto Heru, Dr. Dwi Siswanta, MEng
2001 | Tesis | S2 KimiaTelah dilakukan sintesis 1,4-dibenziloksi butana untuk plasticizer ESI-N€-€,+d an 1,4-butilen glikol dibenzoat untuk ionofor ESI-NH,+. 1,4- Dibenziloksi butana disiqtesis dari benzil klorida dan 1,4-butanadiolY sedangkan 1 ,4-butilen glikol dibenzoat disintesis dari benzoil klorida dan 1~4-butanadiol. Analisis dua produk tersebut dilakukan dengan GC, 'H NMR, IR, dan GC-MS. Komposisi membran uji yang dibuat adalah 3% b/b ionofor + 66% b/b plasticizer + 1% b/b kalium tetrakis (p-klorofenil) borat (KTCPB).K arakterisasi plasticizer 1,4-dibenziloksi butana dilakukan dengan mengukur selektivitas, faktor Nernst, dan waktu responnya dengan ataupun tanpa penambahan ionofor 1,4-butilen glikol dibenzoat. Karakterisasi yang sama juga dilakukan terhadap ionofor 1,4-butilen glikol dibenzoai dengan menggunakan plasticizer 1,4-dibenziloksi butana dan orto-nitrofenil oktileter (0-WOE). Di dalam penelitian ini juga dipelajari penggunaan asam oleat sebagai aditif pengganti KTCPB untuk ESI-NH,+ dan asam benzoat sebagai katalis transfer kationik sampel. Hasil penelitian menunjukkan bahwa plasticizer 1 ,4-dibenziloksi butana dengan ataupun tanpa adanya 1,4-butilen glikol dibenzoat memberikan selektivitas ammonium terhadap kalium ( log KEi vK+) sebesar -1,z. Hasil ini juga menunjukkan bahwa 1,4-butilen glikol dibenzoat memberiknn selektivitas ammonium lebih tinggi terhadap kalium di dalam plasticizer 1,4-dibenziloksi butana untuk ESI-NH4+. Hasil sebaliknya, selektiviias ammonium lebih rendah terhadap kalium (log Kz:,,, = 0,41) diperoleh apabila 1,4-butilen glikol dibenzoat di dalam plasticizer o-WOE. Ionofor 1 +butilen glikol dibenzoat mendukung plasticizer 1 ,4-dibenziloksi butana untuk ESI-NH4+ dengan meningkatkan faktor Nernst dari 54,8 menjadi 58,O mV perdekade. Ionofor 1,4-butilen glikol dibenzoat di dalam plasticizer o-NPOE menunjukkan faktor Nernst sebesar 53,3 mV perdekade untuk ESI-K+. Hasil uji membran juga menunjukkan bahwa asam oleat tidak dapat digunakan sebagai pengganti KTCPB, karena mempunyai selektivitas ammonium yang rendah terhadap kalium ( logKEri,j > -1 ) untuk ESI-NH4+. Walaupun aditif asam benzoat dapat meningkatkan faktor Nernst ESI-NH4+ dan ESI-K+, akan tetapi lipofilisitas asam benzoat yang reridah (log pChemp=r o2 ,03) merupakan hambatan dalam penggunaan aditif asam ini untuk katalis transfer kationik sampel.
1,4-Dibenzyloxy butane and 1 ,4-butylene glycol dibenzoic were synthesized and used as plasticizer and ionophores for a m4+-ISE, respectively. 1,4-Dibenziloxy butane was synthesized by adding benzyl chloride to 1,4-butanediol. The same procedure was also applied to the synthesis of 1,4-butylene glycol dibenzoic by changing benzyl chloride with benzoyl chloride. The products were identified by GC, IR, 'H NMR, and GCMS. The membrane composition examined in this study was 3% wlw ionophores + 66% w/w plasticizer + 1% w/w pottasium tetrakis @- chlorophenyl) borate (KTCPB). Characterizations of 1,4-dibenzyloxy butane as plasticizer in the presence and absence of 1,4-butylene glycol dibenzoic were done by measurements of its selectivity, Nernst factor, and response time for N€&+-ISEC. haracterizations of 1,4-butylene glycol dibenzoic were carried out using both 1,4-dibenzyloxy butane and ortho-nitrophenyl oktylether (0-WOE) as plasticizers. The possible application of oleic acid for alternative additive to replace pottasium tetrakis @-chlorophenyl) borate (KTCPB) as well as of benzoic acid for cationic-transfer catalyst in selectiveelectrode membrane was also investigated. Experimental results showed that for a NH4+-ISE, 1,4-dibenzyloxy butane in the presence and absence of 1,4-butylene glycol dibenzoic ionophores exhibited about -1.2 ammonium selectivity over pottasium ( log KEi,K, ). The results also indicated that 1,4-butylene glycol dibenzoic ionophores incoorporated in 1,4-dibenzyloxy butane plasticizer had higher selectivity towards ammonium over kalium ( ~ O ~ K E ;=,-~1,,2 ). In case o- WOE was utilized as plasticizer for a m,+-ISE, it exhibited higher selectivity towards pottasium over ammonium. It was also found that 1,4- butylene glycol dibenzoic supported 1,4-dibenzyloxy butane plasticizer by increasing Nernst factor from 54.9 to 58.0 mV perdecade for a NH,+-ISE. The same compound exhibited 53,3 mV perdecade when it was incoorporated in o-WOE for a K+-ISE. Oleic acid induced low ammonium selectivity over pottasium ( logKgi,j > -1 ) when it was utilized as additive for a NH,+-ISE to replace KTCPB. This result suggested that oleic acid was not an effective compound for additive purpose. In addition, although benzoic acid could enhance Nernst factor for both a NH4+-ISE and a K+-ISE, the lack of its lipophilicity restricted its usage for a sample-cationictransfering catalyst.
Kata Kunci : Ion Ammonium,Esi Ammonium
