THE INFLUENCE OF NITRO GROUP ON SYNTHESIS OF THE AZO COMPOUND DERIVATIVES FROM VANILLIN AS AN ACID-BASE INDICATOR AND ANION SENSORS

Tini Kaimudin, Dr. Bambang Purwono, M.Sc.

2011 | Tesis | S2 Ilmu Kimia

Telah diteliti pengaruh gugus nitro pada sintesis turunan senyawa azo dari vanilin 4-hidroksi-3-metoksi-5-(fenildiazenil)benzaldehida dan 4-hidroksi-3- metoksi-5-(p-nitrofenildiazenil)benzaldehida sebagai senyawa indikator asam-basa dan sensor anion. Sintesis senyawa 4-hidroksi-3-metoksi-5-(fenildiazenil)- benzaldehida dilakukan dengan mereaksikan garam benzenadiazonium klorida dengan vanilin dalam larutan natrium hidroksida dan diperoleh randemen 40,28%. Garam p-nitrobenzenadiazonium klorida direaksikan dengan vanilin dalam larutan natrium hidroksida menghasilkan senyawa 4-hidroksi-3-metoksi-5-(pnitrofenildiazenil) benzaldehida dengan hasil 53,64%. Hasil uji sebagai senyawa halochromic dan acidichromic menunjukkan bahwa senyawa 4-hidroksi-3-metoksi5-( p-nitrofenildiazenil)benzaldehida memberikan perubahan warna lebih tajam daripada senyawa 4-hidroksi-3-metoksi-5-(fenildiazenil)benzaldehida. Senyawa 4- hidroksi-3-metoksi-5-(fenildiazenil)benzaldehida dan 4-hidroksi-3-metoksi-5-(pnitrofenil- diazenil)benzaldehida dapat digunakan sebagai indikator titrasi asam lemah-basa kuat. Senyawa 4-hidroksi-3-metoksi-5-(fenildiazenil)benzaldehida dapat digunakan sebagai sensor anion sianida dengan limit deteksi 1000 ppm, sedangkan senyawa 4-hidroksi-3-metoksi-5-(p-nitrofenildiazenil)benzaldehida dapat mendeteksi anion fluorida dengan limit deteksi 25 ppm dan anion sianida pada 0,5 ppm.

It has been researched the influence of nitro group on synthesis of the azo compound derivatives from vanillin 4-hydroxy-3-methoxy-5-(phenyldiazenil) benzaldehyde and 4-hydroxy-3-methoxy-5-(p-nitrophenyldiazenil) benzaldehyde as an indicator of acid-base and anion sensors compounds. Synthesis of 4-hydroxy-3- methoxy-5-(phenyldiazenil) benzaldehyde was carried out by reacting of benzenediazonium chloride salt with vanillin in sodium hydroxide solution and gave 40.28% yield. p-Nitrobenzenediazonium chloride salt reacted with vanillin in sodium hydroxide solution produced 4-hydroxy-3-methoxy-5-(p-nitrophenyldiazenil) benzaldehyde with 56.64% yield. The test results as halochromic and acidichromic compounds showed that the 4-hydroxy-3-methoxy-5-(p-nitrophenyldiazenil) benzaldehyde produced color changes more sharply than 4-hydroxy-3-methoxy-5- (phenyldiazenil) benzaldehyde. The 4-hydroxy-3-methoxy-5-(phenyldiazenil) benzaldehyde and 4-hydroxy-3-methoxy-5-(p-nitrophenyldiazenil) benzaldehyde can be used as an indicator titration of weak acid-strong base. The 4-hydroxy-3-methoxy5-( phenyldiazenil) benzaldehyde can also be used as a cyanide anion sensor with a detection limit of 1000 ppm, while 4-hydroxy-3-methoxy-5-(p-nitrophenyldiazenil) benzaldehyde can detect fluoride and cyanide anions with detection limits of 25 ppm and 0.5 ppm respectively.

Kata Kunci : vanilin, gugus nitro, indikator asam-basa, sensor anion, 4-hidroksi-3- metoksi-5-(fenildiazenil)benzaldehida, 4-hidroksi-3-metoksi-5- (p-nitrofenildiazenil)benzaldehida