REAKSI-REAKSI PENDAHULUAN
REAKSI-REAKSI PENDAHULUAN
GOLONGAN ALKALOIDPRINSIP DAN REAKSIGolongan fenol adalah senyawa
yang memiliki paling tidak satu gugus hidroksil yang terikat pada
rantai alifatik.
Prinsip reaksi identifikasi untuk golongan alkohol
Reaksi esterfikasi terbentuk ester yang dapat diamati dari
aromanya.
BAHAN DAN ALAT
Pelat tetes, tabung reaksi, penjepit kayu, pembakar bunsen
Sampel etanol, gliserin, mentol,
Etanol (CH3CH2OH) BM 46,07 Titik didih 78oC
Cairan tidak berwarna, jernih, higroskopik, mudah terbakar,
mudah menguap. PROSEDUR
1. Menggunakan tabung reaksi, masukkan 1 ml etanol. Tambahkan
asam salisilat atau asam benzoat, kemudian perlahan-lahan melalui
dinding tabung, tambahkan H2SO4. Tutup mulut tabung dengan sumbat
kapas. Panaskan di atas penangas air. Amati aroma pada penutup
kapas.
2. Menggunakan tabung reaski, Lakukan reaksi iodoform. Amati
aroma hasil reaksi
3. Menggunakan tabung reaksi, tambahkan larutan jenuh K2Cr2O7
jenuh dalam H2SO4 50%. Amati perubahan yang terjadi.
PENGAMATAN
NOREAGENSIAPENGAMATAN
1Esterfikasi
2Iodoform
3K2Cr2O7
REAKSI
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Gliserin (C3H8O3) BM 92,05 Jarak lebur 0-20oC
Cairan yang tidak berwarna, kental, dan berasa manis.
Struktur kimia gliserol
PROSEDUR
1. Campurkan larutan gliserin dengan 1 tetes CuSO4 dan basakan
dengan NaOH. Amati perubahan warna yang terjadi.
PENGAMATAN
NOREAGENSIAPENGAMATAN
1CuSO4 + NaOH
2
3
REAKSI
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Mentol (C10H20O) BM 156,27 Jarak lebur 43-44oC
Serbuk kristal putih, aroma pepermin, rasa dingin.
Struktur Kimia Mentol
PROSEDUR
1. Letakkan mentol di atas pelat tetes. Amati aromanya.
2. Menggunakan pelat tetes, tambahkan H2SO4 dan salisilaldehid.
Amati perubahan warna yang terjadi.
PENGAMATAN
NOREAGENSIAPENGAMATAN
1
2
3
4
REAKSI
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Resorsinol (C6H6O2) BM 110,1 Jarak lebur 109-112oC
Serbuk kristal putih, menjadi merah jika terkena cahaya.
PROSEDURPENGAMATAN
NOREAGENSIAPENGAMATAN
1p-DAB
2FeCl3
3Lieberman
4Ag(NH3)NO3
REAKSI
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