NMR spectrum of benzyl alcohol:
You may note that as the temperature is lowered from 31oC to 6oC and then to 1oC
no splitting occurs in any of the two lines though both lines get
broadened; the broadening in OH signal being more prominent. On further
lowering the temperature down to -4oC broadening becomes more significant suggesting some kind of interaction which, however, becomes clear at - 6oC. At -14oC,
methyl group signal shows a doublet (J = 5.2 Hz) due to spin-spin
interaction with OH proton. At the same time OH signal also shows a
doublet but with some structure on both sides. On further lowering of
temperature to -40oC, a clear quartet (J = 5.2 Hz) is observed for the hydroxyl proton.
This kind of observation can be
explained in terms of chemical exchange. The observed spectra indicate
that at room temperature rate of chemical exchange is very fast giving
rise to two sharp singlets. However, at - 40oC, rate of chemical exchange is very slow giving rise to multiplets arising out of spin-spin coupling.
Benzyl alcohol: In order to understand
the effect of benzene ring in alcohols, let us take the example of
benzyl alcohol. The spectrum of benzyl alcohol recorded at 60 MHz is
shown in Figure. In the two cases discussed above you have seen that OH
signal is observed at down fields due to O atom being electronegative.
However, in the case of C6H5CH2OH, the OH signal is observed quite upfield (δ = 2.5 ppm) and the benzyl group downfield (δ = 7.2 ppm) with methylene group (-CH2-)
in between the two (δ = 4.6 ppm). You know that the downfield shift of
benzyl group protons is due to the anisotropic effect of the benzene
ring. In none of these cases, however, any multiplicity is observed.
Figure: NMR spectrum of benzyl alcohol (C6H5CH2OH) in CCl4 at low resolution
.
pandharpur, maharashtra, india
Pandharpur - Wikipedia, the free encyclopedia
en.wikipedia.org/wiki/Pandharpur
Pandharpur is a pilgrimage city on the banks of Bhimā river in Solāpur district, Maharashtra, India. Pandharpur is situated on the 1711 north axis and the 7511 ...
alandi pandharpur ashadi wari food preparation
Pandharpur is an important pilgrimage city on the banks of Bhimariver in
Solapur district, Maharashtra. Pandharpur is situated on the 1711 north
axis and 7511 the east longitude in Solapur District.
Akkalkot was the home to Shri Swami Samarth Maharaj, a 19th century
saint who is believed by his devotees to be an incarnation of God
Dattatreya. Tuljapur, the one amongst three and half Shakti Peethas
(abodes of cosmic powers) of the state, is situated in the Osmanabad
district of Maharashtra
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.pandharpur, maharashtra, india
Pandharpur - Wikipedia, the free encyclopedia
en.wikipedia.org/wiki/Pandharpur
alandi pandharpur ashadi wari food preparation
Pandharpur is an important pilgrimage city on the banks of Bhimariver in
Solapur district, Maharashtra. Pandharpur is situated on the 1711 north
axis and 7511 the east longitude in Solapur District. Akkalkot was the home to Shri Swami Samarth Maharaj, a 19th century saint who is believed by his devotees to be an incarnation of God Dattatreya. Tuljapur, the one amongst three and half Shakti Peethas (abodes of cosmic powers) of the state, is situated in the Osmanabad district of Maharashtra
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