Journal of Chemistry
3
magnesium sulphate for 24 hours, and then we filtered and
carried out a fractionated distillation of the solvent under
reduced pressure, b.p. about 40∘C/400 mmHg, to give 4-[(6-
hydroxyhexyl)oxy]-2,5-dimethylbenzonitrile, a light brown
oil [10, 12]. From the obtained mass, the volume was cal-
culated using the approximate density of the compound,
1.33 g⋅mL−1, and had a yield of about 30%.
OH
OH
CuCN
I
NC
Scheme 3: Synthesis of 4-hydroxy-2,5-dimethylbenzonitrile.
2.4. Synthesis of 4-[(6-Bromohexyl)oxy]-2,5-dimetilbenzoni-
trile. For this synthesis, Scheme 5 was adapted from the
hydrobromic acid’s method described by [13], where the
procedure was applied for the preparation of 4-[(6-bro-
mohexyl)oxy]-2,5-dimetilbenzonitrile from 4-[(6-hydroxy-
hexyl)oxy]-2,5-dimetilbenzonitrile. In a 25 mL flask 0.50 mL
of concentrated sulphuric acid was slowly dissolved in
0.80 mL of 48% hydrobromic acid under stirring and exter-
nal cooling. 1.5 mL of 4-[(6-hydroxyhexyl)oxy]-2,5-dimetil-
benzonitrile was added then portion wise we added over
0.35 mL of concentrated sulphuric acid [12].
subjected to fractional distillation under reduced pressure,
b.p. about 40∘C/400 mmHg [10]. e product, 4-iodo-2,5-
dimethylphenol, had a yield of 75% and the melting point of
the crystals was approximately 90∘C.
2.2. Synthesis of 4-Hydroxy-2,5-dimethylbenzonitrile. In the
synthesis of Scheme 3, 0.02 moles of 4-iodo-2,5-dimethyl-
phenol obtained above was also employed and was dissolved
in 20 mL of N, N-dimethylformamide (DMF) and the mix-
ture brought to an addition funnel. An equivalent amount in
moles plus 10% copper cyanide was also dissolved in 20 mL
of DMF and added to a three-way flask [8, 9].
e system has been mounted in which a flask inputs
received the dropping funnel; the other was connected to
a condenser and the third way is closed. With the aid of
magnetic stirrer and heater it started heating. With the
beginning of reflux the entire solution was dripped slowly in
the dropping funnel. Afer complete addition, the solution
was refluxed continuously for another 6 hours [9]. Afer
time of reflux, the solution was allowed to reach room
temperature and was added to 40 mL of a saturated solution
of ethylenediaminetetraacetic EDTA, which was allowed to
stir for 24 hours.
Afer this stage, the solution was cooled down to obtain
better crystals and then filtered. For purification the product
was performed chemically active with an extraction solvent,
where it is first dissolved in chloroform and we transferred
the entire contents to a separating funnel, which underwent
five washes with 5% sodium hydroxide. When obtaining an
aqueous extract it was adjusted to pH 7.0 with drops of
concentrated hydrochloric acid to obtain a precipitate which
is filtered and dried in a vacuum desiccator [9, 11]. e
product was obtained in a yield of 35%, and its melting point
was 121∘C.
e system was allowed to warm to 30∘C for 2 hours and
formed two phases. We moved the cooled reaction mixture
to a separatory funnel, separated the organic phase, washed
it with 20 mL 10% hydrochloric acid, 20 mL of distilled
water, and 10 mL of an aqueous solution of 5% sodium
hydroxide, and finally we washed it again with 20 mL of
distilled water. e dry organic phase was extracted with
anhydrous magnesium sulphate during a time of 24 hours.
With filtration of the dried product directly to a 25 mL
flask and held fractional distillation under reduced pressure,
b.p. about 40∘C/400 mmHg, the yield was approximately
85%.
In addition to the techniques FTIR and NMR this
reaction was characterized by GC-MS to verify the change of
the hydroxyl group by bromine.
e solid obtained was dissolved in appropriated solvent
at room temperature. An appropriate solution volume was
injected into the chromatographer with a microsyringe.
GC-MS was performed in a Shimadzu gas chromatograph
coupled with a mass selective detector model QP2000A.
A 60 m long and 0.25 mm diameter SE-30 GC capillary
column coated with poly(dimethyl siloxane) was used and the
appropriate solution was injected at 80∘C. Column tempera-
ture was programmed to remain at 40∘C for 6 min and then
raised to 150∘C at a heating rate of 10∘C min−1. Helium was
used as a carrier gas at a flow rate of 30 mL min−1.
2.3. Synthesis of 4-[(6-Hydroxyhexyl)oxy]-2,5-dimetilbenzoni-
trile. e synthesis of Scheme 4 followed the method
described by Chang et al. [10], where compound was prepared
by alkylation of 4-hydroxy-2,5-dimethylbenzonitrile with 6-
chlorohexan-1-ol. A solution of 0.01 moles of 4-hydroxy-2,5-
dimethylbenzonitrile, 0.015 moles of potassium hydroxide,
and 0.00105 moles of tetrabutylammonium bromide in 20 mL
of distilled water was stirred at room temperature for 15
minutes. Subsequently we slowly added 0.01 moles of 6-
clorohexan-1-ol [10].
e reaction proceeded with stirring and reflux for 22
hours. Afer complete reaction the product was extracted
with 30 mL of chloroform. is organic phase was washed
with a sodium hydroxide solution of 10% and boiling water
successively. Dry the resulting organic layer with anhydrous
3. Results and Discussion
3.1. Characterization of 4-Iodo-2,5-dimethylphenol. In the
reaction described for obtaining 4-iodo-2,5-dimethylphenol,
it is necessary basic medium to occur, NaOH, because the
presence of the base has the function to remove a proton from
the hydroxyl group present in the compound 2,5-dimethyl-
phenol, thereby forming an activating group ortho-para more
reactive than phenol, which makes entry iodine atom in the
para position favorable with respect to the hydroxyl group.
As to attack of the electrophilic compound, it is generated in
situ in the reaction medium by the reaction of sodium iodide