Synthesis of N-benzylarylamine derivatives and diphenyl esters of α-aminomethanephosphonic acids and examination of their antioxidant properties

Article abstract of DOI:10.1134/S0965544111060119

A number of new derivatives of N-benzylarylamines and diphenyl α-aminomethanephosphonates have been synthesized, and their structure has been established by IR and ¹H NMR spectroscopy. It has been shown that these compounds can be used as effec

Full text of DOI:10.1134/S0965544111060119

ISSN 0965ꢀ5441, Petroleum Chemistry, 2011, Vol. 51, No. 6, pp. 465–468. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © A.K. Kyazimꢀzade, A.A. Gadirov, 2011, published in Neftekhimiya, 2011, Vol. 51, No. 6, pp. 473–476.
Synthesis of
of
NꢀBenzylarylamine Derivatives and Diphenyl Esters
ꢀAminomethanephosphonic Acids and Examination
α
of Their Antioxidant Properties
A. K. Kyazimꢀzade and A. A. Gadirov
Kuliev Institute of Chemistry of Additives, National Academy of Sciences of Azerbaijan, Baku, Azerbaijan
eꢀmail: gadirov.58@mail.ru
Received June 3, 2011
Abstract—A number of new derivatives of Nꢀbenzylarylamines and diphenyl αꢀaminomethanephosphonates
have been synthesized, and their structure has been established by IR and 1H NMR spectroscopy. It has been
shown that these compounds can be used as effective additives enhancing the thermooxidative stability of
esterꢀbased oils.
DOI: 10.1134/S0965544111060119
Organic compounds containing the secondary duced into a pentaerythritol ester of С5⎯С9 synthetic
nitrogen atom in combination with various heteroatꢀ fatty acids (PEE) for a concentration of 0.5%.
oms and functional groups are widely used as additives
for lubricating oils [1].
The IR spectra of the compounds were recorded on
a Spekord Mꢀ80 spectrometer as a white oil mull
(measurement range, 400–4000 cm–1). Their
1H NMR spectra were recorded on a Brüker ACꢀ300
instrument (operating frequency SFꢀ300, 13 mHz) in
DMSOꢀd6 solutions with HMDS as an internal stanꢀ
dard.
In this work, aimed at finding effective antioxidants
for esterꢀbased oils, we synthesized and studied new
derivatives of Nꢀbenzylarylamines and diphenyl esters
of
αꢀaminomethanephosphonic acids.
The reactants diphenyl phosphite [2],
mꢀnonyꢀ
EXPERIMENTAL
loxyꢀ and ꢀphenyloxybenzaledehydes [3], and correꢀ
p
sponding azomethines [4] were prepared according to
the conventional procedures.
The compounds of interest were synthesized
according to the following schemes:
General Nꢀbenzylarylamines (I–III) synthesis proꢀ
cedure. Sodium borohydride in an amount of 0.11 mol
of was gradually added to a stirred solution of 0.1 mol
of azomethine in dimethylformamide. The reaction
mixture was stirred for 3 h at a temperature of 40–
R'
+ NaBH
4
NH
CH2
R
R'
(I–III)
R N CH
45°С. After cooling, the mixture was poured into 1 l of
water and precipitated crystals were filtered off and
crystallized from ethyl alcohol.
R'
+ (C H O) P(O)H R
(C6H5O)2P
6
5
2
NH CH
General procedure for synthesis of diphenyl αꢀamiꢀ
nomethanephosphonate derivatives (IV–VII). Dipheꢀ
nyl phosphite in an amount of 2.34 g (0.01 mol) was
added to a solution of 0.1 mol of azomethine in 5–
10 ml of ethanol, and the reaction mixture was stirred
at room temperature. Then, the mixture was heated at
60°C over a water bath for 1 h. The product was recrysꢀ
tallized from a 1 : 1 benzene–ethanol mixture, washed
with hexane, and dried.
O
(IV–VII)
R =
R' =
R =
α
p
ꢀC10H7ꢀ, R' =
ꢀHOꢀ (II); R = C6H5ꢀ, R'= C6H5(CH2)2O (III);
СН3ОС6Н4ꢀ, R' = СН3Оꢀ (IV); R =
C6H5CH2ꢀ, R' = ꢀF (V); R = C6H5ꢀ, R' = С9Н19Оꢀ
(VI); R = НОС6Н4ꢀ, R' = С9Н19Оꢀ (VII).
mꢀС9Н19Оꢀ (I); R = (C6H5)2CHꢀ,
pꢀ
pꢀ
p
mꢀ
oꢀ
mꢀ
The antioxidant activity of the newly synthesized
compounds was determined according to GOST
(USSR State Standard) 23797ꢀ79. Testing was conꢀ
RESULTS AND DISCUSSION
The composition of compounds I–VII was deterꢀ
ducted for 20 h at 225°С in the presence of steel, copꢀ mined on the basis of elemental analysis data, and
per, and aluminum plates. The additives were introꢀ their structure was confirmed by IR and NMR specꢀ
465

466
KYAZIMꢀZADE, GADIROV
Table 1. Physicochemical characteristics and elemental analysis data for the compounds
Found, %
Compound
notation
Empirical
formula
Yield
%
,
Compound
Mp, °C
Calculated, %
N
P
C
H
I
Nꢀ(mꢀNonyloxybenzyl)ꢀαꢀnaphthyꢀ
lamine
C H NO
72
90
74
82–84 3.56
3.73
–
83.40 8.78
83.15 8.86
26 33
II
Nꢀ(pꢀHydroxybenzyl)diphenylmethyꢀ C H NO
lamine
91–93 4.98
4.98
–
–
82.83 6.48
83.01 6.62
20 19
III
IV
Nꢀ(pꢀPhenylethoxybenzyl)aniline
C H NO
67–69 4.54
4.62
82.94 6.79
83.13 6.98
21 21
Diphenyl ester of αꢀ[(pꢀmethoxyphenylꢀ C H NPO
amino)ꢀp'ꢀmethoxyphenylꢀ
methane]phosphonic acid
85 115–117 3.12 6.43 67.93 5.57
2.95 6.52 68.20 5.51
27 26
5
V
Diphenyl ester of αꢀ[(benzylamino)ꢀpꢀ C H NPO F
fluorophenylmethane]phosphonic acid
65
98–100 3.24 6.78 69.60 5.32
3.13 6.92 69.79 5.18
26 23
3
VI
Diphenyl ester of αꢀ[(phenylamino)ꢀmꢀ C H NPO
nonyloxyphenylmethane]phosphonic
acid
80 105–107 2.66 5.37 73.45 7.05
2.51 5.55 73.22 7.23
30 40
4
VII
Diphenyl ester of αꢀ[(oꢀhydroxyphenyꢀ C H NPO
lamino)ꢀm'ꢀnonyloxyphenylꢀ
methane]phosphonic acid.
78 114–116 2.21 5.15 71.35 7.18
2.24 5.40 71.18 7.03
34 40
5
troscopy. The physicochemical characteristics of the (3300–3400 cm–1), P=O (1250–1280 cm–1), and
compounds are given in Table 1.
The IR spectra of these
P
⎯
O–C (1190–1240 cm–1) groups.
The 1H NMR spectrum of diphenyl
Nꢀbenzylarylamines do not
α
ꢀ(4ꢀmethoxyꢀ
exhibit absorption bands at 1615–1670 cm–1 correꢀ
sponding to stretching vibrations of the –CH=N
group and display a distinct band at 3300–3400 cm–1
due to stretching vibrations of the NH group.
phenylamino)ꢀ4'ꢀmethoxyphenylmethanephosphonate
displays proton signals ( , ppm) due to the following
groups: 7.58 d (2H, А(о)
= 9.9 Hz), 7.33 m (2H,
C(m), 7.18 t (2H, C(p), = 7.0 Hz), 7.10 d (2H, A(m)
= 9.0 Hz), 6.88 m (6H, C(o) and B(o)), 6.68 d (2H,
B(m)
= 9.0 Hz), 6.32 dd (1H, >NH, JCH
10.8 Hz, JP
δ
,
J
J
,
The 1H NMR spectrum of
N mꢀnonyloxybenzyl)ꢀ
ꢀ(
ꢀnaphthylamine exhibits proton signals attributed to
the following groups ( ): the chemical shifts at 4.45
and 0.9 ppm to the СН2⎯ and СН3 groups and the
singlet at 1.3 ppm and the triplet at 3.9 ppm to the
(СН2)6⎯ and СН2⎯ moieties, respectively. Aroꢀ
J
,
J
=
NH
⎯NH,
α
NH = 5.5 Hz), 5.42 dd (1H, CH⎯
= 25.C7HHz, JCH
= 10.8 Hz), 3.72 s (3H,
OCCHH3 from B), 3.60 sN(3HH,
OCH3 from A) (comꢀ
pound IV, Fig. 2).
δ
⎯
⎯
JP
⎯
⎯
N⎯
⎯
⎯
⎯
⎯
⎯О⎯
matic protons are displayed as multiplets in the region
of 6.35–7.45 ppm (compound I, Fig. 1).
Table 2 presents the results of comparative testing
of the synthesized compounds and the commercial
The IR spectra of diphenyl esters of
αꢀamiꢀ additive phenylꢀαꢀnaphthylamine (FAN). The comꢀ
nomethanephosphonic acids (IV–VII) display pounds are superior to the known inhibitor FAN in all
absorption bands due to the presence of the NH parameters that characterize the extent of oxidation of
PETROLEUM CHEMISTRY Vol. 51
No. 6
2011

SYNTHESIS OF
N
ꢀBENZYLARYLAMINE DERIVATIVES AND DIPHENYL ESTERS
467
(CH2)6
O
N
рꢀsolvent
CH3
СН2О
NCH2
N
NH
8.5 8.0 7.5 7.0
6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5
1.0
5
1
Fig. 1. H NMR spectrum of
Nꢀ(
m
ꢀnonyloxybenzyl)ꢀ
α
ꢀnaphthylamine.
synthetic oil (acid number, kinematic viscosity,
The highest performance under the given testing
amount of sediment). There was no corrosion of the conditions was shown by compounds I and VII, which
metal plates.
contain the nitrogen atom in combination with the
(A)
)
(B)
(
m
(
o
)
(m)
(o)
HA HX
C*
N
OCH3
CH3O
–OCH3 –OCH3
(o)
(m)
(p)
O
P O
2
(о)
(о)
В
and
С
(C)
(m)
В
[(CD ) SO]
3 2
(m)
С
(m)
А
(p)
С
CH–NH
NH
7.4
7.2
7.0 6.9
6.7
6.5
6.3
6.0 5.9
5.7
5.5 5.4 4.0
3.8 3.7 3.6
δ
, m
1
Fig. 2. H NMR spectrum of diphenyl ester of
α
ꢀ[(benzylamino)ꢀp'ꢀfluorophenylmethane]phosphonic acid.
PETROLEUM CHEMISTRY Vol. 51
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2011

468
KYAZIMꢀZADE, GADIROV
Table 2. Effect of the compounds on the thermooxidative stability of pentaerythritol ester at 225°C for 20 h
After oxidation
Kinematic viscosity, mm2/s
No.
Additive
Amount
of sediment, %
Acid number, mg
KOH/g
at 100°C
at –40°С
1
2
3
4
5
6
7
8
9
PEE
*
0.15
0.2
7.6
4.8
1.4
2.3
2.8
2.4
2.3
2.2
1.6
7.2
38000
28000
20800
21000
25200
25350
22000
21700
20620
Phenyl
ꢀα
ꢀnaphthylamine
6.45
5.3
5.1
5.5
5.6
5.4
5.2
I
0.07
0.11
0.18
0.16
0.18
0.12
0.05
II
III
IV
V
VI
VII
5.15
2
* The oil before oxidation had an acid number of 0.4 mg KOH/g and viscosity values of 5.1 mm /s and 9850 mm at 100 and –40
respectively.
°C,
longꢀchain nonyloxy group. For example, when these
compounds were added in an amount of 0.5 wt % to
pentaerythritol ester, the kinematic viscosity at ⎯40°С
REFERENCES
1. A. M. Kuliev, Chemistry and Technology of Oil and Fuel
Additives (Khimiya, Leningrad, 1985) [in Russian].
was 20620–20800 mm2/s and the acid number was
1.4–1.6 mg KOH/g, whereas the application of FAN
with the same concentration makes these quantities to
be 28000 mm2/s and 4.8 mg KOH/g, respectively.
Compounds II–VI also exhibit good antioxidant
properties and do not rank below FAN in perforꢀ
mance. Thus, the results allow us to categorize these
compounds with promising ester oils capable of operꢀ
2. M. P. Fieser, Fieser’s Reagents for Organic Synthesis
,
(Wiley, New York, 1979), vol. 7.
3. G. Hilgetag and A. Martini, Weygand–Hilgetag orgaꢀ
nischꢀchemische Experimentierkunst (Johann Ambroꢀ
sius Barth: Leipzig, 1964; Khimiya, Moscow, 1968),
3rd ed. p. 944.
4. Yu. A. Bruk, F. Yu. Rachinskii, L. V. Zolotova, et al.,
ating at 225°С.
Zh. Obshch. Khim. 42 (1972).
PETROLEUM CHEMISTRY Vol. 51
No. 6
2011