Synthesis of derivatives of alkylamino alkyloxy propanol structures by N-alkylation, acylation, and nitration. Application as fuel additives

Article abstract of DOI:10.1007/s11746-997-0130-0

Polyfunctional compounds were prepared by alkylation, acylation, and nitration of hydroxyl and amine functions of the following alkanolamine ether structures: (di)alkylamino alkyloxy propanol, hydroxy alkyloxy (di)alkylamino propanol, and their dimer comp

Full text of DOI:10.1007/s11746-997-0130-0

Synthesis of Derivatives of Alkylamino Alkyloxy Propanol
Structures by N-alkylation, Acylation, and Nitration.
Application as Fuel Additives
Pascale Satgé de Caro, Zéphirin Mouloungui*, and Antoine Gaset
Ecole Nationale Supérieure de Chimie de Toulouse, Laboratoire de Chimie Agro-Industrielle - UA INRA,
31077 Toulouse Cedex, France
ABSTRACT: Polyfunctional compounds were prepared by
alkylation, acylation, and nitration of hydroxyl and amine func-
tions of the following alkanolamine ether structures: (di)alkyl-
amino alkyloxy propanol, hydroxy alkyloxy (di)alkylamino
propanol, and their dimer compounds. The resulting com-
pounds were characterized by conventional spectroscopic
methods, and complete nuclear magnetic resonance data are
given. These reactions extented the application of these
propanic compounds to use as multipurpose fuel additives. In
particular, they enhance phase stability and improve the cetane
number in ethanol–diesel fuel blends.
JAOCS 74, 241–247 (1997).
KEY WORDS: Alkyloxy alkylamino propanol derivatives,
acylation, ethanol–diesel fuel-additive blends, fuel additive, ig-
nition improvement, N-alkylation, nitration, polyfunctional
compounds, surface-active agent, viscosity.
SCHEME 1
Triglyceride derivatives, such as phospholipids or acyloxy/
aryloxy propanolamines, have been employed in a variety of
biological application (1–4). In the present experiments, we
A number of ethers, esters, phenols, or nitrated compounds
developed other types of polyfunctional propanic compounds have been mentioned as specific fuel additives (6), although
for application as fuel additives.
most of them are not suitable for fuels that contain ethanol.
In a previous study (5), we described the synthesis of the They often have a reduced efficiency in the presence of
following three basic alkanolamine ether structures, the alkyl- ethanol (peroxides, alkyl nitrates) or they are not miscible in
oxy alkylamino propanols (I) and the two dimer structures (II blends with ethanol (polyethylene glycol dinitrates). Further-
and III). These compounds present several active sites on the more, some pro-cetane compounds require careful handling
basic propanic skeleton (Scheme 1).
or can only be synthesized by onorous methods (7).
In the present work, these materials were modified by
The present compounds exhibited good compatibility with
chemical alteration of the –OH and –NH sites by N-alkyla- ethanol–diesel fuel blends. Owing to multiple actions of these
tion, O-acylation, N-acylation, O-nitration, or N-nitration. derivatives, the resulting ternary blend presented good quali-
These novel compounds were prepared in quantitative yield ties to be used in compression ignition engines (8,9).
by a method that could be scaled up for cost-effective produc-
tion. Of significance for use as fuel additives, the C/N and
N/O ratios of the derivatives could be altered, and hydrocar-
EXPERIMENTAL PROCEDURES
bon chains could be added at will by the present method.
Materials. Alkanoyl chlorides (99%) and 3,5-di-tert-butyl-4-
hydroxy benzyl chloride (>98%) were purchased from Lan-
caster (Strasbourg, France). Hydrochloric acid (36%), methyl
iodide (99%), triethylamine (99%), and fuming nitric acid
*
To whom correspondence should be addressed at Ecole Nationale
Supérieure de Chimie de Toulouse, Laboratoire de Chimie Agro-Industrielle
UA INRA nº31A1010 - INPT, 118 route de Narbonne 31077, Toulouse
(
>99.5%) were purchased from Fluka (St. Quentin Fallavier,
-
Cedex, France.
France). Organic solvents (purum for synthesis) were supplied
Copyright © 1997 by AOCS Press
241
JAOCS, Vol. 74, no. 3 (1997)

242
P. SATGÉ DE CARO ET AL.
SCHEME 2
by SDS (Solvants, Documentation, Synthèses; Bordeaux,
NF M07-042 = EN 116 (Ref. 10). Determination of low
France). The reagents were used without further purification.
flow temperature: The fuel blend is made to pass through a
1
Analyses. H nuclear magnetic resonance (NMR) spectra standard filtering device under decreasing temperature.
were recorded on an ARX400 Bruker (Wissenbourg, France)
NF M07-047 = ASTM D 2274/70 (Ref. 10). Stability of
spectrometer (400,134 MHz), in CDCl solvent. Signal posi- diesel fuel: The fuel remains under oxygen bubbling for 16 h
3
tions (δ values) were measured relative to the signal for CHCl
at 95°C. The amount of insoluble materials formed is
δ 7.24). C NMR { H} spectra were recorded on a AC200 weighed.
3
1
3
1
(
Bruker spectrometer (50,323 MHz) with CDCl solvent. The
3
resonance positions were measured relative to the CDCl sig-
3
N-ALKYLATION REACTION BY ALKYL CHLORIDE
1
5
1
nal (δ 77.0). N NMR { H} spectra were recorded on a
AM300 Bruker spectrometer (30,424 MHz). Signal positions This step consisted in linking a specific antioxidative group
δ values) were measured relative to the liquid ammonia sig- to the basic structures. A direct condensation between two al-
(
nal. IR spectra were recorded on a 1600 FT-IR Perkin-Elmer cohol functions or between alcohol and amine functions was
spectrophotometer (Norwalk, CT) with liquid films between prevented by steric hindrance of the functional sites. The ben-
KBr plates. Ultraviolet (UV) spectra were recorded in the zyl alcohol function was first chlorinated under the following
1
90–400 nm region in solution (petroleum ether) with a Vec- conditions (Scheme 2).
tra ES/12 Hewlett-Packard spectrophotometer (Palo Alto, The benzyl chloride 1 was then condensed with the alkyl-
CA). Mass spectra were recorded on a HP5989 Hewlett- oxy propanolamine structures (I or II) to give the desired
Packard instrument with a chemical-ionization detector. High- N-alkylation product (Scheme 3).
performance liquid chromatography (HPLC) chromatograms
Preparation of reactional intermediate: 3,5-di-tert-butyl-
were obtained with a UV detector (λ = 254 nm) by using a 4-hydroxy benzyl chloride (1). Concentrated HCl (36%)
Kromasil (Phase Separations; Pessac, France) silica column (10 mL) was added to a solution of 3,5-di-tert-butyl-4-hy-
(
(
7
hexane–dichloromethane: 1:1) for 3–8, or a C18 Nucleosil droxy benzylic alcohol (10 g, 0.0423 mol) in CH Cl (100
2 2
Phase Separations) column (acetonitrile) for 1 and 2. A mL). The solution was stirred at room temperature for 6 h.
0–230-mesh silica gel was used for column chromatography. Several extractions were carried out with 100 mL water until
Satisfactory microanalyses were obtained for all compounds pH was neutral. The organic phase was dried with MgSO be-
4
(
Carlo Erba elemental analyzer; Rueil Malmaison, France).
Viscosities were measured with a Carri-Med CSL 100 C H OCl (M = 254.85 g/mol). Infrared (IR) (neat, cm ):
fore removing solvent to obtain 10.5 g of an orange oil (97%):
−
1
1
5 23
(
Rheo, Champlan, France) controlled-stress rheometer with a 3637 (νOH phenol), 1250–1166 (νC-O phenol), 3070 (νCH aro-
cone-plate geometry. Most of the properties were tested ac- matic ring), 1481, 1470 (νC=C tetrasubstituted aromatic), 885
cording to standard methods (10): (CH out of plane bending for tetrasubstituted aromatic), 785
NF M07-035 = ASTM D613-84 = ISO 5165. (Ref. 10) De- (C-Cl), 2873 (νCH CH ), 1435 (δ CH ). H NMR δ (ppm):
1
2
CH
2
termination of autoignition characteristics: compared to 1.45 (s, 18 H, CH of tBu); 4.6 (s, 2 H, CH -Cl); 5.3 (s, 1 H,
3
2
1
3
n-cetane and heptamethylnonane.
OH); 7.2 (s, 2 H, CH aromatic). C NMR δ (ppm) (Scheme
SCHEME 3
JAOCS, Vol. 74, no. 3 (1997)

DERIVATIVES OF ALKYLAMINO ALKYLOXY PROPANOL
243
ACYLATION REACTIONS ON ALCOHOL
AND AMINE GROUPS
The most appropriate reagent to prepare ester derivatives was
found to be an acid chloride. Acid anhydrides of fatty acids
are not available, and carboxylic acids are not efficient
enough to react with these derivatives without employing ex-
pensive catalysts.
SCHEME 4
4
): 30.3 (CH of tBu); 34.4 [C(CH ) ]; 47.7 (CH -Cl); 125.6
Esterification of hydroxy functions of similar compounds
3
3 3
2
(
C ); 128.3 (C ); 136.3 (C ); 154.1 (C ), attributed by com- with acetyl chloride has been described (12–14). We have
3 4 2 1
parison with calculated values (11).
shown that both amino and alcohol sites can be modified with
Synthesis of N-(3,5-di-tert-butyl-4-hydroxy) benzyl,N-(2- a fatty acid chloride in an appropriate solvent. Under such
hydroxy-3-octyloxy propyl) octylamine (2). A solution of 1- conditions, amide and ester functions were produced in the
octylamino-3-octyloxy-2-propanol (10 g, 0.032 mol) and tri- same reaction. Triethylamine favored the reaction the hy-
ethylamine (5 mL, 0.036 mol) in dichloromethane (50 mL) drochloric acid produced is trapped (Scheme 5).
was stirred at 40°C. A solution of 3,5-di-tert-butyl-4-hydroxy
As suggested above, the different –OH and –NH– groups
benzyl chloride (8.2 g, 0.032 mol) in diethyl ether (60 mL) of structures I, II, or III were readily acylated. For example,
was gradually added for 2 h. The medium was then stirred for the dimer structure 4 harbors four acylated sites (Scheme 6).
4
h. Several extractions were carried out with water (2 × 70
A tertiary amino function in the initial structure conferred
mL), then with HCl (pH = 5), and finally with water. The or- the same role as triethylamine, while for the derivatives with
ganic phase was dried (MgSO ) before removing solvent to an amide function, NMR revealed two configurational iso-
4
obtain 15.5 g of an orange oil. The product was further puri- mers that correspond to the forms shown in Scheme 7. Split
1
3
fied on a Florisil magnesium silicate (SDS) chromatography signals in proton and C NMR were observed.
column eluted with Et O. The product was characterized as
Synthesis of N-octyl, N-(3-octyloxy-2-octanoyloxy) propyl
follows: C H O N (M = 533.87 g/mol); n = 1.49080; octanamide (3b). A solution of octanoyl chloride (185 mL,
2
20
D
3
4
63
3
*
−1
UV-vis: λmax = 242 and 270 nm (π → π ). IR (neat, cm ): 1.07 mol:light excess) in diethyl ether (100 mL) was gradu-
430 (νOH alcohol), 3645 (νOH phenol), 1250 and 1155 (νC-O ally added to a solution of 1-octylamino-3-octyloxy-2-
3
phenol), 3070 (νCH aromatic ring), 1481 and 1470 (νC=C propanol (158 g, 0.5 mol) and triethylamine (140 mL, 1.0
tetrasubstituted aromatic), 1135 and 1119 (CH in-plane bend- mol) in diethyl ether (200 mL). The medium was then stirred
ing for tetrasubstituted aromatic), 885 (CH out-of-plane bend- for 5 h under reflux (35°C). The solution was first washed
ing for tetrasubstituted aromatic), 2925 to 2855 (ν CH2, with water, then several times with sat. aq. NaHCO , and fi-
CH
3
1
CH ), 1455 (δ CH , CH ). H NMR δ (ppm): 0.90 (m, 6 H, nally with water. Removal of solvent led to a yellow oil
CH ); 1.2 (m, 20 H, CH ); 1.35 (s, 18 H, CH of tBu); 1.45 (250 g, 90%): C H O N (M = 567.93 g/mol), n
3
CH
2
3
2
D
0
=
3
2
3
35 69
4
−
1
(
m, 4 H, CH β from O and N); 2.5 (m, 4 H, CH -N); 3.4 (5 H; 1.45667. UV-vis: λmax = 224 nm (n → π*). IR (neat, cm ):
2
2
d, CHAr, J = 13.3 Hz; t, O-CH , J = 6.9 Hz; 2 AB, CH -O, 1739 (νC=O ester), 1108 (νC-O ester), 1620 and 1653 (νC=O
2
2
JAB = 9.9 Hz); 3.65 (d, 1 H, CHAr, J = 13.3 Hz); 3.8 (m, X amide, 2 conformers), 1166 (νC-N), 1078 (νa C-O-C ether),
1
part of ABX, 1 H, CH); 5.1 (s, 1 H, Ar-OH); 7 (s, 2 H, CH 2955 to 2855 (νCH CH , CH ), 1467 (δ CH , CH ). H
2
3
CH
2
3
1
1
aromatic). Two-dimensional NMR (Cosy H- H) confirmed NMR δ (ppm): 0.85 (m, 12 H, CH ); 1.25 (m, 36 H, CH ); 1.6
3
2
that the doublet at 3.65 ppm belongs to the AM system, (m, 8 H, CH β from O, N and C=O); 2.3 [m, 4 H, CH C(O)N,
2
2
corresponding to the methylene diastereotopic protons CH C(O)O]; 3.3 [m, 4 H, C(O)-N-CH , CH -O]; 3.6 (AB,
2
2
2
1
3
Ar-CH -N. C NMR δ (ppm): 14.1 (CH ); 30.4 (CH tBu); 2 H, CH–CH –N–C=O, J = 13.5 Hz); 5.0, 5.15 (m, 0.5 H +
2
3
3
2
AB
1
3
2
7
1
2.6 to 34.3 (CH ); 54.0, 56.7, 58.6 (CH -N); 66.6 (CH); 0.5 H, CH, 2 isomers). C NMR δ (ppm): splitting of peaks
2 2
1.6, 73.4 (CH -O); 125.5 (H-C aromatic); 129.5 (C tBu); due to two configurational isomers; 14.0, 14.1 (CH ); 22.6 to
2
3
35.7 (H C-C aromatic); 152.8 (HO-C aromatic).
31.7 (CH ); 34.3 (CH –C=O); 46.3, 46.4, 47.5, 48.7 (2
2
2
2
SCHEME 5
JAOCS, Vol. 74, no. 3 (1997)

244
P. SATGÉ DE CARO ET AL.
NITRATION OF ALCOHOL AND AMINO FUNCTIONS
In novel nitration methods, generally, nitrated tetrafluorobo-
rate salts (15,16) or transfer nitration agents (17,18) are used.
Satisfactory results were not obtained with such methods, and
we therefore employed a conventional nitration method with
acid mixture. The nitration products were obtained in the ab-
sence of water or solvent in the medium. These experimental
conditions afforded products of high purity without using an
elaborated nitration agent. The same procedure was applied
to the different alkanolamine ethers and led to the nitrate 5,
the nitramines 6 and 7 or the dinitrate product 8 (Scheme 8).
A Lewis acid, such as zinc chloride, improved the quality
SCHEME 6
CH –N); 71.2, 71.5 (CH–OCO); 69.1, 70.3, 71.5, 71.6 (2 of the final compound by a better control of the exothermicity
2
CH –O); 172.9, 173.2 (O=C–N); 173.9, 174.1 (O=C–O). The of the reaction. These reagents enhanced nitration of hydroxyl
2
same procedure was employed to prepare the other acylated sites according to the mechanism decribed by Chute and
derivatives, but different amounts of octanoyl chloride and coworkers (19,20). Amino sites were nitrated in the absence
triethylamine were used. The yields were comparable.
of metal salts to prevent quaternization of the amine function.
Synthesis of 1-dibutylamino-3-(6-octanoyloxy hexyloxy)- Proportions of products 6 and 7 depended on the amount of
-octanoyloxy propane (3c). Octanoyl chloride (185 mL, 1.07 reagent, although they could be separated by crystallization
2
mol), 152 g (0.5 mol) of 1-dibutylamino-3-(6-hydroxy hexyl- of the dinitrate 7 from pentane.
oxy)-2-propanol (I), 140 mL (1 mol) of triethylamine:
Synthesis of 1-dibutylamino-2-nitrato-3-octyloxy propane
C H O N (M = 555.87 g/mol), n = 1.45566. UV-vis: (5). Fuming nitric acid (5 mL) was added dropwise for 10 min
2
0
3
3
65
5
D
−
1
λmax = 226 nm (n → π*). IR (neat, cm ): 1737 (ν
ester), to the stirred mixture of 1-dibutylamino-3-octyloxy-2-
C=O
1
108, 1050 (νa C-O-C ether, νC-O ester), 2930 to 2858 (ν
propanol (10 g, 0.032 mol) and ZnCl (2.2 g, 0.016 mol), fol-
CH
2
1
CH , CH ), 1465 (δ CH , CH ). H NMR δ (ppm): 0.8 (m, lowed by dropwise addition of acetic anhydride (5 mL). The
2
3
CH
2
3
1
2 H, CH ); 1.2 (m, 24 H, CH ); 1.5 (m, 12 H, CH β from O, medium was stirred for 45 min at 18°C under nitrogen and
3 2 2
N and C=O); 2.2 (m, 4 H, CH –C=O); 2.4 (td, 4 H, CH –N); then diluted in diethyl ether (50 mL). The mixture was neu-
2
2
2
.6 (2 AB, 2 H, CH–CH –N, J = 13.6 Hz); 3.4 (m, 4 H, tralized by several extractions with water and then with sat.
2 AB
CH –O); 4 [t, 2 H, CH –O–C(O), J = 6.6 Hz]; 5.1 (m, 1 H, aq. NaHCO until neutral pH of the aq. phase. The organic
2
2
3
1
3
CH). C NMR δ (ppm): 14.1 (CH ); 20.5 to 31.7 (CH ); phase was dried with MgSO before removing solvent. The
4.5, 35.3 [CH C(O)O]; 54.2 (CH –N); 54.5 [N(CH ) ]; 64.2 crude product was purified on a silica chromatography col-
3
2
4
3
2 2 2 2
[
CH –O–C(O)]; 70.6, 71.2 (CH –O); 71.0 (CH); 173.3, umn (eluted with Et O) to obtain 10.5 g of an orange oil
2
2
2
1
73.5, 173.9 (C=O).
(90%). The product was kept in solution (Et O) in the absence
2
2
0
Synthesis of di-[3-(N-octyl octamido)-2-octanoyloxy of light: C H O N (M = 360.52 g/mol), n = 1.46470;
1
9
40
4
2
D
−
1
propyloxy] hexamethylene (4a).Octanoyl chloride (370 mL, UV-vis: λmax = 226 nm (n → π*). IR (neat, cm ): 1635
2
propyloxy] hexamethylene (II), 280 mL (2 mol) of triethyl- cohol), 2950 to 2810 (ν CH , CH ), 1465 (δ CH , CH ).
amine: C H O N (M = 992.16 g/mol), n = 1.45967.
.15 mol), 245 g (0.5 mol) of di[(2-hydroxy-3-octylamino) (νa NO ), 1275 (νs NO2), 1123 (νa C-O-C ether), 1030 (νC-O al-
2
CH
2
3
CH
2
3
2
0
1
H NMR δ (ppm): 0.85 (m, 9 H, CH ); 1.25 (m, 14 H, CH );
2.4 (t, 4 H, N–CH , J = 6.2 Hz); 2.6 (d, 2 H, CH –N, J = 6.0
2 2
6
0
116
8
2
D
3 2
−
1
UV-vis: λmax = 222 nm (n → π*). IR (neat, cm ): 1738 (ν
C=O
ester), 1110 (νC-O ester), 1650 (νC=O amide), 1080 (νa C-O-C Hz); 3.3 (AA′ part of AA′XX′ system, 2 H, O–CH ); 3.6 (2
2
ether), 2955 to 2855 (ν CH , CH ), 1421 and 1465 (δ
dd(AMX), 2 H, CH–CH –O, J
= 0.66 Hz, J = 3.8 Hz,
CH
2
3
CH
2
AM AX
1
13
CH , CH ). H NMR δ (ppm): 0.85 (m, 18 H, CH ); 1.25 (m, JMX = 5.9 Hz); 5.2 (m, 1 H, CH). C NMR δ (ppm): 14.1
2
3
3
5
8
6 H, CH ); 1.5 (m, 16 H, CH β from O, N and C=O); 2.3 [t, (CH ); 20.5 to 31.6 (CH ); 53.3 (CH –N); 54.6 [N(CH ) ];
2 2
3 2 2 2 2
H, CH –C(O)O, CH –C(O)N]; 3.3 [m, 16 H, CH –N–C(O), 69.1, 71.6 (CH –O); 81.4 (CH–NO ). MS (m/z): 361 (M + 1);
2
2
2
2
2
1
3
+
+
CH –O]; 5.1 (m, 2 H, CH). C NMR δ (ppm): 14.1 (CH3); 316 [361 − 46 (NO )]; 190 [316 − 126 (C H N )]; 176
2
2
8
16
+
+
2
4
1
2.6 to 33.0 (CH ); 34.3, 34.5 [CH C(O)O, CH C(O)N]; [190 − 14 (CH )]; 130 [176 − 46 (C H OH )].
2 2 2
2 2 5
6.1, 48.8 (CH –N); 70.4, 71.7 (CH –O); 71.1 (CH); 173.2,
N-(2-hydroxy-3-octyloxy propyl), N-octyl nitramine (6)
and N-(2-nitrato-3-octyloxy propyl), N-octyl nitramine (7).
Fuming nitric acid (25 mL) was added dropwise for 15 min
to 1-octylamino-3-octyloxy-2-propanol (80 g, 0.25 mol)
under stirring, followed by dropwise addition of acetic anhy-
dride (23 mL). The medium was stirred for 3 h at 18°C under
nitrogen and was then diluted in diethyl ether (100 mL). The
mixture was neutralized by several extractions with water and
2
2
73.9 (C=O ester, amide).
SCHEME 7
then with sat. aq. NaHCO . The organic phase was dried
3
JAOCS, Vol. 74, no. 3 (1997)

DERIVATIVES OF ALKYLAMINO ALKYLOXY PROPANOL
245
SCHEME 8
2
0
(
MgSO ) before removing solvent. Compound 8 was crystal-
4
C H O N (M = 591.81 g/mol), n = 1.46068. UV-vis:
30 61 8 3 D
−1
lized from pentane to give a white solid (40 g), while 60 g of
were obtained as an orange oil. The product was kept in so-
lution (Et O) in the absence of light: (6) C H O N (M =
λmax = 250 nm (n → π*). IR (neat, cm ): 1633 (ν
), 1275
a NO
2
7
(
νs NO2), 1128 (νa C-O-C ether), 1044 (νC-O alcohol), 2925 to
1
2
19 39
6
3
2855 (νCH CH , CH ), 1465 (δ CH , CH ). H NMR δ
2 3 CH 2 3
−
1
4
(
(
0
05.52 g/mol). IR (neat, cm ): 1050 (ν
alcohol), 1663
C-O
(ppm): 0.85 (t, 9 H, CH ); 1.25 (m, 32 H, CH ); 1.5 (m, 4 H,
3 2
νa NO ), 1291 (νs N-NO2), 1120 (νa C-O-C ether), 2955 to 2855
CH β from O); 2.7 (XX′ part of AA′XX′ system, 2 H,
N–CH ); 3.4 (m, 4 H, CH–CH –N); 3.5 (m, 8 H, CH –O); 5.1
(m, 2 H, CH). C NMR δ (ppm): 14.1 (CH ); 22.7 to 31.6
(CH ); 53.8, 54.0, 55.5 (CH –N); 69.1, 71.9 (CH –O); 80.9,
2
2
1
νCH CH , CH ), 1398 (δ CH , CH ). H NMR δ (ppm):
2 3 CH 2 3
2
2
2
1
3
.85 (t, 6 H, CH ); 1.25 (m, 20 H, CH ); 1.5 (m, 2 H, CH β
3 2 2
3
from N); 1.65 (m, 2 H, CH β from O); 3.4 (m, 6 H, CH –O,
CH –N); 3.6 (d, 2 H, CH –O); 5.5 (m, 1 H, CH). C NMR δ
(
7
g/mol), n = 1.46570. UV-vis : λmax = 260 nm (n → π*). IR
(
(
(
2
2
2
2
2
1
3
1
5
2
2
81.0 (CH–NO2). N NMR δ (ppm): 380.2 (O–NO ); 195.9
2
ppm): 14.1 (CH ); 22.6 to 31.8 (CH ); 49.2, 46.6 (CH –N);
3 2 2
(R N–C H ). MS (m/z): 592 (M + 1); 379 [316 + 63
2
8
17
+
+
8.1 (CH); 72.2, 66.8 (CH –O). (7) C H O N (M = 360.52
2 19 40 4 2
(HNO )]; 361 [379 − 18 (H O )]; 190 [316 − 126
3 2
2
D
0
+
(C H N )].
8 16
−
1
neat, cm ): 3166 (νOH), 1050 (νC-O alcohol), 1635
νa NO ), 1275 (νs NO2), 1120 (νa C-O-C ether), 2955 to 2855
2
RESULTS AND DISCUSSION
1
νCH CH , CH ), 1463 (δ CH , CH ). H NMR δ (ppm):
2
3
CH
2
3
0
.85 (t, 6 H, CH ); 1.25 (m, 20 H, CH ); 1.5 (m, 2 H, CH β Physicochemical properties. The compounds were tested in
3 2 2
from N); 1.65 (m, 2 H, CH β from O); 3.4 (XX′ part of diesel fuel containing 15 vol% ethanol, at a proportion of
2
AA′XX′ + doublet, 4 H, CH –O); 3.6 to 3.9 (m, 4 H, CH –N); 2 wt% in the blend. Additive I was sometimes combined with
2
2
1
3
4
.1 (m, 1 H, CH). C NMR δ (ppm): 14.1 (CH ); 22.6 to 31.8 another additive, in the same formulation, at proportions of
3
(
CH ); 53.2, 54.4 (CH –N); 66.2 (CH); 71.8, 72.2 (CH –O). 2 × 1%. The synthesized compounds improved the character-
2 2 2
1
5
N NMR δ (ppm): 354.5 (NO ); 183.3 (N–NO ); MS (m/z): istics of ethanol-diesel fuel blends. Firstly, the emulsifying
2
2
+
+
3
2
79 [M + 18 (NH )]; 361 (M + 1); 316 [361 − 46 (NO )]; power of the compounds improved the stability of the blend.
4
2
+
+
98 [361 − 63 (HNO )]; 190 [316 − 126 (C H N )].
The results listed in Table 1 show that the additives retarded
N,N-di-(2-nitrato-3-octyloxy propyl) octylamine (8). Fum- the onset of turbidity due to phase separation. The perfor-
3
8 16
ing nitric acid (8 mL) was added dropwise for 10 min to a mance of the tested molecules was compared to that of a con-
stirred mixture of N,N-di-(2-hydroxy-3-octyloxy propyl) ventional cetane improver (Octel CI-0801; Octel Company,
octylamine (15 g, 0.03 mol) and ZnCl (2 g, 0.015 mol), fol- London, England).
2
lowed by dropwise addition of acetic anhydride (7 mL). The
The nitrate derivatives 5–8 were good cetane improvers
medium was stirred for 1 h at 18°C under nitrogen and was (Table 2). The resulting blends thus possess satisfactory self-
then diluted in diethyl ether (50 mL). The mixture was neu- ignition characteristics. The dinitrated derivatives 7 and 8 ap-
tralized by several extractions with water, then with sat. aq. peared to be the most efficient.
NaHCO . The organic phase was dried (MgSO ) before re-
Despite the hindered phenolic group in compound 2, de-
3
4
moving solvent to give 16 g of an orange oil (90%). The prod- rivatives 2 and I had similar antioxidative activity. A mixture
uct was kept in solution (Et O) in the absence of light. of compounds I and 6 also afforded resistance to oxidation,
2
JAOCS, Vol. 74, no. 3 (1997)

246
P. SATGÉ DE CARO ET AL.
TABLE 1
TABLE 3
Stability of 15% Ethanol Blends with 2% Additive, Tested
Under Influence of a Progressive Increase in Hydration
Antioxidative Activity (NF M07-047) for the Blends,
Standard Hydrocarbon Base + 2% Additive
Insoluble substances generated
1
0-mL samples
Duration of phase
stability
Compounds with n = 7, m = 7, r = 6
Addition components
R = H or ≠ H
under accelerated oxidation
conditions (mg/mL)
Blend without additive
1 h
1 h 30
a
Octel CI
Without additive
8
I
2
1–1.5
1
2
4 h
4 h
2 h
4 h 30
3 h
4 h
3b
3c
4a
5
6
6 + I
2–2.5
TABLE 4
I + 6
6 h
Low-Temperature Flow (LTF) Determination for 15% Ethanol Blends
with 2% Additive
aOctel CI is the commercial name for 2-ethyl hexyl nitrate.
Addition components
n = 7, m = 7, r = 6)
LTF (°C)
(NF M07-042)
(
although the nitrated compounds tend to be susceptible to ox-
-
idation (Table 3). Moreover, the ability to lower the cold flow Without additive
−12
−16
−18
−14
−18
−19
−18
2
3
3
4
6
temperature in the blend was improved for molecules that
possessed good emulsifying power, such as 3b, 4a, or 6 (Ta-
bles 1 and 4).
b
c
a
The derivatives also behaved as potential lubricants by im-
proving the viscosity of the blend. The additives stabilized 6 + I
the viscosity around 2 mPa · s when the temperature reached
5
0°C (Fig. 1). Two types of behavior were observed. Com-
pounds such as the ester derivatives induced a 40% gain in
viscosity at 50°C (curve b), while the other compounds (6 or
8
) led to a greater gain in viscosity, between 65 and 80%
(curves c and d). The thermal decomposition line shape of the
latter compounds indicated a polycondensation, which could
favor formation of a lubricating film.
In fact, we noted that the combination of structure I with a
nitrate derivative generated good polyfunctional activity (Ta-
bles 1–4).
Engines tests. Compared with conventional diesel fuel, the
blended fuel presented the same engine efficiency (8,9). With
1
0% ethanol and 2% additives, the ignition delay of a diesel
fuel was preserved. With 20% ethanol and 2% additives, the
oxides of nitrogen emissions were reduced between 5 and FIG. 1. Effect of additives on the viscosity curve as a function of tem-
perature. a) Diesel fuel + 15% ethanol = B; b) B + 2% addtive (2 to 5);
1
0%, depending on the load point. The smoke also decreased
c) B + 2% additive (III or 8); d) B + 2% additive 6.
between 30 and 60%. At cold start, the engine presented bet-
ter behavior when the blend was augmented with 2% addi-
tives.
Finally, the production cost for these synthetic procedures
was modest (8). The multifunctional activity of the com-
pounds makes them particularly attractive, especially because
only low proportions are required. A ternary fuel blend, such
as diesel fuel–ethanol additive, may thus have potential as an
alternative to diesel fuel (21).
TABLE 2
Cetane Number Determination (CFR engine) for 15% Ethanol Diesel
Fuel Blends with 2% Additive
Addition components
n = 7)
Cetane number
(NF M07-035)
(
ACKNOWLEDGMENTS
Without additive
5
6
7
8
I + 7
41.0
46.5
44.5
49.5
47.5
47.0
This work was supported by research grants from ADEME (Agence
de l’Environnement et de la Maîtrise de l’Energie) and the Direction
de la Recherche RENAULT. We thank E. Poitrat from ADEME and
J.C. Griesemann from RENAULT. Financial support was also pro-
vided by the Conseil Régional de Midi-Pyrénées.
JAOCS, Vol. 74, no. 3 (1997)

DERIVATIVES OF ALKYLAMINO ALKYLOXY PROPANOL
247
REFERENCES
10. Recueil des Normes Françaises AFNOR Produits pétroliers (Oil
products) - Combustibles liquides (Liquid fuels), Association
Française pour la Normalisation, Paris, Tome 1, 1988, pp.
1
. Macchia, B., A. Balsamo, A. Lapucci, F. Macchia, A. Martinelli,
H.L. Ammon, S.M. Prasad, M.C. Breschi, M. Ducci, and E.
Martinotti, Role of the (Acyloxy) Methyl Moiety in Eliciting the
Adrenergic β-blocking Activity of 3-(Acyloxy) propanolamines,
J. Med. Chem. 30(4):616–622 (1987).
3
51–361, pp. 427–443.
1
1
1
1. Pretsch, Clerc, Seibl, Simmons, Tables of Spectral Data for
Structure Determination of Organic Compounds, Springer-Ver-
lag, New York, 1985.
2. Greenhill, J.V., A Series of Amino-Alcohols Related to Benz-
hexol (1-Cyclohexyl-1-Phenyl-3-Piperidinopropan-1-ol), J.
Chem. Soc. C9:1298 (1970).
3. Mamedov, S., and F.A. Sharifora, Ethers of Glycols and Their
Derivatives: Synthesis of Alkoxymethyl Ethers from 1,3-Di-
alkoxy-2-Propanol, Otd. Obshch. Tekh. Khim.:29–33 (1967).
2
. Mauléon, D., M. Dolors-Pujol, and G. Rosell, β-Andrenergic
Antagonists: N-alkyl and N-amidoethyl (arylalkoxy)propanol-
amines Related to Propanolol, Eur. J. Med. Chem. 23:421–426
(
1988).
3
. Manoury, P.M., J.L. Binet, J. Rousseau, F.M. Lefevre-Borg, and
I.G. Cavero, Synthesis of a Series of Compounds Related to Be-
taxolol, A New β -Adrenoceptor Antagonist with a Pharmaco-
logical and Pharmacokinetic Profile Optimized for the Treat-
1
14. Trostmann, U., C. Schächtele, and K. Mannhardt, DE Patent No.
625738 A1 (1988).
3
ment of Chronic Cardiovascular Diseases, J. Med. Chem.
1
5. Olah, G.A., and C. Narang, Synthetic Methods and Reactions;
Convenient and Safe Preparation of Alkyl Nitrates (Polynitrates)
via Transfer Nitration of Alcohols (Polyols) with N-Nitrocolli-
dinium Tetrafluoroborate, Synthesis: 452–453 (1978).
3
0:1003–1011 (1987).
4
. Guivisdalsky, P.N., and R. Bittman, Glycidyl Derivatives, J.
Org. Chem. 54:4637–4642 (1989).
5
. Satgé de Caro, P., Z. Mouloungui, and A. Gaset, Synthesis of
Alkyloxy (di)Alkylamino Propanols, Hydroxy Alkylamino
Propanols and the Dimer Compounds for Use as Fuel Additives,
J. Am. Oil Chem. Soc. 74:235–240 (1997).
1
6. Cupas, C.A., and R.L. Pearson, Transfer Nitration via N-Ni-
tropyridinium Salts, J. Am. Chem. Soc. 90:4742 (1968).
1
7. Emmons, W.D., and J.P. Freeman, Alkaline Nitration: The Ni-
tration of Amines with Cyanohydrin Nitrates, Ibid.
6
. Davilov, A.M., Improvement of the Ecological Characteristics
of Fuels by Using Additives, Chem. Technol. Fuels Oils, trans-
lated from Khimiya Tekhnologiya Topliv i Masel 6:31–33
7
7:4387–4390 (1955).
1
1
8. Bottaro, J.C., R.J. Schmitt, and C.D. Bedford, Nonacidic Nitra-
tion of Secondary Amines, J. Org. Chem. 52:2292–2294 (1987).
9. Chute, W.J., G.E. Dunn, and J.C. MacKenzie, Catalyzed Nitra-
tion of Amine; III Ease of Nitration Among Aliphatic Secondary
Amines, Can. J. Res. 26B:114–137 (1948).
(
1990).
7
8
9
. Gasoline and Diesel Fuel Additives, Critical Reports on Applied
Chemistry, Vol. 25, edited by K. Owen, John Wiley & Sons,
New York, 1990.
. Satgé de Caro, P., Synthesis of Polyfunctional Oxygenated Ad-
ditives for Ethanol–Diesel Fuel Blends, Thèse INP Toulouse No.
2
0. Chute, W.J., K.G. Herring, L.E. Thoombs, and G.F. Wright,
Catalyzed Nitration of Amines: I Dinitroxydiethylnitramine,
Ibid. 26B:89–103 (1948).
1
001, Chap IV: Direct Injection Engine Tests, March 1995.
21. Mouloungui, Z., and P. Satgé de Caro, French Patents (Renault)
FR 95-02186 and FR 95-02187 (1995).
. Berge, J. Ch., and J. Andrzejewski, Comparative Tests of
Ethanol–Diesel Blends with Additives, Providing an Indirect In-
jection Engine, Laboratoire de Mécanique et d’Energétique de
l’ESEM (Université d’Orléans) in collaboration with the G.I.E.
de Recherche et d’Etudes PSA - Renault; Report of March 1996.
[Received April 30, 1996; accepted November 25, 1996]
JAOCS, Vol. 74, no. 3 (1997)