Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 4, pp. 613−617.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
L.Ya. Shteinberg, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 4, pp. 619−623.
ORGANIC SYNTHESIS AND INDUSTRIAL
Effect of Boric Acid Concentration on the Catalysis
of the Reaction of 4-Nitrobenzoic Acid with Ammonia
L. Ya. Shteinberg
Institute for Chemical Technology and Industrial Ecology, Research Institution,
Rubezhnoe, Lugansk oblast, Ukraine
Received August 13, 2007
Abstract—Effect of the catalyst concentration (boric acid + PEG-400) on the formation rate and yield of
4-nitrobenzamide in the reaction of 4-nitrobenzoic acid with ammonia was studied.
It has been found previously that the system boric acid +
PEG effectively catalyzes formation of 4-nitrobenzamide
(PNBAm) in the reaction of 4-nitrobenzoic acid (PNBA)
with ammonia [1–3]. The effect of the nature of solvents,
PEG and other cocatalysts, and the reaction temperature
on the yield of the target product has been studied. It has
been noted that the catalysis is efﬁ cient at various boric
acid : PNBA and PEG : PNBA ratios when the reaction
is performed in aprotic solvents. No PNBAm is formed
in the absence of PEG or in amidation of PNBA in protic
The aim of this study was to examine the inﬂ uence
exerted by the amount of boric acid and PEG on the yield
and formation rate of 4-nitrobenzamide.
PNBA was reacted with ammonia in aprotic solvents with
different polarities (trichlorobenzene, o-dichlorobenzene,
n-decane), in which, as it has been shown previously ,
PNBA can be obtained in high yield. PEG-400 was used as
a cocatalyst; in all the experiments, the boric acid : PEG-
400 molar ratio was 2 : 1:
Figure 1 shows kinetic curves of PNBAm accumulation
in the course of time in relation to the amount of boric
acid used. It was found that the kinetic curves have
two different shapes in various solvents, depending on
the solvent nature. When the reaction is performed in
o-dichlorobenzene and trichlorobenzene (Figs. 1a and
1b), the kinetic curves are linear up to large degrees
of conversion (70–75%). PNBAm is formed in nearly
quantitative yield in 8–9 h. When the amidation is
performed in decane (Fig. 1c), the kinetic curves are linear
up to conversions of 8–60%, depending on the amount
Fig. 1. PNBAm yield X vs. time τ at various amounts of boric
acid used. Solvent: (a) 1,2,4-trichlorobenzene, 173°C; (b)
o-dichlorobenzene, 163°C; and (c) n-decane, 174°C. H
(mol % relative to PNBA): (a, b) (1) 0, (2) 0.5, (3) 1, (4) 2, (5)
5, (6) 10, (7) 15, (8) 20, (9) 28, (10) 34, and (11) 43; (c) (1) 0,
(2) 2, (3) 5, (4) 10, (5) 15, (6) 20, (7) 28, (8) 34, and (9) 43.