Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 6, pp. 841−844.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © V.V. Kotova, V.Z. Maslosh, O.V. Maslosh, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 6, pp. 898−901.
AND INDUSTRIAL ORGANIC CHEMISTRY
Dicarboxylic Acids Amides as an Acceptor of Formaldehyde
in Urea-Formaldehyde Resins
V. V. Kotova, V. Z. Maslosh, and O. V. Maslosh
Institute of Chemical Technology of East Ukrainian National University, Rubezhnoe, Ukraine
Received May 16, 2013
Abstract—The possibility of reducing the content of free formaldehyde in urea-formaldehyde resin by introducing
into the ﬁ nal resin composition of diphthalic and dimaleic acids amides was studied. It was found that the amides
synthesized are able to participate in formaldehyde addition as well as in its polymerization and they are effective
acceptor of formaldehyde in urea-formaldehyde resins.
Usage of carboxylic acids and their anhydrides as
modifying additives to reduce the free formaldehyde
content in the urea-formaldehyde resins (UFR) is known
and reported in the literature .
The reaction of formaldehyde with carboxylic acids
formed mostly unstable compounds in the form of meth-
ylene glycol esters or polyoxymethylene glycols :
RCOOH + CH
O = RCOOCH
O + HNR
Reactions of formaldehyde with acid anhydrides
leads to the formation of methyl and dioxymethylene
O + CH
O = CH
O + 2 CH
These compounds are more stable than polyoxy-
methylene glycols, but at the melting point and below
Diphthalic (P) and dimaleic (M) acids amides
produced from the reaction of urea with maleic and
phthalic anhydrides in a molar ratio of 1 : 2 were used in
the present work as the additives that reduce the toxicity
of urea-formaldehyde resins.
Preparation of diphthalic and dimaleic acids amides
was carried out according to the terms of a patent .
A preliminarily homogenized mixture of 1 mol of
urea and 2 moles of phthalic (or maleic) anhydride was
charged in a hopper of a hammer micromill. The process
in the micromills was carried out until the desired acid
number. The resulting product was in the form of white
powder of 3–10 μm dispersion. Properties of amides are
shown in Table 1.
Compositions based on resin KF-MT-15 with
the addition of amides. Example 1. In a glass beaker
(250 ml) 100 g of resin (the content of free CH
0.12%) and 0.079 g of dimaleic (M) acid amide in term
of 0.049 moles of CH
O were charged. The resulting
mixture was thoroughly stirred for 30–40 minutes at
room temperature. Then the resin was analyzed for free
formaldehyde and was kept for observation for 45 days
with regular performing a full analysis of the resin
according to State Standard TU 6-05761672.186-2000.
In the case of using a resin containing 0.25% of free
formaldehyde per 100 g of resin 0.15 g of (M) acid
amide in term of 0.049 moles of CH
O per 1 g of the
amide was added (Table 1).
Example 2. The composition was prepared similar