ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 6, pp. 1087!1089. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + N.V. Knyazeva, V.V. Kon
shin, N.A. Chemeris, M.M. Chemeris, 2008, published in Zhurnal Prikladnoi Khimii, 2008,
Vol. 81, No. 6, pp. 1047!1049.
Synthesis of Cellulose Esters with Aliphatic Hydroxy
Acids from Aspen Wood
N. V. Knyazeva, V. V. Kon
shin, N. A. Chemeris, and M. M. Chemeris
Polzunov Altai State Technical University, Barnaul, Russia
Received December 27, 2007
Abstract-Synthesis of cellulose esters with aliphatic hydroxy acids from aspen wood was studied
in relation to the reaction and isolation conditions.
Polymers prepared from aliphatic hydroxy acids
are promising materials combining various proper-
ties of plastics (thermoplasticity, capability to imi-
tate various polymers after appropriate plasticiza-
tion, etc.). At the same time, an important practical
property of such polymers is the capability to de-
grade under definite conditions to environmentally
harmless products: CO
O. The starting
materials for preparing such polymers are cellulose
esters with aliphatic hydroxy acids.
In a known procedure , cellulose esters with
aromatic carboxylic hydroxy acids are prepared by
treatment of cellulose with an acylating mixture
containing trifluoroacetic anhydride and aromatic
hydroxy acids as acylating agents . The reaction
is performed with addition of dichloromethane and
methanol. However, the process is multistep and
involves expensive solvents.
The previously developed [3, 4] procedure for
preparing cellulose esters expands the possibilities
of the synthesis of practically important cellulose-
based polymers containing bound carboxylic acids.
In the process, it is possible to use prehydrolyzed
aspen wood instead of pure cellulose.
The reaction of prehydrolyzed aspen wood (lig-
nocellulose material, LCM) containing 64.8% cel-
s method) and 35.2% lignin
s method ) with carboxylic hydroxy
acids of the general formula RCHOHCOOH (R =
) in trifluoroacetic acid (TFAA) was per-
formed in the presence of thionyl chloride (TC),
following the procedure described in :
RÄCÄCOOH + SOCl
RÄCÄCOOH + SOCl
After the reaction completion, the product was
precipitated into a polar solvent (water, acetone,
ethanol, isopropanol), washed, and dried to the air-
dry state. The lignin content was determined using
concentrated mineral acids , and the amount of
bound carboxylic hydroxy acids, by potentiometric
titration . Qualitative tests of the products for
halogens gave negative results.
One of the most important aspects of the syn-
thesis of cellulose esters from chemically modified
wood is the choice of a precipitant that would pro-
vide the optimal yield of the target product with
a fairly high content of bound carboxylic acid and
a low lignin content. The experiments showed that
isopropyl alcohol is a suitable precipitant for isolat-
ing the cellulose ester (Table 1). Isopropyl alcohol
ensures the maximal yield of cellulose hydroxyace-
tate with a high content of bound glycolic acid and
relatively small amount of lignin. With water, eth-
anol, or acetone as precipitant, the product yield is
considerably lower. The highest lignin content was
observed with water used as precipitant.