Abstract
The chemical composition of Acacia mearnsii wood extract is described in this paper for the first time. This wood is cultivated in Brazil and has been used to complement the demand for hardwood in the pulp industry. In this study, we performed extractions with acetone (total extracts) and dichloromethane (lipophilic extracts responsible for the pitch formation), with the obtained percentages being 1.68 and 0.68%, respectively. The lipophilic extracts were derivatized and analyzed by Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) before and after alkaline hydrolysis. The results showed that 57 compounds were detected in the lipophilic extracts and these are mainly constituted by fatty acids ca. 32.8 mg kg-1 and sterols 26.9 mg kg-1. These chemical classes have always been present in pitch deposits in the pulp industry. Therefore, these results may be used by pulp mills to establish strategies for pitch control and represent an important advance in the knowledge of A. mearnsii.
Highlights
IntroductionPopularly known as black wattle or mimosa, is a medium-sized tree in the Fabaceae (Leguminosae) family, native to southeastern Australia, being the only temperate Acacia specie grown commercially on a significant international scale, as it presents high productivity and fast adaptation to different environmental conditions.[1,2,3,4]The species was introduced in several countries around the world in the second half of the 19th century, mainly as a source of fuel, but it was the initial success and first exports of plantation tannins in South Africa that stimulated international interest in the species.[2]A. mearnsii wood usually has high density and low lignin content that provides a high yield and cellulosic pulp which is delignified and bleached.[5,6] These characteristics confer economic advantages for pulp production, as well as transportation and storage.[2]Currently, A. mearnsii cultivation mainly occurs in South Africa and southern Brazil, constituting the two the content of lipophilic extracts is in the range of 2 to 4% of the hardwood mass, the total removal of these compounds is not always successfully achieved under the conditions of obtaining cellulose pulp in most of them.[14,15] the smallest possible amount of these constituents remaining in the pulping step is highly desirable to minimize fouling problems formed by extracts in bleaching steps and further processing of the pulp.[10,16,17]
The objective of this work was to characterize the chemical composition of the lipophilic extracts from A. mearnsii wood cultivated in Brazil through gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FTIR) analysis
The total amount of extract soluble in acetone from A. mearnsii wood was 1.68 ± 0.01% (m/m). This value is much lower than the values found for E. camaldulensis (3.72%) and E. urophylla (2.93%), and it is slightly higher than E. urograndis (1.32%) and E. globulus (1.52%).[20,21]
Summary
Popularly known as black wattle or mimosa, is a medium-sized tree in the Fabaceae (Leguminosae) family, native to southeastern Australia, being the only temperate Acacia specie grown commercially on a significant international scale, as it presents high productivity and fast adaptation to different environmental conditions.[1,2,3,4]The species was introduced in several countries around the world in the second half of the 19th century, mainly as a source of fuel, but it was the initial success and first exports of plantation tannins in South Africa that stimulated international interest in the species.[2]A. mearnsii wood usually has high density and low lignin content that provides a high yield and cellulosic pulp which is delignified and bleached.[5,6] These characteristics confer economic advantages for pulp production, as well as transportation and storage.[2]Currently, A. mearnsii cultivation mainly occurs in South Africa and southern Brazil, constituting the two the content of lipophilic extracts is in the range of 2 to 4% of the hardwood mass, the total removal of these compounds is not always successfully achieved under the conditions of obtaining cellulose pulp in most of them.[14,15] the smallest possible amount of these constituents remaining in the pulping step is highly desirable to minimize fouling problems formed by extracts in bleaching steps and further processing of the pulp.[10,16,17]. A. mearnsii wood usually has high density and low lignin content that provides a high yield and cellulosic pulp which is delignified and bleached.[5,6] These characteristics confer economic advantages for pulp production, as well as transportation and storage.[2]. A. mearnsii cultivation mainly occurs in South Africa and southern Brazil, constituting the two the content of lipophilic extracts is in the range of 2 to 4% of the hardwood mass, the total removal of these compounds is not always successfully achieved under the conditions of obtaining cellulose pulp in most of them.[14,15] the smallest possible amount of these constituents remaining in the pulping step is highly desirable to minimize fouling problems formed by extracts in bleaching steps and further processing of the pulp.[10,16,17]
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