Andrew, JEGrzeskowiak, VKerr, I2011-01-202011-01-202009-10Andrew, J, Grzeskowiak, V and Kerr, I. 2009. Hexenuronic acid in South African Eucalyptus hybrid clones: optimization of the acid hydrolysis (A) stage. Tappi Journal, Vol. 8(10), pp 4-12http://www.tappi.org/Bookstore/Technical-Papers/Journal-Articles/TAPPI-JOURNAL/Archives/2009/October/Table-of-Contents/Hexenuronic-Acid-in-South-African-Eucalyptus-Hybrid-Clones-Optimization-of-the-Acid-Hydrolysis-A-.aspxhttp://hdl.handle.net/10204/4779Copyright: 2009 TappiHexenuronic acid (HexA) is formed during kraft pulping by the conversion of 4-O-methyl-glucuronic acid groups in strong alkali conditions. HexA can be removed from the pulp by including an acid hydrolysis (A) stage in the bleaching sequence. Despite a significant body of work in this area, very little research has been carried out to examine HexA in pulps produced from South African-grown tree species under the conditions of the local pulp and paper industry. The objective of this paper, which is part of a broader study, was to determine the optimum conditions in the A-stage that resulted in maximum removal of HexA, but with minimum impact on the physical and chemical properties of the pulp after bleaching. For this purpose, oxygen delignified pulps produced from a Eucalyptus hybrid clone, E. grandis x E. urophylla, were subjected to acid hydrolysis at varied temperature and reaction times. The pH was kept constant at 3.5 for all experiments. The results showed that the A-stage was efficient in the removal of HexA; acid hydrolysis carried out at 125 degrees Celcius-180min removed as much as 98% of the HexA, resulting in a kappa number reduction of approximately 6 units.enHexenuronic acidAcid HydrolysisPulpPaper industryEucalypt hybridsEucalyptus kraft pulpingBleaching technologiesArticleAndrew, J., Grzeskowiak, V., & Kerr, I. (2009). Hexenuronic acid in South African Eucalyptus hybrid clones: optimization of the acid hydrolysis (A) stage. http://hdl.handle.net/10204/4779Andrew, JE, V Grzeskowiak, and I Kerr "Hexenuronic acid in South African Eucalyptus hybrid clones: optimization of the acid hydrolysis (A) stage." (2009) http://hdl.handle.net/10204/4779Andrew J, Grzeskowiak V, Kerr I. Hexenuronic acid in South African Eucalyptus hybrid clones: optimization of the acid hydrolysis (A) stage. 2009; http://hdl.handle.net/10204/4779.TY - Article AU - Andrew, JE AU - Grzeskowiak, V AU - Kerr, I AB - Hexenuronic acid (HexA) is formed during kraft pulping by the conversion of 4-O-methyl-glucuronic acid groups in strong alkali conditions. HexA can be removed from the pulp by including an acid hydrolysis (A) stage in the bleaching sequence. Despite a significant body of work in this area, very little research has been carried out to examine HexA in pulps produced from South African-grown tree species under the conditions of the local pulp and paper industry. The objective of this paper, which is part of a broader study, was to determine the optimum conditions in the A-stage that resulted in maximum removal of HexA, but with minimum impact on the physical and chemical properties of the pulp after bleaching. For this purpose, oxygen delignified pulps produced from a Eucalyptus hybrid clone, E. grandis x E. urophylla, were subjected to acid hydrolysis at varied temperature and reaction times. The pH was kept constant at 3.5 for all experiments. The results showed that the A-stage was efficient in the removal of HexA; acid hydrolysis carried out at 125 degrees Celcius-180min removed as much as 98% of the HexA, resulting in a kappa number reduction of approximately 6 units. DA - 2009-10 DB - ResearchSpace DP - CSIR KW - Hexenuronic acid KW - Acid Hydrolysis KW - Pulp KW - Paper industry KW - Eucalypt hybrids KW - Eucalyptus kraft pulping KW - Bleaching technologies LK - https://researchspace.csir.co.za PY - 2009 T1 - Hexenuronic acid in South African Eucalyptus hybrid clones: optimization of the acid hydrolysis (A) stage TI - Hexenuronic acid in South African Eucalyptus hybrid clones: optimization of the acid hydrolysis (A) stage UR - http://hdl.handle.net/10204/4779 ER -