Oxidation of lignin and polysaccharides mediated by polyoxometalate treatment of wood pulp

A method for oxidative degradation of lignin and polysaccharide fragments dissolved during polyoxometalate treatment of wood fiber, comprising the steps of:

• obtaining wood fiber;
• mixing the wood fiber with a solution of a polyoxometalate of the formula [V.sub.l Mo.sub.m W.sub.n Nb.sub.o Ta.sub.p (TM).sub.q X.sub.r O.sub.s ].sup.x- where l is 0-18, m is 0-40, n is 0-40, o is 0-10, p is 0-10, q is 0-9, r is 0-6, TM is a d-electron-containing transition metal ion, and X is a heteroatom, which is a p or d block element, where l+m+n+o+p.gtoreq.4, l+m+q>0 and s is sufficiently large that x>0, wherein the fiber is of a consistency of 1-20%, wherein the fiber is delignified, the polyoxometalate is reduced, and the lignin and polysaccharide fragments within the pulp are dissolved, and wherein a liquor is obtained that contains the polyoxometalate and dissolved lignin and polysaccharide fragments, and
• heating the liquor in the presence of a gaseous oxidant, wherein oxidation takes place, under conditions wherein the polyoxometalate is oxidized and the dissolved lignin and polysaccharide fragments are catalytically and oxidatively degraded by the oxidant and the polyoxometalate to volatile organic compounds and water,
• wherein the pressure of the oxidant in the heating step is 15 to 1000 psia,
• wherein the temperature of the heating step is between 100.degree. C. and 400.degree. C.,
• wherein the heating step is performed at final pH of between 1.0 And 10.0,
• wherein the time of oxidation is between 0.5 hr and 10.0 hrs, and
• wherein the heating step takes place in a vessel capable of withstanding said pressure.

A method for oxidative degradation of lignin and polysaccharide fragments dissolved during polyoxometalate treatment of pulp obtained from a non-woody plant, comprising the steps of:

• obtaining a pulp from a non-woody plant;
• mixing the pulp with a solution of a polyoxometalate of the formula [V.sub.l Mo.sub.m W.sub.n Nb.sub.o Ta.sub.p (TM).sub.q X.sub.r O.sub.s ].sup.x- where l is 0-18, m is 0-40, n is 0-40, o is 0-10, p is 0-10, q is 0-9, r is 0-6, TM is a d-electron-containing transition metal ion, and X is a heteroatom, which is a p or d block element, where l+m+n+o+p.gtoreq.4, l+m+q>0 and s is sufficiently large that x>0, wherein the pulp is of a consistency of 1-20%, wherein the pulp is delignified, the polyoxometalate is reduced, and the lignin and polysaccharide fragments within the pulp are dissolved, and wherein a liquor is obtained that contains the polyoxometalate and dissolved lignin and polysaccharide fragments, and
• heating the liquor in the presence of a gaseous oxidant, wherein oxidation takes place, under conditions wherein the polyoxometalate is oxidized and the dissolved lignin and polysaccharide fragments are catalytically and oxidatively degraded by the oxidant and the polyoxometalate to volatile organic compounds and water,
• wherein the pressure of the oxidant in the heating step is 15 to 1000 psia,
• wherein the temperature of the heating step is between 100.degree. C. and 400.degree. C.,
• wherein the heating step is performed at final pH of between 1.0 And 10.0,
• wherein the time of oxidation is between 0.5 hr and 10.0 hrs, and
• wherein the heating step takes place in a vessel capable of withstanding said pressure.

A method for oxidative degradation of lignin and polysaccharide fragments dissolved during polyoxometalate treatment of wood pulp, comprising the steps of:

• obtaining a wood pulp;
• mixing the wood pulp with a solution of a polyoxometalate of the formula [V.sub.l Mo.sub.m W.sub.n (TM).sub.o P.sub.5 C.sub.p Na.sub.q O.sub.r ].sup.x-, where TM is any d-electron-containing transition metal ion, C is a di- or tri-valent p, d, or f block cation located in the center of the structure, l+m+n+o=30, p+q=1 and l+m+o>0 and r is sufficiently large that x>0, wherein the pulp is of a consistency of 1-20%, wherein the pulp is delignified, the polyoxometalate is reduced, and the lignin and polysaccharide fragments within the pulp are dissolved, and wherein a liquor is obtained that contains the polyoxometalate and dissolved lignin and polysaccharide fragments, and
• heating the liquor in the presence of a gaseous oxidant, wherein oxidation takes place, under conditions wherein the polyoxometalate is oxidized and the dissolved lignin and polysaccharide fragments are catalytically and oxidatively degraded by the oxidant and the polyoxometalate to volatile organic compounds and water,
• wherein the pressure of the oxidant in the heating step is 15 to 1000 psia,
• wherein the temperature of the heating step is between 100.degree. C. and 400.degree. C.,
• wherein the heating step is performed at final pH of between 1.0 And 10.0, and
• wherein the time of oxidation is between 0.5 hr and 10.0 hrs, and
• wherein the heating step takes place in a vessel capable of withstanding said pressure.