This invention relates to a method for the conversion of lignocellulosic biomass into ethyl esters of carboxylic acids. Said method consists of treating the biomass material with an oxidizing agent that is incorporated in an solution comprising one or more acids, one or more alcohols and water, and subsequently performing a catalytic reaction at a higher temperature using the same acidic solution into which a larger volume of alcohol is added, in such a way that the catalytic conversion occurs in a medium with a much higher concentration of alcohol, i.e. with a much higher alcohol-to-water wt ratio. Such a method results in relatively high yields of ethyl esters, such as ethyl esters of formic, acetic, and levulinic acids, while producing a low yield of dialkyl ethers, which are unwanted by-products. The concentration of the oxidizing agent in the pre-treatment step is preferably higher than 6.0 wt %. The oxidizing agent is preferably a Fenton or Fenton-type reagent, and most preferably hydrogen peroxide activated by Fe (II), and/or Ti (IV) ions. The alcohol is preferably ethanol, and when ethanol is used, diethyl ether is formed as the unwanted dialkyl ether by-product. Preferably, the biomass material is pelleted before treatment.

This invention relates to a method for the conversion of lignocellulosic biomass into ethyl esters of carboxylic acids. Said method consists of treating the biomass material with an oxidizing agent that is incorporated in an solution comprising one or more acids, one or more alcohols and water, and subsequently performing a catalytic reaction at a higher temperature using the same acidic solution into which a larger volume of alcohol is added, in such a way that the catalytic conversion occurs in a medium with a much higher concentration of alcohol, i.e. with a much higher alcohol-to-water wt ratio. Such a method results in relatively high yields of ethyl esters, such as ethyl esters of formic, acetic, and levulinic acids, while producing a low yield of dialkyl ethers, which are unwanted by-products. The concentration of the oxidizing agent in the pre-treatment step is preferably higher than 6.0 wt %. The oxidizing agent is preferably a Fenton or Fenton-type reagent, and most preferably hydrogen peroxide activated by Fe (II), and/or Ti (IV) ions. The alcohol is preferably ethanol, and when ethanol is used, diethyl ether is formed as the unwanted dialkyl ether by-product. Preferably, the biomass material is pelleted before treatment.

A process for producing levulinic acid includes a step of catalytic conversion of a pentose (in particular xylose or arabinose) into furfural in an organic solvent having a boiling temperature from 60° C. to 220° C., followed by a step of reduction of furfural to furfuryl alcohol, in the presence of a Lewis acid as catalyst and a protic solvent. Eventually, furfuryl alcohol is converted into levulinic acid directly or indirectly, by preliminary conversion into a levulinic acid ester and its subsequent hydrolysis. This process has a reduced environmental impact and guarantees satisfactory process yields on an industrial scale. In particular, the process allows to reduce as much as possible the formation of humins, which require complex and costly purification processes and involve a considerable reduction in the levulinic acid yields.

A process for producing levulinic acid includes a step of catalytic conversion of a pentose (in particular xylose or arabinose) into furfural in an organic solvent having a boiling temperature from 60° C. to 220° C., followed by a step of reduction of furfural to furfuryl alcohol, in the presence of a Lewis acid as catalyst and a protic solvent. Eventually, furfuryl alcohol is converted into levulinic acid directly or indirectly, by preliminary conversion into a levulinic acid ester and its subsequent hydrolysis. This process has a reduced environmental impact and guarantees satisfactory process yields on an industrial scale. In particular, the process allows to reduce as much as possible the formation of humins, which require complex and costly purification processes and involve a considerable reduction in the levulinic acid yields.

The present disclosure relates to a process for producing levulinic acid from the technical lignin. The technical lignin is rich in lignin and ash and do not have any other use and usually incinerated as a waste management strategy. During the incineration process, the cellulose also gets burnt and wasted. In the present disclosure, there is provided an economical and environmentally friendly process to produce levulinic acid from the technical lignin by using a synergistic combination of catalysts for high yields and high titer with acid recycling in a cost-effective manner

The present disclosure relates to a process for producing levulinic acid from the technical lignin. The technical lignin is rich in lignin and ash and do not have any other use and usually incinerated as a waste management strategy. During the incineration process, the cellulose also gets burnt and wasted. In the present disclosure, there is provided an economical and environmentally friendly process to produce levulinic acid from the technical lignin by using a synergistic combination of catalysts for high yields and high titer with acid recycling in a cost-effective manner

A sulfonic acid or carboxylic acid containing a carbonyl group, or a salt thereof represented by the following formula:
R.sup.1—C(═O)—(CR.sup.2.sub.2).sub.n—(OR.sup.3).sub.p—(CR.sup.4.sub.2).sub.q-L-A
wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, n, p, q, A and L are as defined herein.

Provided are methods for producing levulinic acid from hemp hurds. In some embodiments, the methods include dissolving hemp hurds in an ionic liquid medium to produce a cellulose-rich product; hydrolyzing cellulose present in the cellulose-rich product to produce a glucose-rich product; dehydrating glucose present in the glucose-rich product, and/or fructose resulting from isomerization of the glucose, to produce 5-hydroxymethyl furfural (HMF); and hydrolyzing the HMF to levulinic acid. Also provided are methods for method for producing levulinic acid from sugar sources generally, which can include providing a sugar source, wherein the sugar source is a hydrolysis product produced by hydrolyzing a cellulose-rich product generated from hemp hurds and/or a cellulase digestion product of softwood pre-treated with phosphoric acid (H3PO4) or another acid; dehydrating the glucose present in the sugar source, and/or fructose resulting from isomerization of glucose present in the sugar source, to produce 5-hydroxymethyl furfural (HMF); and hydrolyzing the HMF to produce levulinic acid.

Provided are methods for producing levulinic acid from hemp hurds. In some embodiments, the methods include dissolving hemp hurds in an ionic liquid medium to produce a cellulose-rich product; hydrolyzing cellulose present in the cellulose-rich product to produce a glucose-rich product; dehydrating glucose present in the glucose-rich product, and/or fructose resulting from isomerization of the glucose, to produce 5-hydroxymethyl furfural (HMF); and hydrolyzing the HMF to levulinic acid. Also provided are methods for method for producing levulinic acid from sugar sources generally, which can include providing a sugar source, wherein the sugar source is a hydrolysis product produced by hydrolyzing a cellulose-rich product generated from hemp hurds and/or a cellulase digestion product of softwood pre-treated with phosphoric acid (H3PO4) or another acid; dehydrating the glucose present in the sugar source, and/or fructose resulting from isomerization of glucose present in the sugar source, to produce 5-hydroxymethyl furfural (HMF); and hydrolyzing the HMF to produce levulinic acid.

The present invention refers to a process for the purification of levulinic acid, an aqueous solution comprising levulinic acid and a process for the production of levulinic acid.