Catalytic conversion of ligno-cellulosic biomass into fuels and chemicals

Abstract

The invention provides a process for producing ethyl esters and hydrocarbons from lignocellulosic biomass materials. The process comprises two steps: the first step being an acid ethanolysis (solvolysis with ethanol) of the biomass in oxidizing medium; the second step being the catalytic conversion of the by-product diethyl ether and, optionally, light ethyl esters, into hydrocarbons over ZSM-5 zeolite catalyst. Cellulose, hemicellulose and part of the lignin are converted in the first step. The oxidizer used in this first conversion step is preferably and most preferably hydrogen peroxide activated by Fe (II) (Fenton-type reagent), and/or Ti (IV) ions. The final products may include ethyl levulinate (diesel-grade additive), light ethyl esters (ethyl formate and ethyl acetate), levulinic acid, succinic acid, methanol, gasoline-range hydrocarbons and C 2 -C 4 hydrocarbons.

1 . A method for converting ligno-cellulosic biomass materials into ethyl esters and hydrocarbons, said method comprising the following steps: (a) the chemical-catalytic conversion of the biomass material into ethyl levulinate, light ethyl esters and other products including diethyl ether carried out with alcohol as reactant and solvent in dilute acidic medium and in the presence of an oxidizing agent, (b) the chemical-catalytic conversion of at least one of the diethyl ether light ethyl esters into hydrocarbons by reaction with an acid nanocatalyst and (c) the recovery of the resulting products. 
     
     
         2 . The method of  claim 1  wherein the oxidizing agent is hydrogen peroxide. 
     
     
         3 . The method of  claim 1  wherein the oxidizing agent is a Fenton-type reagent. 
     
     
         4 . The method of  claim 1  wherein the oxidizing agent is hydrogen peroxide alone or hydrogen peroxide activated by at least one of Fe (II) ions or Ti (IV) ions. 
     
     
         5 . The method of  claim 1 , wherein the dilute acidic medium comprises an inhibitor of polymerization of aldehyde-type reaction intermediates. 
     
     
         6 . The method of  claim 1  wherein the acidic nano-catalyst is a zeolite of ZSM-5 type. 
     
     
         7 . The method of  claim 6  wherein the zeolite of ZSM-5 type has a Si/Al atom ratio ranging from 40 to 60. 
     
     
         8 . The method of  claim 7  wherein the ZSM-5 zeolite is modified Zn or Ga. 
     
     
         9 . The method of  claim 1 , wherein the resulting products comprise ethyl levulinate (diesel-grade additive), light ethyl esters, methanol, gasoline-range hydrocarbons, C 2 -C 4  hydrocarbons or mixtures thereof. 
     
     
         10 . The method of  claim 5 , wherein the inhibitor of polymerization of aldehyde-type reaction intermediates comprises sulfurous acid, para-toluene sulfonic acid, sodium sulfite, sodium carbonate, calcium carbonate, or any combination thereof. 
     
     
         11 . The method of  claim 9 , wherein the light ethyl esters are at least one of ethyl formate or ethyl acetate.