Classifications

• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/02—Preparation of oxygen-containing organic compounds containing a hydroxy group
  • C12P7/04—Preparation of oxygen-containing organic compounds containing a hydroxy group acyclic
  • C12P7/06—Ethanol, i.e. non-beverage
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/02—Preparation of oxygen-containing organic compounds containing a hydroxy group
  • C12P7/04—Preparation of oxygen-containing organic compounds containing a hydroxy group acyclic
  • C12P7/06—Ethanol, i.e. non-beverage
  • C12P7/08—Ethanol, i.e. non-beverage produced as by-product or from waste or cellulosic material substrate
  • C12P7/10—Ethanol, i.e. non-beverage produced as by-product or from waste or cellulosic material substrate substrate containing cellulosic material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D11/00—Solvent extraction
  • B01D11/04—Solvent extraction of solutions which are liquid
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
  • C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
  • C07D307/04—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members
  • C07D307/06—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, directly attached to ring carbon atoms
  • C07D307/08—Preparation of tetrahydrofuran
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
  • C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
  • C07D307/34—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
  • C07D307/36—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, directly attached to ring carbon atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
  • C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
  • C07D307/34—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
  • C07D307/38—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with substituted hydrocarbon radicals attached to ring carbon atoms
  • C07D307/40—Radicals substituted by oxygen atoms
  • C07D307/46—Doubly bound oxygen atoms, or two oxygen atoms singly bound to the same carbon atom
  • C07D307/48—Furfural
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
  • C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
  • C07D307/34—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
  • C07D307/38—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with substituted hydrocarbon radicals attached to ring carbon atoms
  • C07D307/40—Radicals substituted by oxygen atoms
  • C07D307/46—Doubly bound oxygen atoms, or two oxygen atoms singly bound to the same carbon atom
  • C07D307/48—Furfural
  • C07D307/50—Preparation from natural products
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P17/00—Preparation of heterocyclic carbon compounds with only O, N, S, Se or Te as ring hetero atoms
  • C12P17/02—Oxygen as only ring hetero atoms
  • C12P17/04—Oxygen as only ring hetero atoms containing a five-membered hetero ring, e.g. griseofulvin, vitamin C
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E50/00—Technologies for the production of fuel of non-fossil origin
  • Y02E50/10—Biofuels, e.g. bio-diesel

Definitions

• non-food, lignocellulosic biomasses might be contemplated of this character, including, for example, purpose-grown non-food biomass crops (such as grasses, sweet sorghum, fast growing trees), or more particularly wood wastes (such as prunings, wood chips, sawdust) and green wastes (for instance leaves, grass clippings, vegetable and fruit wastes).
• purpose-grown non-food biomass crops such as grasses, sweet sorghum, fast growing trees
• wood wastes such as prunings, wood chips, sawdust
• green wastes for instance leaves, grass clippings, vegetable and fruit wastes.
• Lignocellulosic biomasses are comprised mainly of cellulose, hemicellulose and lignin fractions, with cellulose being the largest of these three components.
• Cellulose derives from the structural tissue of plants, and consists of long chains of beta glucosidic residues linked through the 1 ,4 positions. These linkages cause the cellulose to have a high crystallinity and thus a low accessibility to the enzymes or acid catalysts which have been suggested for hydrolyzing the cellulose to C6 sugars (or hexoses) for further processing.
• Hemicellulose by contrast is an amorphous heteropolymer which is easily hydrolyzed, while lignin, an aromatic three- dimensional polymer, is interspersed among the cellulose and hemicellulose within a plant fiber cell and has presented the most significant challenges for further processing and upgrading.
• pelletized, weak acid-processed biomass is washed with a solvent or solvent mixture which is effective for separating the solubilized and depolymerized hemicelluloses and lignins from a cellulosic fraction of the biomass, and then the cellulosic fraction is contacted with a second, strong mineral acid (or acids) under conditions suited to providing a hexose product or stream.
• a solvent or solvent mixture which is effective for separating the solubilized and depolymerized hemicelluloses and lignins from a cellulosic fraction of the biomass, and then the cellulosic fraction is contacted with a second, strong mineral acid (or acids) under conditions suited to providing a hexose product or stream.
• the first, weak organic acid is applied to the biomass in a vapor form at elevated temperatures, in part to reduce the drying load prior to the peptization step.
• a method and improvements to the method are described for processing a lignocellulosic biomass to form an acylated cellulose pulp, that includes contacting a lignocellulosic biomass with a first amount of a C1-C2 acid selected from the group consisting of acetic acid, formic acid and mixtures of the same.
• the contacted lignocellulosic biomass is heated to a temperature and for a time sufficient to hydrolytically release a first portion of hemicellulose and lignin, forming a hydrolysate liquid and an acylated lignocellulosic cake.
• the acylated lignocellulosic cake is separated from the first hydrolysate liquid and is contacted with a second amount of the C1-C2 acid to wash hemicellulose and lignin from the acylated lignocellulosic cake.
• the acid wash liquid including soluble hemicellulose and lignin is separated from the acid washed cake and the cake is contacted with a first amount of a C1-C2 acid-miscible organic solvent to further wash the C1-C2 acid, hemicellulose and lignin from the acid washed acylated cake leaving an acylated cellulose pulp, which is separated from the C1-C2 acid-miscible solvent wash liquid.
• the solvent wash liquid can be combined with at least one of the hydrolysate and the acid wash liquid forming an acidic organic solvent extract.
• the acidic organic solvent extract is condensed, forming an acidic organic solvent syrup enriched with hemicellulose and lignin.
• a second amount of the C1-C2 acid-miscible organic solvent may be added, the second amount being sufficient to form a precipitate comprised of hemicellulose and lignin.
• the precipitate of hemicellulose and lignin is then separated from the acidic organic solvent syrup.
• the precipitate is mixed with an aqueous solvent to form a solution of solubilized hemicellulose and insoluble lignin and the insoluble lignin is separated from the solubilized hemicellulose.
• a "C1-C2 acid-miscible organic solvent” referenced above is defined in WO'042 as a non-acidic organic solvent that is miscible with acetic acid and able to form a precipitate of hemicellulose and lignin from an acetic acid solution containing the same, with the proviso only that the C1-C2 acid-miscible organic solvent is not a halogenated solvent.
• the organic solvent used has following characteristics: the solubility of sugars in the solvent must be low, and at least a subfraction of the lignin must be partially soluble in the solvent. Such solvents are slightly polar. Preferably the solubility of water in the organic solvent should be low.
• the polarity of the solvent should not be too low to effectively extract acetic acid from water.
• Suitable examples include low molecular weight alcohols, ketones and esters, such as C1-C4 alcohols, acetone, ethyl acetate, methyl acetate, and methyl ethyl ketone, and tetrahydrofuran.
• liquid / liquid separation methods are used instead of filtration in certain steps, so that viscosity limitations inherent to the filtration process are avoided.
• the solids in the concentrated hemicellulose and lignin syrup are limited to not more than about 40% by filtration-related viscosity concerns, as the C1-C2 acid-miscible organic solvent is removed by evaporation.
• the evaporation can be carried out until at least a concentration of 52% solids in the concentrated hemicellulose and lignin syrup is reached.
• the higher level of solids concentration in turn permits smaller amounts of acid and solvent to be used in subsequent purification steps.
• substantially reduced quantities of water are needed for the water washing steps, so that the costs of recovery of acid and solvent, especially the separation of water and acid mixtures, are reduced. Still other refinements and improvements are described in addition.
• the present invention relates in one aspect to a process for dealing with mixed C5/C6 sugars from a lignocellulosic biomass in a fundamentally different manner, without the need for departing from long-practiced fermentation methods for producing ethanol.
• a conventional fermentation of the hexoses in a mixed C5/C6 sugars feed is initially undertaken with the objective of minimal conversion of the pentoses to sugar alcohols.
• the hexoses in the mixed C5/C6 sugars feed are supplemented with liquefied starch prior to the hexose fermentation step, to provide improved energy utilization in a subsequent distillation step wherein a commercial grade ethanol product is separated from the pentoses in the mixed C5/C6 sugars feed and from any unconverted hexoses therein.
• a commercial grade ethanol product is separated from the pentoses in the mixed C5/C6 sugars feed and from any unconverted hexoses therein.
• minimal conversion of the pentoses present in the mixed C5/C6 sugars feed is sought in the fermentation step so that these are carried forward for further processing after the distillation.
• the remainder of the mixed C5/C6 sugars feed then undergoes an acid-catalyzed dehydration and cyclization to produce furfural from the pentoses.
• the dehydration and cyclization are accomplished with using a water-soluble acid in the presence of a low-boiling, substantially water-immiscible organic solvent.
• the furfural is extracted into an organic solvent phase comprising the low-boiling, substantially water-immiscible organic solvent, with recovery of unconverted hexose sugars and/or of valuable hexose dehydration products (for example, 5-(hydroxymethyl)furfural (or HMF) and levulinic acid) in an aqueous phase.
• High starting dry solids concentrations are achievable in certain embodiments, with nearly quantitative yields to furfural from the pentoses in a mixed C5/C6 sugars feed and with high accountability of the combined sugars in a biomass.
• the mixed C5/C6 sugars feed that is fermented derives from an upstream biomass fractionation process wherein a cellulosic component of the biomass is hydrolyzed to hexoses and a hemicellulosic component of the biomass is hydrolyzed to pentoses.
• an upstream biomass fractionation process according to any of the US'742, US'763, US'766 or US'331 applications is used to generate the mixed C5/C6 sugars stream.
• the mixed C5/C6 sugars feed that is fermented is not derived from a prior biomass fractionationation process, but is the direct hydrolyzate of a whole biomass.
• the ethanol from the hexose fermentation step is combined with ethanol from a separate starch fermentation, to provide the improved energy utilization in a subsequent distillation step wherein a commercial grade ethanol product is separated from the pentoses in the mixed C5/C6 sugars feed and from any unconverted hexoses therein.
• the hexoses in the mixed C5/C6 sugars feed are not supplemented with liquefied starch prior to the hexose fermentation step, and the ethanol from the hexose fermentation step is not recovered in a subsequent distillation step but is instead used to modify the properties of a low boiling, substantially water-immiscible organic solvent used in certain embodiments for the acid-catalyzed dehydration step and to improve the recovery of valuable hexose dehydration products in the aqueous phase, namely, 5- hydroxymethylfurfural (HMF) and levulinic acid.
• HMF 5- hydroxymethylfurfural
• the present invention relates to a method for making furfural from a mixed C5/C6 sugars feed from a lignocellulosic biomass in the absence of a preceding hexose fermentation step.
• the mixed C5/C6 sugars feed undergoes an acid-catalyzed dehydration using a water-soluble acid in the presence of a low-boiling, substantially water-immiscible organic solvent to convert the pentoses therein to furfural.
• the furfural is extracted into an organic solvent phase, with recovery of valuable hexose dehydration products (for example, 5- (hydroxymethyl)furfural (or HMF) and levulinic acid) in an aqueous phase, together with any unconverted hexoses.
• hexose dehydration products for example, 5- (hydroxymethyl)furfural (or HMF) and levulinic acid
• an upstream biomass fractionation process according to any of the US'742, US'763, US'766 or US'331 applications is used to generate the mixed C5/C6 sugars stream.
• the mixed C5/C6 sugars feed is not derived from a prior biomass fractionationation process, but is the direct hydrolyzate of a whole biomass.
• the acid-catalyzed dehydration is accomplished in a plurality of reactors in series with an addition of a low-boiling, substantially water- immiscible organic solvent upstream of each reactor in the series.
• a portion of the organic solvent is flashed overhead before a distillation step to recover furfural from the organic fraction.
• the organic fraction is catalytically decarbonylated to convert furfural to furan as described in our Patent Cooperation Treaty Application Serial No. PCT/US2014/048783, filed July 31 , 2014 for "Process for Producing Furan from Furfural from Biomass” and claiming priority from United States Provisional Patent Application Serial No. 61/864,228 filed Aug. 9, 2013 (hereafter "WO'783"), and then the furan product and the solvent are separated by distillation.
• Figure 1 is a schematic representation of a "whole biomass" process according to the first aspect, wherein a fermentation of a mixed C5/C6 sugars feed from the hydrolysis of a whole biomass precedes an acid-catalyzed dehydration with a water-soluble acid in the presence of a low-boiling, substantially water-immiscible organic solvent to convert pentoses in the mixed C5/C6 sugars feed to furfural.
• Figure 2 is a schematic representation of one embodiment of a process for accomplishing the acid-catalyzed dehydration.
• FIG. 1 a process of the present invention is schematically illustrated according to a first aspect wherein hexoses in a mixed C5 C6 sugars feed are fermented to ethanol while pentoses in the mixed C5/C6 sugars feed undergo an acid-catalyzed dehydration and cyclization to produce furfural.
• a lignocellulosic biomass 12 is combined with a water-soluble acid 14 in a digester 16, with steam 18 being added to provide heat for the digestion of the biomass 12.
• Corn kernel fiber is a readily available biomass in current corn-to-ethanol wet mills, so provides a convenient lignocellulosic biomass 12.
• Preferred water-soluble acids 14 for a whole biomass process will be those that have been historically used for producing furfural from corncobs and the like, for example, soluble inorganic acids such as sulfuric, phosphoric and hydrochloric acid; in alternate embodiments described below working with a mixed C5/C6 sugars feed from a prior fractionation method already involving an acid hydrolysis step, it will be appreciated that the preferred water-soluble acids may be or may include those already present in the aqueous sugars solution from the preceding fractionation method and, further, that the acids present may be sufficient for accomplishing the production of furfural from the pentoses and in a further optional embodiment of levulinic acid from the hexoses.
• soluble inorganic acids such as sulfuric, phosphoric and hydrochloric acid
• the water-soluble acids may be or may include C1-C2 acids selected from the group consisting of acetic acid, formic acid and mixtures of the same.
• Other acid catalysts for example, AlC hexahydrate with hydrochloric acid, may also be used.
• additional acid may be supplied as well for the formation of furfural from the pentoses and further for the production of levulinic acid from the hexoses.
• the biomass hydrolyzate 20 from digester 16 (or a hot mixed C5/C6 sugars feed from a prior fractionation method) then proceeds to a flash vessel 22 wherein excess water is flashed overhead in stream 24.
• a dewatered hydrolyzate stream 26 is then cooled to remove excess heat used for the digestion of the biomass 12 in the digester 16 as the dewatered hydrolyzate stream 26 enters the mashing, saccharification and fermentation section of the process 10.
• the stream 26 then enters a vessel 28, wherein after partial neutralization with an added base 30 (for example, ammonium hydroxide) and addition of cellulase enzymes 32 (for example, a-amylase enzyme), a liquefied mash 34 comprising a mixture of pentose and hexose sugars and oligomers as well as some non-fermentable solids is produced.
• an added base 30 for example, ammonium hydroxide
• cellulase enzymes 32 for example, a-amylase enzyme
• the liquefied mash 34 then proceeds to a fermentation vessel 36, wherein the mash 34 is combined according to conventional ethanol fermentation methods with a fermentative, ethanol-producing microorganism 38 (for example, a yeast such as saccharomyces cerevisiae, a bacteria or fungus) and additional enzymes 40 (for example, glucoamylase) to produce ethanol from the mash 34.
• a fermentative, ethanol-producing microorganism 38 for example, a yeast such as saccharomyces cerevisiae, a bacteria or fungus
• additional enzymes 40 for example, glucoamylase
• the fermentation is controlled so as to obtain minimal conversion of the pentoses in the mash 34 to sugar alcohols, so that these pentoses can be subsequently converted to furfural; in the context of a conventional saccharomyces cerevisiae fermentation, for instance, we have found that this objective can be obtained by tracking the rate of carbon dioxide production over time, and stopping the fermentation as the carbon dioxide production rate approaches zero and as the more-readily fermented hexose sugars in the mash 34 have been depleted.
• the fermentation is controlled so that at least 90 percent of the pentoses remain unconverted, while more preferably at least 95 percent of the pentoses remain unconverted, still more preferably at least 99 percent of the pentoses remain unconverted and most preferably at least 99.5 percent of the pentoses remain unconverted.
• the hexose sugars in the mash 34 can be supplemented - with any requisite adjustment in the amounts and types of enzymes added in stream 40 and other appropriate adjustments in the fermentation conditions in vessel 36 - by addition of liquefied starch via stream 42.
• the ethanol produced in vessel 36 is sufficient in itself or when combined with ethanol from other fermenters (whether in parallel processes 10 or from other operations) to be economically distilled in the absence of the ethanol that would be produced from the added liquefied starch to omit the addition of starch to fermenter 36 via stream 42.
• the ethanol produced in vessel 36 will not be recovered through distillation as a commercial grade product but will be used to modify the properties of a low boiling, substantially water-immiscible organic solvent used in certain embodiments for the acid-catalyzed dehydration step in the subsequent production of furfural, and to improve the recovery of valuable hexose dehydration products in addition to furfural, namely, 5-hydroxymethylfurfural (HMF) and levulinic acid.
• HMF 5-hydroxymethylfurfural
• a product 44 from the fermenter 36 including substantial ethanol, pentoses for the subsequent production of furfural, and certain non-fermentable solids is passed to a distillation column 46.
• the distillation of the product 44 therein provides a commercial grade ethanol product overhead as stream 48, typically and preferably being 95 pet.
• bottoms 50 comprising both the solubilized pentoses designated for producing furfural and non-fermentable solids passes to a solids-liquid separation, for example, a centrifugal separator 52.
• the solids 54 from separator 52 may be dried in a drier 56 to provide a high protein animal feed product 58, while solubilized pentoses from bottoms 50 are recovered from separator 52 in a liquid feed 60 to a subsequent production step 62 for producing a furfural product 64.
• FIG 2 a schematic representation of one such process 62 is provided, wherein the liquid feed 60 including solubilized pentoses is acid- dehydrated in a plurality of reactors in series with an addition of a low-boiling, substantially water-immiscible organic solvent upstream of each reactor in the series.
• the acid dehydration of the pentoses to furfural is continuously accomplished in three reactor stages 66 in series.
• a low- boiling, substantially water-immiscible organic solvent is added in three corresponding increments 68 upstream of the reactor stages 66, with inline static mixers 70 being used to thoroughly mix the solvent and the liquid feed 60 upstream of the first reactor stage 66 and to thoroughly mix the solvent and the partially converted liquid feed after the first and second reactor stages 66.
• Preferred low-boiling, substantially water- immiscible solvents include toluene, ethanol, tetrahydrofuran and methyl tetrahydrofuran; the toluene and tetrahydrofuran provide obvious integration options when considered in relation to the use of furfural to make furan and subsequently THF from furan, while ethanol as described herein may be produced from hexoses in a mixed C5 C6 sugars feed from a prior biomass fractionation or from hydrolysis of a whole biomass (e.g., corn kernel fiber) and thus provides additional obvious integration options and benefits.
• a whole biomass e.g., corn kernel fiber
• Interstage separators 72 between reactor stages 66 each function to recover an organic phase portion 74 comprising furfural formed by dehydration in the presence of the soluble acid catalyst added via stream 14 in the low-boiling, substantially water-immiscible organic solvent (and/or previously in a biomass fractionation process including acid hydrolysis), while aqueous phase portions 76 comprised of any unconverted five- and six-carbon sugars, salts, the water-soluble acid catalyst, 5-hydroxymethylfurfural and levulinic acid continue to a subsequent stage 66 or may be recycled for combination with liquid feed 60 at the start of the series of reactor stages 66 for further dehydration to a levulinic acid product.
• the collected organic phase portions 74 from the several interstage separators 72 are separated from any residual aqueous phase materials 78 in a decanter 80, with the decanted furfural/solvent mixture 82 proceeding to a flash vessel 84 to flash off a portion 86 of the solvent for recycle in solvent recycle stream 88.
• the remainder 90 is distilled in a distillation column 92 to remove the low-boiling, substantially water- immiscible solvent for recycle in the solvent recycle stream 88 and the furfural product stream 64.
• the decanted furfural/solvent mixture 82 is catalytically decarbonylated to convert furfural to furan as described in our WO'783 application.
• decarbonylations were run on both synthetic 5% furfural in toluene feeds and on toluene extracts of the acid-catalyzed dehydration/cyclization furfural product of a pentose-containing fraction from biomass, using a 1 % Pd Al2O3 catalyst and a 2% Pd/C catalyst at a temperature ranging from 200 to 250 degrees Celsius for the synthetic feed examples and using the same palladium on alumina catalyst at 250 degrees Celsius for the actual dehydration feeds.
• furan decarbonylation product and the solvent are then separated by simple distillation.
• furfural has a boiling point of 161 .7 degrees Celsius (compared to a boiling point of toluene at 1 10.6 deg. C)
• furan has a much lower boiling point of 31 .3 degrees Celsius and so can be separated from toluene with considerably less energy being required.
• the furan thus prepared and recovered can then be hydrogenated to produce tetrahydrofuran (THF), an important solvent and intermediate in the production of Spandex ® elastomeric polyurethane fibers and other polymers.
• THF tetrahydrofuran
• a number of catalysts and processes are known for this purpose. For example, US 2,846,449 to Banford et al. prescribe finely divided nickel, platinum or palladium in the pure state or on an inert support, with foraminous or Raney ® nickel sponge metal catalyst, and finely divided reduced nickel or kieselguhr being listed as preferred catalyst choices.
• THF has been made from non-renewable resources, though a significant amount of research has been carried out over a number of years in relation to dehydrating pentoses found in or obtained from biomass to furfural, decarbonylating the furfural to furan, and then finally hydrogenating the furan to THF.
• a mixture of water and furfural is removed overhead from the distillation column located on top of the reaction vessel, via reflux through a multistage distillation to "minimize" loss of the water-miscible organic solvent overhead, while the high boiling water-miscible organic solvent is used to keep byproducts such as humins dissolved and to prevent their deposition on the solid catalysts.
• at least a portion of the contents of the reaction vessel are pumped through a filter or screen to prevent aspiration of the solid acid catalyst, and then diluted with either aqueous feedstock solution water or simply water to precipitate the water-insoluble byproducts from solution in the high-boiling water-miscible solvent.
• toluene is preferably used as the low-boiling, substantially water-immiscible solvent for the present invention, a number of other benefits may be realized as well. Firstly, toluene is a much less expensive solvent than a high-boiling water-miscible solvent such as sulfolane.
• the toluene conveniently can be used in a subsequent process according to WO783 or may be readily separated from the furfural, while in comparison some loss of the high boiling water-miscible solvent in the distillation of the furfural/water overhead is apparently to be accepted in Corbin et al's process and while further costly high boiling solvent will likely be lost in the further steps to remove humins, the solid catalyst and salts from the bottoms. Further, the processing of the bottoms to remove humins, the solid catalyst and salts as well as the presumed regeneration of the solid acid catalyst represent substantial additional processing costs, whereas the use of a low-boiling, water-immiscible solvent permits the salts and acid catalyst to be recycled directly for further use. Finally, residual hexoses in Corbin et al's process can form additional humins, making the downstream processing and recovery of furfural more complex.

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• 2015
  • 2015-01-28 KR KR1020157025880A patent/KR20160120196A/ko not_active Application Discontinuation
  • 2015-01-28 CA CA2897613A patent/CA2897613A1/en not_active Abandoned
  • 2015-01-28 CN CN201580001288.7A patent/CN105378092A/zh active Pending
  • 2015-01-28 EP EP15725223.0A patent/EP2931906A4/en not_active Withdrawn
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