U.S. patent application number 16/132321 was filed with the patent office on 2019-09-05 for utilizing a multiphase reactor for the conversion of biomass to produce substituted furans.
This patent application is currently assigned to MICROMIDAS, INC.. The applicant listed for this patent is MICROMIDAS, INC.. Invention is credited to John BISSELL, II, Brian HIGGINS, Makoto Nathanael MASUNO, Ryan L. SMITH, Alex B. WOOD.
Application Number | 20190270717 16/132321 |
Document ID | / |
Family ID | 46466824 |
Filed Date | 2019-09-05 |
![](/patent/app/20190270717/US20190270717A1-20190905-D00001.png)
United States Patent
Application |
20190270717 |
Kind Code |
A1 |
MASUNO; Makoto Nathanael ;
et al. |
September 5, 2019 |
UTILIZING A MULTIPHASE REACTOR FOR THE CONVERSION OF BIOMASS TO
PRODUCE SUBSTITUTED FURANS
Abstract
The present disclosure provides methods to produce substituted
furans (e.g., halomethylfurfural, hydroxymethylfurfural, and
furfural), by acid-catalyzed conversion of biomass using a gaseous
acid in a multiphase reactor, such as a fluidized bed reactor.
Inventors: |
MASUNO; Makoto Nathanael;
(Elk Grove, CA) ; BISSELL, II; John; (Sacramento,
CA) ; SMITH; Ryan L.; (Sacramento, CA) ;
HIGGINS; Brian; (Davis, CA) ; WOOD; Alex B.;
(Sacramento, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MICROMIDAS, INC. |
West Sacramento |
CA |
US |
|
|
Assignee: |
MICROMIDAS, INC.
West Sacramento
CA
|
Family ID: |
46466824 |
Appl. No.: |
16/132321 |
Filed: |
September 14, 2018 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15468728 |
Mar 24, 2017 |
10093638 |
|
|
16132321 |
|
|
|
|
14805321 |
Jul 21, 2015 |
9637463 |
|
|
15468728 |
|
|
|
|
14124240 |
Dec 5, 2013 |
9126964 |
|
|
14805321 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07D 307/50 20130101;
C07D 307/46 20130101 |
International
Class: |
C07D 307/50 20060101
C07D307/50; C07D 307/46 20060101 C07D307/46 |
Claims
1-83. (canceled)
84: A method for producing furfural, hydroxymethylfurfural,
halomethylfurfural, optionally substituted alkylfurfural, levulinic
acid, or formic acid, or any combination thereof in a gas-solid
phase reactor, the method comprising: feeding solid feedstock into
a gas-solid phase reactor, wherein the solid feedstock comprises
biomass or sugar, or any combination thereof; feeding gaseous acid
into the gas-solid phase reactor; wherein: (i) the solid feedstock
has less than 10% water by weight; (ii) the gaseous acid has less
than 10% water by weight; or (iii) both (i) and (ii); mixing the
solid feedstock and the gaseous acid to form a reaction mixture;
and producing furfural, hydroxymethylfurfural, halomethylfurfural,
alkylfurfural, levulinic acid, or formic acid, or any combination
thereof, from at least a portion of the solid feedstock and at
least a portion of the gaseous acid in the reaction mixture.
85: The method of claim 84, wherein the solid feedstock has between
1% and 10% water by weight.
86: The method of claim 84, wherein the reaction mixture has less
than about 10% water by weight.
87: A system for producing furfural, hydroxymethylfurfural,
halomethylfurfural, optionally substituted alkylfurfural, levulinic
acid, or formic acid, or any combination thereof, wherein the
system comprises: solid feedstock, wherein the solid feedstock
comprises biomass, sugar, or a combination thereof, gaseous acid;
and a multiphase reactor configured to receive the solid feedstock
and the gaseous acid and provide a reaction mixture comprising
producing furfural, hydroxymethylfurfural, halomethylfurfural,
alkylfurfural, levulinic acid, or formic acid, or any combination
thereof, wherein: (i) the solid feedstock has less than 10% water
by weight; (ii) the gaseous acid has less than 10% water by weight;
or (iii) both (i) and (ii).
88: The system of claim 87, wherein the solid feedstock has between
1% and 10% water by weight.
89: The system of claim 87, wherein the reaction mixture has less
than about 10% water by weight.
90: A composition, comprising: a solid feedstock, wherein the solid
feedstock comprises biomass or sugar, or a combination thereof;
gaseous acid; and furfural, hydroxymethylfurfural,
halomethylfurfural, optionally substituted alkylfurfural, levulinic
acid, or formic acid or any combination thereof; wherein: (i) the
solid feedstock has less than 10% water by weight; (ii) the gaseous
acid has less than 10% water by weight; or (iii) both (i) and
(ii).
91: The composition of claim 90, wherein the solid feedstock has
between 1% and 10% water by weight.
92: The composition of claim 90, wherein the composition has less
than about 10% water by weight.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 61/495,324 filed Jun. 9, 2011, which is
incorporated herein by reference in its entirety.
FIELD
[0002] The present disclosure relates generally to the conversion
of biomass into biofuels and chemicals. In particular, the present
disclosure relates to the production of substituted furans (e.g.,
halomethylfurfural, hydroxymethylfurfural, and furfural) by
acid-catalyzed conversion of biomass containing glycans (e.g.,
cellulose) and/or heteroglycans (e.g., hemicellulose), using a
gaseous acid in a multiphase reactor.
BACKGROUND
[0003] Efforts to reduce dependence on fossil fuels for
transportation fuel and as feedstock for industrial chemicals have
been undertaken for decades, with a particular focus on enabling
economic feasibility of renewable feedstock. Heightened efforts are
being made to more effectively utilize renewable resources and
develop "green" technologies, due to continued long-term increases
in the price of fuel, increased environmental concerns, continued
issues of geopolitical stability, and renewed concerns for the
ultimate depletion of fossil fuels.
[0004] Conventional biofuel production from renewable feedstock
employs a two-step process. In the first step, fermentable sugars
are produced from biomass, typically by enzymatic saccharification.
In the second step, the sugars are fermented into biofuels or
chemicals. This two-step process, however, presents several
technical challenges.
[0005] For example, biomass needs to be pretreated before
hydrolysis can take place to produce sugars. Digestibility of
cellulose in biomass is hindered by various physicochemical,
structural and compositional factors. Pretreating biomass helps
digest the cellulose and hemicellulose fractions of biomass by
breaking down the lignin structure and disrupting the crystalline
structures of cellulose and hemicellulose. This makes the biomass
more accessible to hydrolysis for producing sugars used in
subsequent fermentation. Common pretreatments known in the art
involve, for example, mechanical treatment (e.g., shredding,
pulverizing, grinding), concentrated acid, dilute acid, SO.sub.2,
alkali, hydrogen peroxide, wet-oxidation, steam explosion, ammonia
fiber explosion (AFEX), supercritical CO.sub.2 explosion, liquid
hot water, and organic solvent treatments. These pretreatment
options, however, are often expensive and technically difficult to
implement on a commercial scale.
[0006] Moreover, acid conversion of biomass to produce the sugars
often encounter mass transfer limitations that may reduce overall
reaction yields and limit control of product selectivity. Grinding
may improve mass transfer rates by reducing particle size; however,
for solution-phase systems, the biomass particle size may be
approximately one micron or less before mass transfer is no longer
rate-limiting. Grinding biomass to this particle size may often be
energy-intensive and commercially impractical.
[0007] Solution-phase hydrochloric acid (HCl)-catalyzed hydrolysis
of cellulose may offer high glucose yields, but commercialization
has been challenging. Technical considerations that may be
expensive to address on a commercial scale include the high
concentrations of aqueous HCl (.gtoreq.40%) used for effective
conversion and throughput under conditions of moderate temperature
hydrolysis; high energy requirements for HCl recycling due to
formation of boiling azeotropes of HCl and water at concentrations
of 20 wt %; additional energy requirements to recover HCl solvent
from the slurry cake formed from lignin that is saturated with
HCl-rich solutions; and the use of large glass-lined reactors,
which are often expensive, due to the high corrosiveness of
HCl.
[0008] Once biomass is hydrolyzed to form sugars, challenges also
exist to purify the resulting sugars and to remove hydrolysis
by-products (e.g., acetate and formate). For example, if the
cellulose used as a starting material is not pure, the sugars
produced may be harder to isolate.
[0009] Substituted furans (e.g., halomethylfurfural,
hydroxymethylfurfural, and furfural) produced from biomass may be
converted into furanic derivatives used as biofuels and diesel
additives, as well as a broad range of chemicals and plastic
materials. For example, 5-(chloromethyl)furfural can be converted
into 2,5-dimethylfuran, which may be used as a biofuel.
Additionally, 5-(chloromethyl)furfural can be converted into
5-(ethoxymethyl)furfural, which is a combustible material that may
be used as a diesel additive or kerosene-like fuel. Furanic
derivatives, however, are currently underutilized to produce
chemical commodities because the commercial production methods are
not economical.
[0010] The production of 5-(chloromethyl)furfural and
5-(hydroxymethyl)furfural from cellulose was first described in the
early 1900s; however, slow kinetics and harsh reaction conditions
make this method of biofuel production commercially
unattractive.
[0011] What is needed in the art is a method to directly prepare
biofuels and chemicals from biomass, thereby addressing some of the
challenges associated with the conventional two-step process
involving enzymatic saccharification and fermentation. What is also
needed in the art is a method to prepare substituted furans (e.g.,
halomethylfurfural, hydroxymethylfurfural, and furfural) from
biomass containing cellulose and/or hemicellulose in an efficient
and cost-effective way. Once these substituted furans are produced,
they can serves as intermediates that can be converted into to
furanic derivatives such as biofuels, diesel additives, and
plastics.
SUMMARY
[0012] The present disclosure addresses this need by providing
processes to produce substituted furans (e.g., halomethylfurfural,
hydroxymethylfurfural, and furfural) by acid-catalyzed conversion
of biomass using a gaseous acid in a multiphase reactor. The
processes disclosed herein make it possible to directly produce
substituted furans (e.g., halomethylfurfural,
hydroxymethylfurfural, and furfural) from the cellulose and/or
hemicellulose in biomass in a way that minimizes the need for
pretreating the biomass.
[0013] The present disclosure provides fast and cost-effective
processes utilizing a multiphase reactor to convert a wide range of
cellulosic feedstock into substituted furans (e.g.,
halomethylfurfural, hydroxymethylfurfural, and furfural). Other
compounds, such as levulinic acid and formic acid, may also be
produced by the processes. The processes employ a gaseous acid to
catalyze the conversion of glycans (e.g., cellulose) and/or
heteroglycans (e.g., hemicellulose) to substituted furans, such as
hydroxymethylfurfural, chloromethylfurfural, and furfural-all
within a single unit operation. Thus, the processes described
herein open up an efficient industrial process to chemicals such as
dimethylfuran, ethoxymethylfurfural, and furan dicarboxylic
acid.
[0014] In one aspect, provided is a process for producing a
substituted furan in a multiphase reactor, by: feeding biomass and
a gaseous acid into a multiphase reactor; and mixing the biomass
and the gaseous acid in the presence of a proton donor and a
solvent to form a reaction mixture, under conditions suitable to
produce a substituted furan, in which the reaction mixture has less
than 10% by weight of water.
[0015] In some embodiments, the process further includes separating
gaseous acid from the reaction mixture using a solid-gas separator;
and drying the separated gaseous acid. The solid-gas separator may
be a cyclone, a filter, or a gravimetric system.
[0016] In some embodiments that can be combined with the preceding
embodiment, the process further includes feeding the dried gaseous
acid into the multiphase reactor. In one embodiment, the multiphase
reactor is a fluidized bed reactor.
[0017] In some embodiments that can be combined with any of the
preceding embodiments, the gaseous acid is a halogen-based mineral
acid or a halogen-based organic acid. In certain embodiments, the
gaseous acid is gaseous hydrochloric acid. In other embodiments,
the gaseous acid has less than 10% by weight of water. In one
embodiment, the gaseous acid is dry. In certain embodiments, the
gaseous acid is continuously fed into the multiphase reactor.
[0018] In some embodiments that can be combined with any of the
preceding embodiments, the biomass includes glycans, heteroglycans,
lignin, inorganic salts, cellular debris, or any combination
thereof. In certain embodiments, the biomass is continuously fed
into the multiphase reactor. In other embodiments, the biomass has
less than 10% by weight of water.
[0019] In some embodiments that can be combined with any of the
preceding embodiments, the proton donor is a Lewis acid. Suitable
Lewis acids may include, for example, lithium chloride, sodium
chloride, potassium chloride, magnesium chloride, calcium chloride,
zinc chloride, aluminum chloride, boron chloride, or any
combination thereof. In other embodiments, the proton donor has
less than 10% by weight of water.
[0020] In some embodiments that can be combined with any of the
preceding embodiments, the solvent is selected from
dichloromethane, ethylacetate, hexane, cyclohexane, benzene,
toluene, diethyl ether, tetrahydrofuran, acetone, dimethyl
formamide, dimethyl sulfoxide, acetonitrile, methanol, ethanol,
isopropanol, n-propanol, n-butanol, chloroform, dichloroethane,
trichloroethane, furfural, furfuryl alcohol, supercritical carbon
dioxide, and any combination thereof. In some embodiments, the
solvent is dry. In other embodiments, the solvent has less than 10%
by weight of water.
[0021] In other embodiments that may be combined with any of the
preceding embodiments, the pressure in the multiphase reactor is
between 0.001 atm and 350 atm. In one embodiment, the pressure in
the multiphase reactor is between 0.001 atm and 100 atm. In another
embodiment, the pressure in the multiphase reactor is between 0.001
atm and 10 atm. In yet another embodiment, the pressure in the
multiphase reactor is between 1 atm and 50 atm. In yet other
embodiments that may be combined with any of the preceding
embodiments, the temperature in the multiphase reactor is between
50.degree. C. and 500.degree. C. In one embodiment, the temperature
in the multiphase reactor is between 100.degree. C. and 400.degree.
C. In another embodiment, the temperature in the multiphase reactor
is between 100.degree. C. and 350.degree. C. In yet another
embodiment, the temperature in the multiphase reactor is between
150.degree. C. and 300.degree. C. In yet another embodiment, the
temperature in the multiphase reactor is between 200.degree. C. and
250.degree. C.
[0022] In some embodiments that may be combined with any of the
preceding embodiments, the substituted furan may include
halomethylfurfural, hydroxymethylfurfural, furfural, or any
combination thereof. In certain embodiments, the substituted furan
is halomethylfurfural. In certain embodiments, the substituted
furan is hydroxymethylfurfural. In certain embodiments, the
substituted furan is furfural. In some embodiments, the
halomethylfurfural is chloromethylfurfural, iodomethylfurfural,
bromomethylfurfural, or fluoromethylfurfural. In one embodiment,
the halomethylfurfural is chloromethylfurfural. In other
embodiments, the halomethylfurfural is 5-(chloromethyl)furfural,
5-(iodomethyl)furfural, 5-(bromomethyl)furfural, or
5-(fluoromethyl)furfural. In another embodiment, the
halomethylfurfural is 5-(chloromethyl)furfural. In some embodiments
that may be combined with any of the preceding embodiments, the
reaction mixture further includes levulinic acid, formic acid,
alkylfurfural, or any combination thereof. In certain embodiments,
the reaction mixture includes levulinic acid. In certain
embodiments, the reaction mixture includes formic acid. In certain
embodiments, the reaction mixture includes alkylfurfural. In
certain embodiments, the alkylfurfural may be optionally
substituted. In one embodiment, the alkylfurfural is
methylfurfural.
[0023] Another aspect of the disclosure provides a process for
producing a substituted furan in a multiphase reactor by: feeding
biomass into a multiphase reactor; feeding a gaseous acid into the
multiphase reactor, in which the gaseous acid has less than about
10% by weight of water; and mixing the biomass and the gaseous acid
to form a reaction mixture that includes a substituted furan. In
one embodiment, the process further includes separating gaseous
acid from the reaction mixture using a solid-gas separator, and
drying the separated gaseous acid. The solid-gas separator may be a
cyclone, a filter, or a gravimetric system. In another embodiment
that may be combined with any of the preceding embodiments, the
process further includes feeding the dried gaseous acid into the
multiphase reactor. This recycles the gaseous acid used in the
process to produce the crude mixture.
[0024] In some embodiments that can be combined with any of the
preceding embodiments, the process further includes adding a proton
donor to the reaction mixture. In certain embodiments, the proton
donor is a Lewis acid. Suitable Lewis acids may include, for
example, lithium chloride, sodium chloride, potassium chloride,
magnesium chloride, calcium chloride, zinc chloride, aluminum
chloride, boron chloride, or any combination thereof. In other
embodiments, the proton donor has less than 10% by weight of
water.
[0025] In other embodiments that may be combined with any of the
preceding embodiments, the process further includes combining the
reaction mixture with a solvent, in which the solvent solubilizes
the substituted furan, and in which the combining produces a
solution that includes the substituted furan; and separating the
solution. The solvent may include dichloromethane, ethyl acetate,
hexane, cyclohexane, benzene, toluene, diethyl ether,
tetrahydrofuran, acetone, dimethyl formamide, dimethyl sulfoxide,
acetonitrile, methanol, ethanol, isopropanol, n-propanol,
n-butanol, chloroform, dichloroethane, trichloroethane, furfural,
furfuryl alcohol, supercritical carbon dioxide, or any combination
thereof. In some embodiments that may be combined with any of the
preceding embodiments, the solvent is dichloromethane, ethyl
acetate, supercritical carbon dioxide, or any combination thereof.
In some embodiments, the solvent is dry. In other embodiments, the
solvent has less than 10% by weight of water.
[0026] In some embodiments that may be combined with any of the
preceding embodiments, the solution may be separated from residual
solids using a filter or a membrane system. In yet other
embodiments that may be combined with any of the preceding
embodiments, the process further includes distilling the solution
to obtain the substituted furan. This distillation also produces a
separated solvent. In some embodiments that may be combined with
any of the preceding embodiments, the process further includes
combining the separated solvent with a second reaction mixture. As
such, the solvent may be recaptured.
[0027] In one embodiment that may be combined with any of the
preceding embodiments, the multiphase reactor is a fluidized bed
reactor. In some embodiments that may be combined with any of the
preceding embodiments, the gaseous acid is a halogen-based mineral
acid or a halogen-based organic acid. In certain embodiments, the
gaseous halogen-based mineral acid is hydrochloric acid (HCl),
hydroiodic acid (HI), hydrobromic acid (HBr), or hydrofluoric acid
(HF). In one embodiment, the gaseous halogen-based mineral acid is
hydrochloric acid (HCl). In some embodiments that may be combined
with any of the preceding embodiments, the gaseous acid is
continuously fed into the multiphase reactor.
[0028] In other embodiments that may be combined with any of the
preceding embodiments, the biomass includes glycans, heteroglycans,
lignin, inorganic salts, cellular debris, or any combination
thereof. Particulates may also be present in the biomass, including
for example clay, silica, humic materials, or any combination
thereof. In yet another embodiment that may be combined with any of
the preceding embodiments, the biomass is continuously fed into the
multiphase reactor. In other embodiments, the biomass has less than
10% by weight of water.
[0029] In other embodiments that may be combined with any of the
preceding embodiments, the pressure in the multiphase reactor is
between 0.001 atm and 350 atm. In one embodiment, the pressure in
the multiphase reactor is between 0.001 atm and 100 atm. In another
embodiment, the pressure in the multiphase reactor is between 0.001
atm and 10 atm. In yet another embodiment, the pressure in the
multiphase reactor is between 1 atm and 50 atm. In yet other
embodiments that may be combined with any of the preceding
embodiments, the temperature in the multiphase reactor is between
50.degree. C. and 500.degree. C. In one embodiment, the temperature
in the multiphase reactor is between 100.degree. C. and 400.degree.
C. In another embodiment, the temperature in the multiphase reactor
is between 100.degree. C. and 350.degree. C. In yet another
embodiment, the temperature in the multiphase reactor is between
150.degree. C. and 300.degree. C. In yet another embodiment, the
temperature in the multiphase reactor is between 200.degree. C. and
250.degree. C.
[0030] In some embodiments that may be combined with any of the
preceding embodiments, the substituted furan may include
halomethylfurfural, hydroxymethylfurfural, furfural, and any
combination thereof. In certain embodiments, the substituted furan
is halomethylfurfural. In certain embodiments, the substituted
furan is hydroxymethylfurfural. In certain embodiments, the
substituted furan is furfural. In some embodiments, the
halomethylfurfural is chloromethylfurfural, iodomethylfurfural,
bromomethylfurfural, or fluoromethylfurfural. In one embodiment,
the halomethylfurfural is chloromethylfurfural. In other
embodiments, the halomethylfurfural is 5-(chloromethyl)furfural,
5-(iodomethyl)furfural, 5-(bromomethyl)furfural, or
5-(fluoromethyl)furfural. In another embodiment, the
halomethylfurfural is 5-(chloromethyl)furfural. In some embodiments
that may be combined with any of the preceding embodiments, the
reaction mixture further includes levulinic acid, formic acid,
alkylfurfural, or any combination thereof. In certain embodiments,
the reaction mixture includes levulinic acid. In certain
embodiments, the reaction mixture includes formic acid. In certain
embodiments, the reaction mixture includes alkylfurfural. In
certain embodiments, the alkylfurfural may be optionally
substituted. In one embodiment, the alkylfurfural is
methylfurfural.
[0031] Another aspect of the disclosure provides a process for
producing halomethylfurfural, hydroxymethylfurfural, furfural, or
any combination thereof in a multiphase reactor, by: feeding
biomass into a multiphase reactor; feeding a gaseous acid into the
multiphase reactor, in which the gaseous acid has less than about
10% by weight of water; and mixing the biomass and the gaseous acid
to form a reaction mixture that includes halomethylfurfural,
hydroxymethylfurfural, furfural, or any combination thereof. In one
embodiment, the process further includes separating gaseous acid
from the reaction mixture using a solid-gas separator, and drying
the separated gaseous acid. The solid-gas separator may be a
cyclone, a filter, or a gravimetric system. In another embodiment
that may be combined with any of the preceding embodiments, the
process further includes feeding the dried gaseous acid into the
multiphase reactor. This recycles the gaseous acid used in the
process to produce the crude mixture.
[0032] In some embodiments that can be combined with any of the
preceding embodiments, the process further includes adding a proton
donor to the reaction mixture. In certain embodiments, the proton
donor is a Lewis acid. Suitable Lewis acids may include, for
example, lithium chloride, sodium chloride, potassium chloride,
magnesium chloride, calcium chloride, zinc chloride, aluminum
chloride, boron chloride, or any combination thereof. In other
embodiments, the Lewis acid has less than 10% by weight of
water.
[0033] In other embodiments that may be combined with any of the
preceding embodiments, the process further includes combining the
reaction mixture with a solvent, in which the solvent solubilizes
the halomethylfurfural, hydroxymethylfurfural, furfural, or any
combination thereof, and in which the combining produces a solution
that includes the halomethylfurfural, hydroxymethylfurfural,
furfural, or any combination thereof; and separating the solution.
The solvent may include dichloromethane, ethyl acetate, hexane,
cyclohexane, benzene, toluene, diethyl ether, tetrahydrofuran,
acetone, dimethyl formamide, dimethyl sulfoxide, acetonitrile,
methanol, ethanol, isopropanol, n-propanol, n-butanol, chloroform,
dichloroethane, trichloroethane, furfural, furfuryl alcohol,
supercritical carbon dioxide, or any combination thereof. In some
embodiments that may be combined with any of the preceding
embodiments, the solvent is dichloromethane, ethyl acetate,
supercritical carbon dioxide, or any combination thereof. In some
embodiments, the solvent is dry. In other embodiments, the solvent
has less than 10% by weight of water.
[0034] In some embodiments that may be combined with any of the
preceding embodiments, the solution may be separated from residual
solids using a filter or a membrane system. In yet other
embodiments that may be combined with any of the preceding
embodiments, the process further includes distilling the solution
to obtain the halomethylfurfural, hydroxymethylfurfural, furfural,
or any combination thereof. This distillation also produces a
separated solvent. In some embodiments that may be combined with
any of the preceding embodiments, the process further includes
combining the separated solvent with a second reaction mixture. As
such, the solvent may be recaptured.
[0035] In one embodiment that may be combined with any of the
preceding embodiments, the multiphase reactor is a fluidized bed
reactor. In some embodiments that may be combined with any of the
preceding embodiments, the gaseous acid is a halogen-based mineral
acid or a halogen-based organic acid. In certain embodiments, the
gaseous halogen-based mineral acid is hydrochloric acid (HCl),
hydroiodic acid (HI), hydrobromic acid (HBr), or hydrofluoric acid
(HF). In one embodiment, the gaseous halogen-based mineral acid is
hydrochloric acid (HCl). In some embodiments that may be combined
with any of the preceding embodiments, the gaseous acid is
continuously fed into the multiphase reactor.
[0036] In other embodiments that may be combined with any of the
preceding embodiments, the biomass includes glycans, heteroglycans,
lignin, inorganic salts, cellular debris, or any combination
thereof. Particulates may also be present in the biomass, including
for example clay, silica, humic materials, or any combination
thereof. In yet another embodiment that may be combined with any of
the preceding embodiments, the biomass is continuously fed into the
multiphase reactor.
[0037] In other embodiments that may be combined with any of the
preceding embodiments, the pressure in the multiphase reactor is
between 0.001 atm and 350 atm. In one embodiment, the pressure in
the multiphase reactor is between 0.001 atm and 100 atm. In another
embodiment, the pressure in the multiphase reactor is between 0.001
atm and 10 atm. In yet another embodiment, the pressure in the
multiphase reactor is between 1 atm and 50 atm. In yet other
embodiments that may be combined with any of the preceding
embodiments, the temperature in the multiphase reactor is between
50.degree. C. and 500.degree. C. In one embodiment, the temperature
in the multiphase reactor is between 100.degree. C. and 400.degree.
C. In another embodiment, the temperature in the multiphase reactor
is between 100.degree. C. and 350.degree. C. In yet another
embodiment, the temperature in the multiphase reactor is between
150.degree. C. and 300.degree. C. In yet another embodiment, the
temperature in the multiphase reactor is between 200.degree. C. and
250.degree. C.
[0038] In some embodiments, the halomethylfurfural is
chloromethylfurfural, iodomethylfurfural, bromomethylfurfural, or
fluoromethylfurfural. In one embodiment, the halomethylfurfural is
chloromethylfurfural. In other embodiments, the halomethylfurfural
is 5-(chloromethyl)furfural, 5-(iodomethyl)furfural,
5-(bromomethyl)furfural, or 5-(fluoromethyl)furfural. In another
embodiment, the halomethylfurfural is 5-(chloromethyl)furfural. In
some embodiments that may be combined with any of the preceding
embodiments, the reaction mixture further includes levulinic acid,
formic acid, alkylfurfural, or any combination thereof. In certain
embodiments, the alkylfurfural may be optionally substituted. In
one embodiment, the alkylfurfural is methylfurfural.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The present application can be best understood by reference
to the following description taken in conjunction with the
accompanying drawing figures, in which like parts may be referred
to by like numerals:
[0040] FIG. 1 is an exemplary reaction scheme that shows the
conversion of cellulose and hemicellulose into
5-(chloromethyl)furfural, 5-hydroxymethylfurfural, and furfural by
acid-catalyzed hydrolysis and dehydration; and
[0041] FIG. 2 depicts a block diagram for an exemplary process of
producing substituted furans (e.g., halomethylfurfural,
hydroxymethylfurfural, and furfural) in a multiphase reactor, in
which the dotted lines represent optional inputs or steps.
DETAILED DESCRIPTION
[0042] The following description sets forth numerous exemplary
configurations, processes, parameters, and the like. It should be
recognized, however, that such description is not intended as a
limitation on the scope of the present disclosure, but is instead
provided as a description of exemplary embodiments.
[0043] The following description relates to processes involving
acid-catalyzed conversion of biomass to produce substituted furans,
such as halomethylfurfural, hydroxymethylfurfural, and furfural, by
using a multiphase reactor.
Acid-Catalyzed Conversion of Biomass
[0044] Glycans and heteroglycans in biomass can be converted into
substituted furans. In some embodiments, cellulose and
hemicellulose in biomass can be converted into halomethylfurfural,
hydroxymethylfurfural, and/or furfural in the presence of an acid.
Other products, such as levulinic acid and formic acid, may also be
produced in the reaction. The acid cleaves the glycosidic bond in
glycans and heteroglycans to yield sugar and water by catalytic
hydrolysis and dehydration of the cellulose and hemicellulose. The
acid then reacts with the sugars to produce substituted furans. In
some embodiments, the acid cleaves the glycosidic bond in cellulose
and hemicellulose to yield sugar and water by catalytic hydrolysis
and dehydration of the cellulose and hemicellulose. The acid then
reacts with the sugars to produce halomethylfurfurals.
[0045] With reference to FIG. 1, in an exemplary process, cellulose
102 is hydrolyzed in the presence of a gaseous halogen-based
mineral acid 104 to produce hexose 106 (e.g., glucose, fructose),
which then undergoes dehydration in the acidic environment to
produce halomethylfurfural 108 and hydroxymethylfurfural 110.
[0046] Given the acidic reaction conditions, however,
halomethylfurfural 108 and hydroxymethylfurfural 110 may rehydrate
to produce levulinic acid 112 and formic acid 114. Among the
products formed from this exemplary reaction, halomethylfurfurals
are the preferred product because they are more reactive
intermediates for conversion into biofuels and biodiesel additives
and derivative products, compared to the other co-products.
[0047] In addition to cellulose as a starting material,
hemicellulose in the biomass can also undergo hydrolysis. With
reference to FIG. 1, hemicellulose 120 can be hydrolyzed to form
hexose 106 and pentose 122 (e.g., arabinose, xylose). Pentose 122
can be converted into furfural 124.
[0048] It should be understood that additional components may be
added to any of the reactions in the exemplary reaction scheme
depicted in FIG. 1. For example, in other exemplary embodiments, a
proton donor, a solvent, a desiccant, or any combination thereof
may be added to produce halomethylfurfural 108 and
hydroxymethylfurfural 110 from cellulose 102 in the presence of a
gaseous halogen-based mineral acid 104.
[0049] The processes described herein employ various components,
including a multiphase reactor, solid feedstock, and a gaseous
acid, to carry out the conversion of cellulose and/or hemicellulose
to produce substituted furans.
The Multiphase Reactor
[0050] A multiphase reactor is a reactor vessel that can be used to
carry out chemical reactions in two or more phases (i.e., solid,
liquid, gas). The multiphase reactor used in the processes
described herein may be a fluidized bed reactor or other multiphase
reactors. By using a multiphase reactor for the processes described
herein, a single high-pressure, high-temperature operation unit for
combined and rapid single-step may be used to directly convert
sugars from glycans and heteroglycans into biofuels and chemicals.
In some embodiments, the multiphase reactor may be used to directly
convert sugars from cellulose and hemicellulose into biofuels and
chemicals. Thus, the use of a multiphase reactors in the processes
described herein may lead to operation cost-savings since existing
methods to produce biofuels and chemicals from cellulose and
hemicellulose typically involve two steps: first, producing
fermentable sugars from lignocellulose, and then, fermenting these
sugars into biofuels and chemicals.
[0051] a) Fluidized Bed Reactors
[0052] In a fluidized bed reactor, a fluid (either a gas or a
liquid) is passed through solid particles at high velocities to
suspend the solid particles, causing the solid particles to behave
in a suspension. This phenomenon is known as fluidization.
[0053] A fluidized bed reactor may offer several advantages. For
example, fluidization enables thorough and rapid mixing of the
suspended solids around the bed, allowing for uniform heat transfer
and uniform mixing, and eliminating hot spots within the reactor
mixture. Moreover, thorough and rapid mixing minimizes the need to
pretreat biomass to access the cellulose and hemicellulose.
[0054] When a gas is used as the fluid in the reactor, high gas
phase diffusivities overcome some of the mass transfer barriers.
For example, the Schmidt number of gaseous hydrochloric acid is
lower than that of aqueous hydrochloric acid, allowing the reaction
to proceed at a faster rate. When the reaction is run at high
temperatures, the increased diffusivity is further magnified due to
low gas phase heat capacity. Thus, the combination of increased
diffusivity and high reaction temperatures can significantly reduce
reaction times.
[0055] Further, the faster reaction rate also allows the use of
smaller, more affordable reactors capable of processing the same
throughput of material, which may decrease capital costs.
Consequently, the size and capacity of handling equipment for the
reactors may also be reduced, which may further decrease capital
costs. Energy costs may also be lowered with the reduced heat
capacity, which contributes to making the processes described
herein more economically and commercially feasible. Moreover,
increasing throughput as a result of faster reaction rates affords
the ability to recycle unreacted materials. By optimizing the
reaction rate and recycling unreacted materials, the reactions may
be driven to optimal conversion and selectivity, favoring reactions
towards the substituted furans (e.g., halomethylfurfural and
hydroxymethylfurfural), while minimizing the reactions towards
other products, such as levulinic acid and formic acid.
[0056] A fluidized bed reactor also allows for continuous
operation, which confers a commercial advantage for scaling up
reactions compared to batch operations. The solid feed can be
continuously introduced into the fluidized bed reactor by using an
airlock feed valve. A fluidized bed reactor has the capacity of
handling large volumes of biomass with minimal feedstock
preparation. For example, the feedstock used in this type of
reactor only requires drying and grinding before introduction into
the reactor, thereby eliminating the need for expensive enzymatic
pretreatments.
[0057] b) Other Multiphase Reactors
[0058] Other multiphase reactors may be used to achieve thorough
and rapid mixing of the solids with gas. For example, plug-flow
reactors may be used. Other methods of mixing may also be employed,
such as mechanical mixing and gravity. These methods of mixing may
be independent of gas flow rates. For example, mechanically-driven
method for mixing may be provided by an auger or agitation
system.
The Feedstock
[0059] The feedstock used in the processes described herein
includes biomass. Biomass can be plant material made up of organic
compounds relatively high in oxygen, such as carbohydrates, and
also contain a wide variety of other organic compounds.
Lignocellulosic biomass is a type of biomass that is made up of
cellulose and/or hemicellulose bonded to lignin in plant cell
walls.
[0060] The feedstock may originate from various sources. For
example, in some embodiments, the feedstock may originate from
waste streams, e.g., municipal wastewater, pulp waste, food
processing plant waste, restaurant waste, yard waste, forest waste,
biodiesel transesterification waste, and ethanol process waste. In
other embodiments, suitable feedstock may include corn stover, rice
hulls, rice straw, wheat straw, paper mill effluent, newsprint,
municipal solid wastes, wood chips, forest thinings, slash,
miscanthus, switchgrass, sorghum, bagasse, manure, wastewater
biosolids, green waste, and food/feed processing residues. In yet
other embodiments, the feedstock may be fructose or glucose. Any
combination of the feedstock described above may also be used as a
starting material for the processes described herein.
[0061] The processes described herein can handle feedstock that is
heterogeneous in nature, without increasing the occurrence of side
products, such as alkoxymethylfurfurals that may be formed from
cellular debris containing nucleophilic alcohols. The biomass used
may have materials such as, for example, particulates, lignin,
inorganic salts, and cellular debris. Particulates may include, for
example, clays, silica, and humic materials. In some embodiments,
the lignin content of the biomass may be less than or equal to
about 60%. In some embodiments, inorganic salts may include sulfate
or carbonate salts.
[0062] The biomass may further include glycans (e.g., cellulose,
fructose, glucose, oligomeric starches) as well as fatty acids. It
should also be understood, however, that although the processes
described herein are well-suited to handling heterogeneous
feedstock, pure or relatively pure cellulose and/or hemicellulose
may be also used.
[0063] In some embodiments, the feedstock contains less than 10%,
less than 9%, less than 8%, less than 7%, less than 6%, less than
5%, less than 4%, less than 3%, less than 2%, less than 1% water,
less than 0.1%, less than 0.01%, or less than 0.001% (wt/wt basis).
In yet other embodiments, the feedstock contains between 1-10%,
between 2-10%, between 2-4%, between 1-2%, between 0.01-2%, or
between 0.001-2% water (wt/wt basis).
The Gaseous Acid
[0064] The acid used in the processes described herein is in a
gaseous state. As used herein, the term "gaseous acid" refers to
any acid that can go into the gaseous state.
[0065] In some embodiments, the gaseous acid is dry. As used
herein, the term "dry" refers to a substance with a water content
lower than its azeotrope concentration.
[0066] In other embodiments, the gaseous acid contains less than
10%, less than 9%, less than 8%, less than 7%, less than 6%, less
than 5%, less than 4%, less than 3%, less than 2%, less than 1%
water, less than 0.1%, less than 0.01%, or less than 0.001% (wt/wt
basis). In yet other embodiments, the gaseous acid contains between
1-10%, between 2-10%, between 2-4%, between 1-2%, between 0.01-2%,
or between 0.001-2% water (wt/wt basis). The gaseous acid is
undissociated when fed into the multiphase reactor, and dissociates
upon adsorption to the glycans and/or heteroglycans in the
biomass.
[0067] The acid employed may either be halogen-based mineral acids
or halogen-based organic acids. In one embodiment, any
halogen-based mineral acid may be used. Examples may include
hydrochloric acid (HCl), hydrofluoric acid (HF), hydrobromic acid
(HBr), and hydroiodic acid (HI). In another embodiment, any
halogen-based organic acid that can induce hydration and ring
cyclization to form the substituted furans may also be used. In
some embodiments, any halogen-based organic acids that can induce
hydration and ring cyclization to form the halomethylfurfural may
be used. Suitable halogen-based organic acids may include, for
example, trifluoroacetic acid (TFA). In certain embodiments, a
halogen-based acid may be used.
[0068] The concentration of the gaseous acid used in the processes
described herein may vary. In some embodiments, the concentration
of the gaseous acid is less than or equal to 8.7M. In other
embodiments, the concentration of the gaseous acid is less than or
equal to 2.4M. In other embodiments, the concentration of the
gaseous acid is less than or equal to 0.2M. In other embodiments,
the concentration of the gaseous acid is less than or equal to
0.02M. In other embodiments, the concentration of the gaseous acid
is between 0.0001M and 8.7M. In other embodiments, the
concentration of the gaseous acid is between 2.4M and 8.7M. In
other embodiments, the concentration of the gaseous acid is between
0.2M and 2.4M. In other embodiments, the concentration of the
gaseous acid is between 0.02M and 0.2M. In other embodiments, the
concentration of the gaseous acid is between 0.0001M and 0.02M.
[0069] The processes described herein may further include
separating the gaseous acid from the reaction mixture using a
solid-gas separator, such as for example a cyclone, a filter, or a
gravimetric system. Additionally, the processes may further include
drying the separated gaseous acid, and returning the dried gaseous
acid to the reactor. In some embodiments, drying a substance refers
to removing water from a substance so that its water content is
lower than its azeotrope concentration. In other embodiments,
drying a substance refers to removing water from a substance so
that its water content is less than 10%, less than 9%, less than
8%, less than 7%, less than 6%, less than 5%, less than 4%, less
than 3%, less than 2%, less than 1% water, less than 0.1%, less
than 0.01%, or less than 0.001% (wt/wt basis). In yet other
embodiments, drying a substance refers to removing water from a
substance so that its water content is between 1-10%, between
2-10%, between 2-4%, between 1-2%, between 0.01-2%, or between
0.001-2% water (wt/wt basis).
The Proton Donor
[0070] A proton donor may be added to the reaction mixture. In some
embodiments, the proton donor is a Lewis acid. In other
embodiments, the proton donor is non-nucleophilic. In yet other
embodiments, the proton donor may be soluble in the reaction
mixture under the reaction conditions described herein. In yet
other embodiments, the proton donor may have a pKa value less than
the gaseous acid used in the reaction. The Lewis acid used as the
proton donor may complex with the gaseous acid in the reaction to
form a superacid. As used herein, a "superacid" is an acid with a
pKa less than the pKa of pure sulfuric acid. Any combinations of
the proton donors described above may also be used.
[0071] In some embodiments, the proton donor may be selected from
lithium chloride, sodium chloride, potassium chloride, magnesium
chloride, calcium chloride, zinc chloride, aluminum chloride, boron
chloride, and any combination thereof. In one embodiment, the
proton donor may be calcium chloride, aluminum chloride, or boron
chloride. In one embodiment, the proton donor is aluminum chloride,
or in the case that multiple proton donors are used, at least one
of the proton donors is aluminum chloride.
[0072] In some embodiments, the proton donor contains less than
10%, less than 9%, less than 8%, less than 7%, less than 6%, less
than 5%, less than 4%, less than 3%, less than 2%, less than 1%
water, less than 0.1%, less than 0.01%, or less than 0.001% (wt/wt
basis). In other embodiments, the proton donor contains between
1-10%, between 2-10%, between 2-4%, between 1-2%, between 0.01-2%,
or between 0.001-2% water (wt/wt basis).
The Solvent
[0073] A solvent may be added to the reaction mixture. Suitable
solvents may include, for example, dichloromethane, ethylacetate,
hexane, cyclohexane, benzene, toluene, diethyl ether,
tetrahydrofuran, acetone, dimethyl formamide, dimethyl sulfoxide,
acetonitrile, methanol, ethanol, isopropanol, n-propanol,
n-butanol, chloroform, dichloroethane, trichloroethane, furfural,
furfuryl alcohol, or supercritical carbon dioxide. In one
embodiment, the solvent is dichloromethane or dichloroethane. Any
combination of the solvents described above may also be used
[0074] In some embodiments, the solvent is dry. In other
embodiments, the solvent contains less than 10%, less than 9%, less
than 8%, less than 7%, less than 6%, less than 5%, less than 4%,
less than 3%, less than 2%, less than 1% water, less than 0.1%,
less than 0.01%, or less than 0.001% (wt/wt basis). In yet other
embodiments, the solvent contains between 1-10%, between 2-10%,
between 2-4%, between 1-2%, between 0.01-2%, or between 0.001-2%
water (wt/wt basis).
Producing Substituted Furans (e.g., Halomethylfurfural,
Hydroxymethylfurfural, and Furfural)
[0075] The processes described herein may be employed to produce
substituted furans from biomass containing glycans and/or
heteroglycans. In some embodiments, the processes described herein
may be employed to produce halomethylfurfural,
hydroxymethylfurfural, and/or furfural from biomass containing
cellulose and/or hemicellulose. Other co-products may include
levulinic acid, formic acid, and optionally substituted
alkylfurfural (e.g., methylfurfural).
[0076] a) Feeding in the Biomass and Gaseous Acid
[0077] With reference to FIG. 2, in one embodiment, gaseous
hydrochloric acid (HCl) 202 and solid biomass 204 is continuously
fed into fluidized bed reactor 200. In this exemplary embodiment,
hydrochloric acid (HCl) 202 has less than 0.001% by weight of
water. In other exemplary embodiments, the amount of the gaseous
acid may have different amounts of water, for example, less than
10% by weight of water. In reactor 200, the gaseous acid and
feedstock is fed into the side of the reactor. It should be
recognized, however, that any combination of side inputs, bottom
inputs, and top inputs may be used, depending on the type of
multiphase reactor used.
[0078] Gaseous HCl 202 is fed into reactor 200 at high velocities
to create an upward-flowing stream of gas that suspends solid
biomass 204. Fluidization allows for uniform mixing between the
acid and biomass. Solid biomass 204 is hydrolyzed and dehydrated in
the presence of gaseous HCl 202 to yield chloromethylfurfural,
hydroxymethylfurfural, and furfural.
[0079] b) Product Selectivity
[0080] As discussed above, the substituted furans may rehydrate in
the acidic reaction conditions to produce levulinic acid and formic
acid, which are often considered lower-valued products in the
context of biofuel production. In some embodiments,
halomethylfurfural and hydroxymethylfurfural may rehydrate in the
acidic reaction conditions to produce levulinic acid and formic
acid. Thus, this possibility of rehydration presents a challenge to
commercial use of the processes for biofuel production.
[0081] The processes described herein favor the formation of
substituted furans (e.g., halomethylfurfural and
hydroxymethylfurfural) over levulinic acid and formic acid. Without
wishing to be bound by any theory, a reaction at higher
temperatures may be driving dehydration faster than rehydration. As
observed based on the measured activation energy and other kinetic
parameters, the hot gas phase system described herein yields better
product selectivity. The rate of hexose dehydration to substituted
furans (e.g., halomethylfurfural) may be more sensitive to
temperature than the subsequent rehydration to levulinic acid and
formic acid, whereas the rate of rehydration may be more sensitive
to acid concentration than may be the production of substituted
furans (e.g., halomethylfurfural). Running the reaction at low acid
concentrations and at high temperatures may drive product
selectivity, favoring the substituted furans (e.g.,
halomethylfurfural and hydroxymethylfurfural) over levulinic acid
and formic acid. These reaction conditions may be achieved in a gas
phase system, as described herein.
[0082] c) Reaction Conditions
[0083] The reactor temperature range may be between the temperature
at which little to no dehydration of glucose would occur and the
temperature at which pyrolysis starts to take over. In some
embodiments, the temperature in the multiphase reactor is between
50.degree. C. and 500.degree. C. In other embodiments, the
temperature in the multiphase reactor is between 100.degree. C. and
400.degree. C. In other embodiments, the temperature in the
multiphase reactor is between 100.degree. C. and 350.degree. C. In
yet other embodiments, the temperature in the multiphase reactor is
between 150.degree. C. and 300.degree. C. In yet other embodiments,
the temperature in the multiphase reactor is between 200.degree. C.
and 250.degree. C.
[0084] The higher reaction temperatures used in the processes
described herein increases the reaction yield because lignin may
trap gaseous acids at low temperatures. When trapped in lignin, the
acid is less available to react with the biomass; however, this
inefficiency may be mitigated at higher reaction temperatures
because heat drives acid from the lignin and prevents the acid from
binding to the lignin. Reduced carry-over of acid in lignin also
creates process cost-savings because less acid is lost for use as a
solvent and/or catalyst and less acid is needed to replenish the
system. Moreover, running the processes at higher temperatures may
reduce the formation of poly-halogenated phenyls.
[0085] The reactor pressure may range between 0.001 atm to 350 atm.
In some embodiments, the processed described herein is performed in
a vacuum. In other embodiments, the pressure in the multiphase
reactor is between 0.001 atm and 200 atm. In other embodiments, the
pressure in the multiphase reactor is between 0.001 atm and 100
atm. In yet other embodiments, the pressure in the multiphase
reactor is between 0.001 atm and 10 atm. In yet other embodiments,
the pressure in the multiphase reactor is between 1 atm and 50 atm.
In yet other embodiments, the pressure in the multiphase reactor is
between 1 atm and 10 atm.
[0086] In some embodiments, the reaction mixture inside the
multiphase reactor has less than 10%, less than 9%, less than 8%,
less than 7%, less than 6%, less than 5%, less than 4%, less than
3%, less than 2%, less than 1%, less than 0.05%, less than 0.01%,
less than 0.005%, or less than 0.001% by weight of water. In
certain embodiments, the reaction mixture inside the multiphase
reactor has between 1% and 10%, between 2% and 10%, between 2% and
4%, between 1% and 5%, between 1% and 2%, between 0.1% and 2%,
between 0.01% and 2%, or between 0.001% and 2% water (wt/wt
basis).
[0087] To achieve the water content in the reaction mixture
described above, reactants and/or reagents (e.g., feedstock,
gaseous acid, proton donor and/or solvent) with less than 10% by
weight of water may be used. Desiccants may also be added to the
multiphase reactor. For example, in some embodiments, molecular
sieves may be added to the multiphase reactor to sequester water
from the reaction mixture. In certain embodiments, reactants and/or
reagents with less than 10% by weight of water and desiccants may
be used to control the water content of the reaction mixture.
[0088] d) Solid/Gas Separation
[0089] When the gas and the solids reach the top of reactor 200
(i.e., the end of the reactor), crude reaction mixture 206 exits
due to the pressure difference inside and outside the reactor. It
should be recognized, however, in reactor systems that are not
driven by pressure, movement of the particular matter solids and
their exit from the reactor may be driven by gravity and/or
mechanical means, e.g., auger systems and/or agitation.
[0090] On exit, crude reaction mixture 206 is separated into
gaseous HCl 220 and solid mixture 208 containing
chloromethylfurfural. It should be understood that the solid
mixture may include halomethylfurfural (corresponding to the acid
employed), hydroxymethylfurfural, and furfural. Any solid-gas
separators known in the art may be used, for example, a cyclone, a
filter, or a gravimetric system. Any combination of the solid-gas
separators described above may also be used.
[0091] Gaseous HCl 220 is then passed through a desiccant to remove
any water. The use of a desiccant in the processes described herein
presents a cost advantage over acid separation by azeotrope
shifting, which is energy intensive and expensive. Rather than
relying on phase changes for separation, which may lead to
azeotropic effects in aqueous acid solutions, the use of a
desiccant allows water to change its affinity for gaseous acid to
the desiccant material, enabling more efficient separation.
[0092] Dried gaseous HCl 222 is returned to reactor 200. Thus, the
acid can be recaptured and recycled back into the system.
[0093] e) Solid/Liquid Separation
[0094] Solid mixture 208 is combined with solvent 210 to drive the
reaction equilibrium towards chloromethylfurfural and
hydroxymethylfurfural. Combining solvent 210 with solid mixture 208
produces mixture 212, which contains a solution of the products
(e.g., chloromethylfurfural, hydroxymethylfurfural, and furfural)
and remaining solids, which contain unreacted starting materials.
The components of the unreacted starting materials may include, for
example, lignin, grit, minerals, and salts. Unreacted cellulose and
hemicellulose may also be present.
[0095] Any solvent known in the art suitable to solubilize the
substituted furans may be used. Suitable solvents may include, for
example, dichloromethane, ethylacetate, hexane, cyclohexane,
benzene, toluene, diethyl ether, tetrahydrofuran, acetone, dimethyl
formamide, dimethyl sulfoxide, acetonitrile, methanol, ethanol,
isopropanol, n-propanol, n-butanol, chloroform, dichloroethane,
trichloroethane, furfural, furfuryl alcohol, or supercritical
carbon dioxide. Any combinations of the solvents described above
may also be used.
[0096] Any solid-liquid separation methods known in the art, such
as a filter or membrane system, can be employed to separate mixture
212 into solution 214 (containing the products), and remaining
solids 218 (containing unreacted starting materials). Remaining
solids 218 can be optionally recycled and fed back into reactor
200, as shown in FIG. 2. This optional solids recycling step can
improve overall reaction yield.
[0097] f) Isolating Reaction Products
[0098] To isolate reaction products 224, solution 214 undergoes
distillation or any other standard separation methods known in the
art. Distillation produces separated solvent 216, which may be
recycled in the solvent quench, as depicted in FIG. 2. Reaction
products 224 collected from the distillation may include
substituted furans (e.g., halomethylfurfural,
hydroxymethylfurfural, furfural), levulinic acid, and formic
acid.
[0099] In other embodiments, the isolated substituted furans can be
further processed into other furanic derivatives for biofuels,
diesel additives, or plastics. In some embodiments, the isolated
halomethylfurfural and hydroxymethylfurfural can be further
processed into other furanic derivatives for biofuels, diesel
additives, or plastics. For example, chloromethylfurfural may be
converted into dimethylfuran and ethoxymethylfurfural.
[0100] In yet other embodiments, the isolated levulinic acid can be
used to in applications that may include, for example, cleaning
solvents, coupling agents in liquid formulations, plasticizers,
polyols for polyurethane materials, polyester thermosets,
thermoplastics, agricultural chemicals, polymer precursors and
plastics, synthetic rubbers, pharmaceutical intermediates,
photosensitizers, precursor to other chemical commodities, and in
cigarettes.
[0101] As used herein, the term "about" refers to an approximation
of a stated value within an acceptable range. Preferably, the range
is +/-10% of the stated value.
EXAMPLES
[0102] The following Examples are merely illustrative and are not
meant to limit any aspects of the present disclosure in any
way.
Example 1: Preparation of 5-(chloromethyl)furfural,
5-(hydroxymethyl)furfural, and Furfural from Lignocellulosic
Biomass
[0103] Lignocellulosic biomass originating from municipal
wastewater from Davis (CA) is obtained and fed through a side-input
into a 2000-L fluidized bed reactor at a rate of 50 kg/minute.
Gaseous hydrochloric acid is fed through another side-input into
the reactor at a rate of 4,000 L/min. The temperature inside the
reactor is approximately 220.degree. C., and the pressure inside
the reactor is approximately 15 atm.
[0104] Fluidization occurs inside the reactor, allowing for
thorough and uniform mixing of the sludge and gaseous acid. After
two minute residence times, the crude reaction mixture of gas and
solids reach the top of the reactor, and exit the reactor due to
the pressure difference inside (about 15 atm) and outside of the
reactor (about 4 atm). As the gas and solids leave the reactor, the
crude reaction mixture is separated using a cyclone into gaseous
hydrochloric acid and a solid/liquid mixture. A sample of the solid
mixture is obtained and analyzed by liquid chromatography-mass
spectrometry (LCMS). The solid mixture contains
5-(chloromethyl)furfural, 5-(hydroxymethyl)furfural, and furfural.
Additionally, some amounts of levulinic acid and formic acid are
observed in the reaction mixture.
[0105] The gaseous hydrochloric acid is passed through a desiccant
to remove water. This dried gaseous hydrochloric acid is fed back
into the fluidized bed reactor.
[0106] The solid/liquid mixture is mixed in line with
dichloromethane to produce a mixture containing both solids, and an
organic solution. This mixture is then filtered. Samples of the
retentate solids and the permeate solution are obtained and
analyzed by LCMS. The solution permeate contains
5-(chloromethyl)furfural, 5-(hydroxymethyl)furfural, and
furfural.
[0107] The solution is transferred to a distillation apparatus to
isolate the reaction products. The fractions are collected and
analyzed by LCMS. 5-(chloromethyl)furfural,
5-(hydroxymethyl)furfural, and furfural are obtained in high
purity. The reaction also produces small quantities of levulinic
acid and formic acid.
Example 2: Production of 5-(chloromethyl)furfural (CMF) from
Fructose
[0108] To a clean, dry 350 ml pressure-sealed round bottomed flask
equipped with a magnetic stir bar was added granulated fructose
(0.75 g, 4.16 mmol). The flask was then placed in an inert argon
atmosphere and dry calcium chloride (5.6 g, 50.4 mmol) and aluminum
trichloride (0.119 g, 0.832 mmol) were added and the solids
suspended in 1,2-dichloroethane (75 ml). The reaction mixture was
removed from the inert atmosphere and gaseous hydrochloric acid (0
wt % water) was bubbled into the solution until gas began to fume
from the flask. The flask was then sealed and placed in a
pre-heated oil bath set to 85.degree. C. and allowed to stir for 1
hour. The reaction mixture was then allowed to cool to room
temperature. The solids were filtered through filter paper, and
diluted to 100 mL of solvent. Volumetric analysis using a CMF flame
ionization detector (FID)-standard curve indicated a 2.1 mg/ml
concentration of CMF. The reaction yielded a total of 210 mg of CMF
(35% yield).
* * * * *