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Патент USA US2405451

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Patented Aug. 6, 1946
UNITED
‘ '
T
2,405,451
PROCESS FOR PRODUCING LOW MOLECU
LAR WEIGHT LIGNI'N DEGRADATION
PRODUCTS
Jorgen Richter Salvesen, Ralph L. Hossfeld, and
Robert J. Lovin, Wausau, Wis., assignors to
Marathon Corporation, a corporation of Wis
consin
No Drawing. Application January 22, 1945,
Serial No. 574,024
9 Claims.
(Cl. 260-124)
1
This invention is concerned with a process in
which lignin compounds are treated at elevated
temperatures and pressures in admixture with
an aqueous sodium alkaline solution, and asec
ondary alcohol.
It has been discovered that such a process,
when carried out under conditions which we will
describe herein, will give high yields of low mo
2
the pressure range of 200-250 atmospheres. In
the first case suitable quantities of the lignin
product to be degraded are mixed with the so
dium alkaline solution and the secondary alcohol
and the resulting mixture placed in a high pre°
sure bomb where it is heated with agitation. In
'the latter case, the mixture of lignin product, so
dium alkaline solution and secondary alcohol is
continuously pumped through suitable high pres
lecular weight lignin degradation products which
consist in partof compounds‘of the general type 10' sure heat exchangers into a high pressure, hold
of guaiacol, and catechol, and certain of their‘ »ing ‘vessel where the reaction is allowed to take
homologues, as well as certain neutral compounds.
We have conducted numerous experiments ac
cording to the methods of our process in which
place. The reacted mixture is ‘then continuously
removed from the system through a suitable cool
er and throttling valve. The reacted mixture is
different primary, secondary and tertiary alcohols 15 then acidi?ed whereupon the lignin degradation
products and the unconsumed secondary alcohol
were employed, and these experiments have
shown that only the primary and secondary al " are caused to separate from the aqueous portion
of the mixture and are recovered. The recov
cohols are effective in producing the desired ‘high
ered mixture of the Organic products are further
yields of low molecular weight degradation prod
ucts. The tertiary alcohol gives substantially 20 separated in the usual manner into acidic, phe
nolic and neutral fractions. These fractions are
loweryields of the lignin degradation products,
then further separated by well known methods
the yields being of .thesame order of ?magnitude
into their individual components. For example,
as those obtained in comparable experiments
we have fractionally distilled the phenolic frac
where the alcoholwas omitted as a control meas
25 tion to obtain catechol, p-methyl catechol,v
ure.
guaiacol, and p-methyl guaiacol.
When primary alcohols are employed in our
=Any suitable available lignin materials can be
process as disclosed Iin our copending'l-a'pplica
utilized in carrying out our process. The con
tion Serial‘No. ‘520,668 wehave found th'at'sub
centration of sodium alkalinity may be varied de
stantially' higher yields of low molecular weight
lignin degradation products are ‘obtained than 30 pending on the type of lignin compound employed.
have been previously disclosed ‘in the'literature
for other lignin degradation processes. How
However, we have found that most satisfactory
results are obtained if slu?iicent alkali is used
so that the ?nal pH of the heated mixture is not
ever, a. considerable amount of the primary alco
substantially less than 10.
'
hol is lost for further use in the process through
intermolceular condensation of the alcohol with 35 The temperature of operation of our process
may be varied within the range of 250° to 350°
itself, to form higher alcohols, and through con
C. However, we have found temperatures in the
version to the corresponding carboxylic acid;
vicinity of 300° C. to be optimum for maximum
When secondary alcohols are employed in our
production of lignin degradation products of the
process under conditions similar tothose in-Which
primary alcohols wereused, ‘the yields of low mo 40 type of pyrocatechol and its homologues.
The time of processing may be varied in the
lecular Weight lignin degradation vproducts are
equally large. However, contrary to expectations,
only comparatively small amounts of‘ the“ sec- > ‘
_ range of 1/2 to 6 hours, the yield of degradation,
in general, increasing with time. ‘However, We
ondary alcohol are lost through‘ conversion to ' have found that a time of heating of two hours
higher alcohols by intermolecular condensation, 45 gives good yields of the desired lignin degradation
products.
and- only very small quantities are converted ‘to
by-products greatly facilitates subsequent recov
cry of the lignin degradation products‘ and, ,in
The quantity of alcohol to be employed in the
mixture‘has been studied in the range from about
10% to 100 %" of the volume of the sodium alka~
tinuous .?ow equipment may be used provided
line lignin solution gives optimum yields‘of cate
- carboxylic acids.
The absence of these alcohol
addition, an economic advantage is " obtained 50 line lignin solution. ‘It has'beenifound that quan~
tities in the range of 25% to ‘100% of the sodium
through a decrease in the amount of'alcohol con;
alkaline solution are most useful, and that an
sumed in‘the process. In‘the carrying out ‘of our
amount equal to about 65% of the sodium alka
process, we have found that either batch'orcon
such equipment is designed to ‘operate safelyjin 55 jchol type material under the conditions of the
3
4
following examples. It has also been found that
although a relatively large proportion of alcohol
is ‘used to give the optimum yield of lignin deg
radation products, it is possible to recover in the
was then treated as outlined in Example 1, with
the exception that normal butyl was used in place
of secondary butyl alcohol in the extraction of
the aqueous phase because of its greater insolu
'
neighborhood of 90-95% of the alcohol for re-use 5 bility in the water.
The yields by weight of lignin degradation prod
in the process.
Example 1
ucts obtained were as follows:
.
600 ml. of an aqueous solution containing 93
gm~ of lignin in the form of a sodium lignosul
10
tomato, and 84 gm. of sodium hydroxide, were
mixed with 400 ml. of secondary butyl alcohol and
the mixture placed in a high pressure bomb. The
mixture was heated with agitation, at a tempera
ture of 300° C., for a period of two hours. The
cooled reaction mixture was then neutralized with
Per cent based on
original lignin
Catechols
_____________________________ __ 17.8
Monohydric phenols ____________________ __ 23.9
Neutral material _______________________ __ 39.2
Emample 4
600 m1. of a solution containing 93 gm. of lignin
in the form of sodium lignosulfonate, and 84 gm.
dilute sulfuric acid whereupon the mixture sep
of sodium hydroxide, were mixed with 400 ml. of
arates into two phases, the upper layer being an
isopropyl alcohol, and the mixture placed in a
alcoholic solution of thelignin degradation prod- high pressure bomb. The mixture was heated
nets and the lower an aqueous layer. The upper
layer containing the lignin degradation products 20 with agitation, at a temperature of 270° C., for
a period of two hours. The cooled reaction mix
was separated and combined with the secondary
ture was then treated as outlined in Example 3
butanol washings of the lower aqueous layer.
to give the following yields by weight of lignin
This butanol solution of degradation products
may be treated in known ways to obtain the vari- ,~.
_ Per' cent based
,
on
ous compounds which it contains. It has been 25 degradation products:
found suitable to ?rst neutralize the excess min
original lignin
eral acid acidity by treating with an aqueous sus
Catechols ______________ __‘ ___________ ____ 32.6
pension of calcium carbonate, then to distill oft‘
essentially all the excess alcohol, then to pourqr Monohydric phenols ___________________ __' 4.3
Neutral material __________ __' ________ _;___V
the residue in a ?ne stream into a large excess
of an aliphatic hydrocarbon solvent with vigorous
The foregoing examples are given as illustra
tions of various typical applications‘for our inven
stirring. Through such a procedure, a ?occulent
precipitate of partially degraded but amorphous
and non-distillable lignin material separatearr
leaving a solution of the low molecular weight,
distillable lignin degradation products. The low
tion. It should
other variations
within the scope
herein disclosed
molecular weight products may then be individu
ally segregated in known ways.
original lignin
_____________________________ __
Monohydric phenols ___________________ __
38
_
V
,
We claim:
'
.
,
-
1. A process for making low molecular weight
distillable organic compounds from lignin sub
stance which comprises treating a lignin sub
products so obtained were as follows:
Per cent based on
‘
be understood that numerous
and modi?cations are possible
and principles of the invention
as de?ned in the appended
claims.
The yields by weight of lignin degradatiorl‘jzl0
Catechols
5.4
‘ stance with a mixture of water, sodium alkaline
solution, and a secondary aliphatic alcohol at
}
5.4745 250° to 350° C.
‘I
2. A process for making low molecular weight
distillable organic compounds from lignin sub
Earample 2
I
stances which comprises treating a lignin sub
600 ml. of a solution containing 93 gm. of lig-_
stance with a mixture of water, sodium alkaline
nin in the form of a sodium lignin sulfonate, and :50 solution, and a secondary aliphatic alcohol in
84 gm. of sodium hydroxide, were mixed with
amounts of from 25 to 75% of the volume of the
400 ml. of secondary butyl alcohol and the mix
total mixture at 250° to 350". C., and, recovering
ture placed in a high pressure bomb. The mix
the low molecular weight compounds from the re
Neutral material ________ __\___r_ ________ __ 14.1
ture was heated with agitation, at a temperature
of 350° C., for a period of two hours. The cooled i555
reaction mixture was then treated as outlined
‘
'
V
‘
3. A process for making low molecular weight
simple distillable organic compounds from lignin
substances which comprises treating alignin‘sub
stance with a mixture of watensodium alkaline
in Example 1 to give the following yields by weight
of lignin degradation products:
Per cent based on
original lignin
action mixture.
' 60
Catechols _______________ up--. ____ _______ 14.5
Monohydric phenols- __________ __W_ ______ __ 21.8
solution, and secondarybutyl alcohol, at 250° to
350° 0., and recovering the low molecular weight
compounds from the reaction mixture.
4. A process for making low molecular weight
Neutral material ________________ -1 _____ __ 34.9
simple distillable organic compounds from lignin
Example 3
substances which comprises treating a lignosul
fonic acid compound with a mixtureof water,
~
.. -
if. 65
600 ml. of a solution containing 93 gm. of lignin
in the form of a sodium lignosulfonata'and 84
gm. of sodium hydroxide, were mixed with 400
ml. of isopropyl alcohol and placed in a high pres- ‘
sure bomb. The mixture was heated with agita- '70
tion, at a temperature of 325°’ C.-, for a periodof
two hours. The cooled reaction mixture was then
distilled to remove the unused isopropyl alcohol,
sodium alkaline solution,v and secondary butyl
alcohol, at 250° to 350° C., and recovering the low
molecular weight compounds from the reaction
mixture.
‘
1g
’
A
v
5. A process for makinglow molecular weight
simple distillable organic compounds from ‘lig
'nin substances which comprises treating-a lignin
substance with a mixture of water, sodium alka
the distillation being preferably carried out under . .linersolution ‘and a secondary aliphatic alcohol,
slight vacuum. The residue from this distillation 75 at'250° to 350° C. for a period of about 1/2 to 2
2,405,451
5
hours and recovering the low molecular weight
compounds from the reaction mixture.
6. A process for making low molecular weight
6
simple distillable organic compounds from lignin
substances which comprises treating lignosulfonic
acid compounds with a mixture of water, sodium
simple distillable organic compounds from lignin
alkaline solution, and secondary butyl alcohol,
substances which comprises treating a lignin sub
stance with a mixture of water, sodium alkaline
for a period of from 1/2 to 2 hours in the tempera
ture range of from 250° to 350° C., and recover
solution, and a secondary aliphatic alcohol, in a
ing the low molecular weight compounds from the
temperature range from 250° to 350° C. and re
reaction mixture.
9. A process for making low molecular weight
covering the low molecular weight compounds
10 simple distillable organic compounds from lignin
from the reaction mixture.
substances which comprises treating lignosulfonic
7. A process for making low molecular weight
simple distillable organic compounds from lignin
substances which comprises treating lignosulfonic
acid compounds with a mixture of water, sodium
alkaline solution, and isopropyl alcohol, for a pe
riod of from 1/2 to 2 hours in the temperature
acid compounds with a mixture of water, sodium
alkaline solution, and a lower secondary aliphatic 15 range of from 250° to 350° 0., and recovering the
low molecular weight compounds from the reac
alcohol, for a period of from 1/2 to 2 hours in the
temperature range from 250° C. to 350° 0., and
tion mixture.
__
' J ORGEN RICHTER SALVESEN.
recovering the low molecular weight compounds
from the reaction mixture.
RALPH L. HOSSFELD.
8. A process for making low molecular weight 20
ROBERT J. LOVIN.
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