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Description  |
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BACKGROUND OF THE INVENTION
This invention relates to a process for the production of optionally foamed
polyurethane plastics, particularly shaped articles, using certain
denatured biomasses as reactive fillers. The fillers in question comprise
biomasses based on microorganisms and the derivatives and decomposition
products of microorganisms, particularly biologically purified sludges
which have been deoderized and irreversibly denatured by reaction with
isocyanates and/or carbonyl compounds and compounds capable of aminoplast
and/or phenoplast formation.
In biological purification plants, organo-chemical effluent impurities are
degraded, i.e. biologically eliminated, by means of microorganisms.
Under the conditions in purification plants, microorganisms multiply to a
particularly marked extent producing a quantity of biomass consisting
mainly of bacteria in the "activated sludge basin" of the purification
plant which increases daily by from about 3 to 4% by weight, so that
although some of the microorganisms die, the quantity of bacteria doubles
in from 3 to 4 weeks. Accordingly, some of the biomass has to be
continuously removed from the activated sludge basin in the form of
"surplus activated sludge" in order to maintain optimal conditions for
microbial effluent purification. Thus, biomasses accumulate worldwide in
extremely large and ever-increasing quantities in the fully biological
purification of industrial and communal effluents. In the Federal Republic
of Germany alone, about two million tons (expressed as dry weight) per
year of these protein-containing biomasses are presently either being
dumped or burned. Also, the necessary removal of water from activated
sludges still remains a problem because, under the sedimentation
conditions normally applied in purification plants, the activated sludge
to be removed contains only about 1% by weight of microbial dry mass. In
conventional centrifuges the solids content of the sludge may only be
concentrated to from 7 to 9% by weight. Even where polyelectrolytes are
added and centrifuges and decanters are used, the solids content may be
increased only to from 12 to 15% by weight.
Even in these low concentrations, activated sludges have a pronounced gel
structure and a relatively high viscosity due to the pronounced chemical
and physical binding of the water to the microorganisms. For this reason,
conventional filtration is impossible without specialized treatment.
Filtration is also complicated by the fact that bacteria cells attract one
another and form common, slimy shells resulting in the formation of tacky
flakes.
Another problem is that, as soon as it is isolated from the settling basin,
the excess bacterial sludge immediately begins to putrefy and give off an
intolerable odor. Even anhydrous activated sludge powder dried at
110.degree. C. has a very unpleasant odor and continues to putrefy on
becoming moist. The presence of pathogenic germs remains a problem.
For these reasons, the composting of the treated sludge or its direct use
as a fertilizer in agriculture are possible only to a limited extent. Even
today, therefore, the elimination and utilization of treated sludges
involve considerable ecological problems which, despite all efforts, have
not yet been solved satisfactorily.
Two new processes have been developed which enable various biomasses based
on microorganisms or metabolism and/or decomposition products thereof,
including in particular the above-described treated sludges from
biological treatment plants, to be worked-up in surprisingly simple and
economic manner. These work-up processes are the subject of separate
applications and will be described in detail later. In the present
context, "working-up" means that the biomasses are concentrated,
irreversibly denatured, deodorized and, in this way, made available for
utilization in the plastics industry.
DESCRIPTION OF THE INVENTION
The present invention relates to a process for the production of optionally
cellular polyurethane plastics by the isocyanate polyaddition process
comprising the reaction of:
(A) a polyisocyanate;
(B) a reactive organic filler;
(C) a low molecular weight and/or relatively high molecular weight compound
containing isocyanate-reactive hydrogen atoms; and
(D) optionally blowing agents, catalysts and other known additives;
wherein the reactive organic filler comprises a biomass based on
microorganisms and metabolism and or decomposition products thereof which
has been irreversibly denatured and deodorized by reaction with
isocyanates and/or by reaction with carbonyl compounds and compounds
capable of aminoplast and/or phenoplast formation.
In the context of the present invention, "biomasses" are understood to be
biosystems of microorganisms such as prokaryontae and eurkaryontae.
Examples of such biosystems include: bacteria, yeasts, protozoa and other
single-cell microorganisms, fungi, algae, etc., which may be present in
the divided state, dormant state, in a state of partial or complete cell
death or which may already be in the process of enzymatic decomposition or
decomposition by foreign cultures. Some examples of such biosystems which,
after being denatured are suitable for the reactive filler component of
the process of the invention include:
1. Biomasses of microorganisms from biological purification plants.
2. Biomasses of the type which accumulate:
(a) in processes for recovering products of the primary metabolism, i.e.
for example, in the biotechnical production of ethanol, butanol, acetone,
citric acid, lactic acid, tartaric acid, simple aliphatic carboxylic
acids, amino acids, etc.;
(b) in technical fermentation processes for the production of products of
the secondary metabolism, for example in the production of antibiotics,
vitamins, growth hormones, steroid hormones, alkaloids, etc.;
(c) in processes for recovering cell constituents, such as enzymes, nucleic
acids or polysaccharides; and
(d) in processes for producing yeasts, for example for baking purposes, for
alcoholic fermentation or for recovering proteins from methane, petroleum
and methanol.
3. Biomasses of the type which accumulate in biotransformation processes,
i.e. in processes where microorganisms are used as catalysts for
organochemical reactions, such as oxidation, reduction, decarboxylation,
phosphorylation, amination, deamination, acetylation, deacetylation
reactions, etc.
Biomasses preferably used for the process of the invention include:
1. Biomasses from biological plants for the purification of industrial and
communal effluents. Such biomasses consist of numerous types of bacteria,
algae and fungi which function optimally at a P:N:C ratio of about 1:5:100
and which are known as omnivores. The biomasses from purification plants,
which are also known as "activated sludges" may be used in the process of
the present invention even when they contain traces of mercury, cadmium,
zinc, iron, chromium and/or lead ions.
2. A variety of yeasts (fungi) from technical processes, for example from
alcoholic fermentation processes.
3. Biomasses from the production of acetic acid, lactic acid, citric acid
or tartaric acid and also from bacterial cultures fermenting through
enzymatic processes.
4. Defective batches of yeast cultures.
5. Biomasses from the production of proteins based on various hydrocarbon
sources, such as petroleum, paraffin cuts, methane or methanol.
Particularly suitable biomasses of this type are biomasses based on
certain yeast cells from industrial installations for the production of
protein from petroleum fractions and defective parts of such biomasses.
Such biomasses, particularly suitable for the process of the invention,
are biomasses of single-celled microorganisms consisting of bacterial
mixed cultures. Other suitable biomasses are biomasses of pseudomonas
bacteria which are cultivated in fermenters at about 37.degree. C. and
from which high-protein feeds may be produced using methanol as the carbon
source.
6. Biomasses from the production of penicillin, for example Penicillium
notatum and Penicillium chrysogenum.
7. Biomasses from the final stage of the production of tetracycline
(streptomycetes), biomasses from filament-like bacteria from the
production of isiomycin (micromonospora) and other types of streptomyces.
8. Biomasses based on various other bacteria and fungi, of the type
described in detail in co-pending U.S. patent application Ser. No. 84,002
pending Group 170 and numerous other microbial biomasses of the type
described in the literature (cf. Synthesis 4, 120-134 and 147-157, 1969).
These biomasses may consist of pure cultures and, of course, also of mixed
cultures, i.e. of cultures which have been infected during fermentation
processes and are therefore unusable. Such cultures themselves may contain
or even be mixed with, for example, dead cells of vegetable origin or cell
ingredients such as hemi-celluloses.
9. Algae, such as blue algae, green algae (for example chlorella), diatoms,
conjugatae, flagellar algae, brown algae and red algae, and also protozoa.
10. Mixed cultures of various bacteria, fungi and algae and also cultures
of biomasses which are infected with other types of fungi, bacteria, etc.
and which have a complex composition. Examples of such mixed cultures are
cultures of the type grown in open air and in moist form on spent residues
in the process of decomposition of nutrient media such as gelatin,
molasses, starches and other polysaccharides, and also on
protein-containing, still-living or even already-decomposing algae.
11. Digested sludges and biosludges of various types and also biomasses
containing large amounts of Escherichia coli and/or various suspended
vegetable substances.
12. Biomasses from anaerobic (intensive) digestion processes;
refuse/purified sludge composting products, for example from thermophilic
digestion processes (aerobic-thermophilic processes); products obtained by
the aerobic composting of purified sludge by the quick-rotting process;
microbially infested fibrous sludges; sludges from the food and
luxury-food industries, such as sludges from dairies and abattoirs; and
biosludges which have been dried and dumped.
Mixtures of different biomasses may be used in the process of the
invention. Suitable biomasses may also contain a variety of different
impurities, for example, heavy metal salts, plant protection agents,
antibiotics and other organic or inorganic chemicals.
Fillers particularly preferred for the process of the invention are those
based on aqueous or dried powder-form, activated sludges from industrial
and communal purification plants described above. These activated sludges
do not have a defined composition, but instead consist of many types of
bacteria, fungi and protozoa, depending on the contamination of the
effluent and the biological conditions. Some examples of the many types of
bacteria, fungi and protozoa contained in these sludges include:
aerobacter aerogenes, Corynebacterium laevaniformas, Paracolobactrum
aerogenoides, Escheria intermedium, Escheria faecale, Flavobacteria,
Pseudomonas, Nitrosomonas and Nitrobacter geni and also Shaerotilus natens
and white sulfur bacteria. In addition, enzymes, ferments and algae may
also be present.
All the above-mentioned biomasses contain a variety of compounds containing
H-acid groups which are capable of entering into polyaddition and
polycondensation reactions with carbonyl compounds, aminoplast and
phenoplast formers and isocyanates (cf. for example "Handbuch der
Frischwasser und Abwasserbiologie", Volume II, page 620 (1960) by H.
Lubmann). Examples of suitable compounds containing H-acid groups include:
proteins such as lipoproteins and glycoproteins as constituents of
enzymes; the enzymes themselves such as glucose oxidase, catalase, glucose
isomerase, invertase, lactase, naringinase, lipases, asparaginases,
.alpha.-amylases and glycoamylases, cellulases, lysozymes, propteases,
etc.; nucleoproteins, ribonucleic acids and deoxyribonucleic acids;
phosphatides, particularly inositol phosphatide, colamine cephalin and
serine sephalin; lipoids or plasmalogens providing they contain colamine
bound in the form of a phosphoric acid ester as base; sugars and
polysaccharide-like cell reserve substances and cell ingredients such as
hemi-celluloses, starches, pectins and lignins. Suitable compounds
containing H-acid groups also include: constituents of the cell walls of
bacteria such as polymers of amino sugars (acetyl flucosamine+N-acetyl
muramic acid) which are cross-linked by polypeptides in the N-acetyl
muramic acid component; cell wall constituents of fungi and algae such as
celluloses, hemi-celluloses; and other polysaccharides and chitin
fractions with acetyl glucosamine and acetyl galactosamine fractions.
The reactive organic fillers used in the polyisocyanate polyaddition
process of the invention are based on biomasses. The word "biomass" is
meant to include microorganisms and constituents or decomposition products
of microorganisms. Biomasses for the fillers may be denatured by reaction
with isocyanates and/or carbonyl compounds and compounds capable of
aminoplast and/or phenoplast formation. Processes for "working-up"
biomasses so as to be suitable for utilization in the plastics industry
are the subject of separate applications. In this context, "working-up" is
to be understood to mean that the biomasses are concentrated, irreversibly
denatured and deodorized so as to be suitable for utilization in the
plastics industry. Two of these methods suitable for producing fillers for
the process of the present invention are herein described in detail.
One of these processes for working-up a biomass comprises:
(a) condensing a biomass in a first reaction phase in aqueous medium with
carbonyl compounds, thiocarbonyl compounds and/or carbonyl compounds which
are in dissociation equilibrium with low molecular weight, uncondensed
N-alkylol compounds, optionally in the presence of a catalyst, optionally
in the presence of additives, and optionally with hydrolytic degradation
or denaturing of the cell walls present in the biomass;
(b) reacting in a second reaction phase the unreacted carbonyl compounds,
thiocarbonyl compounds and/or carbonyl compounds which are in equilibrium
with low molecular weight uncondensed N-alkylol compounds from the first
reaction phase, with aminoplast formers optionally containing N-alkylol
groups or with phenoplast formers, the second reaction phase being carried
out in aqueous medium optionally in the presence of a catalyst, optionally
in the presence of chain-terminators and optionally in the presence of
additives to produce a modified biomass; and
(c) optionally freeing the resulting modified biomass from undesirable
substances still present and/or optionally subjecting the resulting
modified biomass to an after-treatment.
Another process for working up a biomass comprises:
(a) reacting from 5 to 98% by weight, preferably from 20 to 97% by weight,
based on (a) and (b), of a biomass based on microorganisms and derivatives
or decomposition products thereof; with
(b) from 95 to 2% by weight, preferably from 80 to 3% by weight, based on
(a) and (b), of a compound containing isocyanate groups; optionally in the
presence of
(c) water and/or an organic solvent; and optionally in the presence of
(d) organic and/or inorganic additives; at temperatures of at least
50.degree. C., preferably from 50.degree. to 200.degree. C. and most
preferably from 80.degree. to 150.degree. C. The biomass is thus
substantially completely denatured.
The biomass polyaddition products worked-up by the two above-described
processes, are sterile, completely odorless in most cases, and denatured.
The products are not tacky in aqueous phase, may be filtered without
difficulty and dried in an energy-saving manner. They are completely
stable in storage and free from pathogenic organisms. The total enzyme
deactivation and complete cell death of cells in a biomass thus treated
results in complete suppression of decomposition and putrefaction
processes, fermentation, and unpleasant odor formation of enzymatically or
microbiologically degradable cell ingredients. Accordingly, the process
products may be stored indefinitely both in dry and also in moist form
without giving off unpleasant odors and without undergoing further
enzymatic degradation, and may readily be used at any time as fillers in
the production of polyurethane plastics.
Various generally known carbonyl compounds containing sufficiently reactive
carbonyl groups may be used for the denaturing process. Preferred carbonyl
compounds are aldehydes and ketones.
Particularly preferred aldehydes include saturated aliphatic, optionally
halogen- or hydroxy-substituted monoaldehydes such as formaldehyde,
acetaldehyde, butyraldehyde, isobutyraldehyde, pival aldehyde, chloral
hydroxy acetaldehyde, hydroxy pival aldehyde, glycerin aldehyde, hydroxy
aldehydes of the type present in formose-sugar mixtures and hydroxy
aldehydes formed from other aldehydes by aldol condensation reactions.
Other particularly preferred aldehydes include: unsaturated aliphatic
aldehydes such as acrolein and crotonaldehyde; cycloaliphatic aldehydes
such as cyclohexane aldehyde; aliphatic dialdehydes such as glyoxal,
methyl glyoxal, glyoxal sulfate and glutaric dialdehydes, aromatic
aldehydes such as benzaldehyde, 4-methyl benzaldehyde, salicyclic aldehyde
and terephthalic dialdehyde; and aldehydes derived from heterocyclic
compounds such as furfurol and hydroxy methyl furfurol.
It is also possible to use "masked aldehydes", i.e. compounds which either
release aldehydes or react like aldehydes under the reaction conditions.
Such masked aldehydes include: paraformaldehyde; trioxane; chloral
hydrate; hexamethylene tetramine; and semiacetals of aldehydes,
particularly formaldehyde, with monofunctional, difunctional or higher
polyfunctional alcohols such as methanol, ethanol, butanol, ethylene
glycol and diethylene glycol.
Particularly preferred ketones include hydroxy acetone, dihydroxy acetone,
methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, acetophenone,
and quinones such as benzoquinone.
It is also possible to use mixtures of aldehydes and/or ketones, mixtures
of formaldehyde with other aldehydes or ketones being particularly
preferred. Hydroxy aldehydes and hydroxy ketones may be formed in situ by
aldol condensation reactions from such mixtures of formaldehyde with
aldehydes or ketones containing hydrogen atoms in the .alpha.-position, as
illustrated in the following reaction scheme for formaldehyde and
isobutyraldehyde:
##STR1##
Ketones containing hydrogen atoms in the .alpha.-position may react
correspondingly with formaldehyde. Hydroxy aldehydes and polyhydroxy
ketones readily enter into addition reactions with, for example, urea and
numerous aminoplast formers, particularly in the mildly to strongly
alkaline range, to form N-alkylol compounds which in turn represent
condensation partners for biomasses.
Suitable thiocarbonyl compounds which may be used as reaction components
during the denaturing of the biomasses include various generally known
thiocarbonyl compounds containing sufficiently reactive thiocarbonyl
groups. Preferred thiocarbonyl compounds are thioaldehydes and
thioketones. Particularly preferred thioaldehydes and thioketones include
those derived from the aldehydes and ketones which have been mentioned
above as being particularly preferred.
It is also possible to use "masked thioaldehydes", i.e. compounds which
release thioaldehydes under the reaction conditions. Particular reference
is made to trimeric thioformaldehyde (trithian) which decomposes into
thioformaldehyde at elevated temperature in the presence of acids.
Carbonyl compounds which are in dissociation equilibrium with low molecular
weight uncondensed N-alkylol compounds include, preferably, simple
aldehydes, particularly formaldehyde, which are in equilibrium with the
corresponding N-methylol compounds. Such N-methylol compounds, preferably,
include N-methylol urea:
##STR2##
N,N'-dimethylol urea, methylolated dicyanodiamide, methylolated oxamide,
N-methylol thiourea, N,N'-dimethylol thiourea and methylolated melamines
such as hexamethylol melamine and tris-hydroxy methyl melamine
corresponding to the formula:
##STR3##
N-alkylol compounds suitable for the invention also include: monomethylol
ethylene urea corresponding to the formula:
##STR4##
monomethylol ethylene thiourea corresponding to the formula:
##STR5##
and tetramethylol acetylene diurea corresponding to the following formula:
##STR6##
It is also possible to use alkylol compounds of the type derived from
simple aldehydes, preferably those containing up to 5 carbon atoms.
The following are particularly preferred carbonyl compounds for carrying
out the process of the invention: formaldehyde; acetaldehyde;
isobutyraldehyde; crotonaldehyde; glyoxal; furfurol; hydroxy methyl
furfurol; salicyclic aldehyde and semi-acetals thereof; polymers of
formaldehyde such as paraformaldehyde and trioxane; hexamethylene
tetramine; and thioaldehydes such as thioformaldehyde. The uncondensed
(low molecular weight) N-alkylol compounds particularly preferred for
carrying out the process of the invention are N-methylol urea, dimethylol
urea, trimethylol melamine, hexamethylol melamine, monomethylene ethylene
urea, monomethylol ethylene thiourea and tetramethylol acetylene diurea.
As mentioned above, aminoplast formers may also be used in the process of
the invention for modifying the biomasses. In the context of the present
invention, aminoplast formers are to be understood to be nitrogen
compounds which are capable of forming N-oligocondensation and
N-polycondensation products with reactive carbonyl compounds.
Aminoplast formers which correspond to the above definition include
nitrogen compounds such as ureas, for example urea itself, acetylene urea,
dimethyl acetylene urea and N-methylene urea; thioureas such as
unsubstituted thiourea; and diureas such as hexamethylene diurea,
tetramethylene diurea and ethylene diurea. Aminoplast formers also include
polyureas of the type obtained by reacting aliphatic, cycloaliphatic or
araliphatic diisocyanates or triisocyanates or even biuret-polyisocyanates
with ammonia or primary amines; polycarboxylic acid amides such as oxalic
acid diamide, succinic acid diamide and adipic acid diamide; and
monourethanes, diurethanes and higher polyurethanes such as the reaction
products of aliphatic, cycloaliphatic, araliphatic and aromatic mono- or
bis-chloroformic acid esters with ammonia or primary amines. Suitable
aminoplast formers also include biurets; melamines such as melamine
itself; amidines such as dicyanodiamidine; guanidines such as
aminoguanidine; guanazoles; guanamines; cyanoamide; dicyanodiamide;
primary monoamines; secondary monoamines; aryl amines; ammonia; diamines;
triamines; hydrazines; carboxylic acid hydrazides such as
hydrazodicarbonamide; carbazinic acid esters and hydrazodicarboxylic acid
esters. Additionally, similar nitrogen compounds capable of aminoplast
formation can be used, preferably the derivatives containing N-alkylol
groups, preferably N-methylol groups, corresponding to the above-mentioned
nitrogen compounds and corresponding C.sub.1 -C.sub.4 alkyl ethers of
these N-alkylol derivatives.
Other preferred aminoplast formers include .alpha.,.omega.-diureas of
relatively high molecular weight, N-methylol derivatives thereof and
N-methylol alkyl ethers; .alpha.,.omega.-bis-alkoxy methyl urethanes
containing polyether, polythioether, polyacetal, polyester, polyester
amide or polycarbonate residues having an average molecular weight of from
400 to 10,000 and, optionally, additional urethane or substituted urea
groups between the functional groups in the .alpha.,.omega.-position.
Particularly preferred relatively high molecular weight nitrogen compounds
capable of aminoplast formation include compounds which may be dissolved
or dispersed in water such as compounds which, between the functional
urethane or urea groups in the .alpha.,.omega.-position, contain
polyethylene oxide residues or residues of copolymers of ethylene oxide
with propylene oxide, with tetrahydrofuran or with water-soluble
polyacetals produced from di-, tri- or tetraethylene glycol and
formaldehyde.
Aminoplast formers suitable for use as starting compounds in the process of
the invention are known or may be produced by known methods (cf.
Houben-Weyl "Methoden der Organischen Chemie", Volume XIV, Part 2, 1963,
pages 319-401, Georg Thieme-Verlag, Stuttgart).
"Modified aminoplast formers" may also be used as aminoplast formers for
denaturing the biomasses. Modified aminoplast formers are aminoplast
formers which contain additional groups readily capable of incorporation
into the polymer molecule. Examples of modified aminoplast formers are
compounds which may be rapidly and easily incorporated by mixed
condensation. Preferred modified aminoplast formers include polyurethanes
and polyureas containing terminal NH.sub.2 groups; polyamides of
poly-(.beta.-alanine) having molecular weights of up to 2000; N-methylol
methyl ethers of polycaprolactam; polythiolactams; polypeptides of
N-carboxy-.alpha.-aminocarboxylic acids; low molecular weight polyamides
of aliphatic dicarboxylic acids and diamines; polyamides of cycloaliphatic
components and aromatic components; polyamides containing oxygen, sulfur
or nitrogen as heteroatoms; polyester amides; mixed condensates which in
addition to amide groups also contain ester, urethane or urea groups;
ethoxylated and propoxylated monoamides and polyamides; polyhydrazides and
polyaminotriazoles; polysulfonamides; formaldehyde mixed condensates with
urea, melamine and dicyanodiamide; low molecular weight
aniline/formaldehyde condensates; sulfonic acid amides; mononitriles and
dinitriles; acrylonitrile; urotropin; hexahydrotriazines of primary amines
and formaldehyde; Schiff's bases and ketimines or polyketimines such as
those of 1 mol of hexamethylene diamine and 2 mols of cyclohexanone;
polyaddition products and polycondensation products of melamine and other
aminoheterocycles with aldehydes and alcohols; polyaddition and
polycondensation products of nitriles with aldehydes; and reaction
products of phosphorous acid and dialkyl phosphites with carbonyl
compounds and amines or polyamines. Other suitable compounds capable of
aminoplast formation include compounds described on pages 7 to 12 of
German Offenlegungsschrift No. 2,324,134.
Other modified aminoplast formers which may be used in the denaturing
process are N-alkylol compounds and, in particular, N-methylol compounds
(which may be partly etherified) with low molecular weight and relatively
high molecular weight polyfunctional hydroxyl compounds.
The following compounds in particular are suitable for use as aminoplast
formers for carrying out the denaturing process: urea; thiourea; diureas
such as hexamethylene diurea and tetramethylene diurea; ethylene urea;
acetylene urea; dimethyl acetylene urea; oxalic acid diamide; succinic
acid diamide; adipic acid diamide; mono- or bis-hydrazides such as
hydrazodicarbonamide; carbazinic acid methyl and ethyl ester;
hydrazodicarboxylic acid esters; monourethanes and, in particular,
diurethanes such as the reaction products of aliphatic, cycloaliphatic,
araliphatic and aromatic mono- or bis-chloroformic acid esters with
ammonia and primary amines; aniline; melamine; dicyanodiamide; cyanoamide;
aminoguanidine; dicyanodiamidine; guanamines; guanazoles; polyureas and
polybiurets of the type obtained by reacting aliphatic, cycloaliphatic,
araliphatic diisocyanates (or triisocyanates) and biuret polyisocyanates
with an excess of ammonia or primary amines.
Other aminoplast formers which may be used are generally known azulmic
acids, fault-containing so-called "modified acids", azulmic acids
stabilized by condensation with carbonyl compounds, azulmic acids
stabilized by condensation with carbonyl compounds and aminoplast formers
or low molecular weight condensation products thereof, and also metal salt
complexes of the above-mentioned azulmic acids. These compounds are
preferably used together with other aminoplast formers, particularly urea.
These various azulmic acids are known and are described in detail, for
example, in Houben-Weyl, "Methoden der Organischen Chemie" (1952), Volume
8, page 261; in Angewandte Chemie 72, (1960), pages 379-384; in German
Pat. Nos. 662,338 and 949,060; in German Offenlegungsschriften Nos.
2,806,019; and 2,806,020 (substantially corresponding to U.S.
applications, Ser. Nos. 11,542; and 11,554) and in U.S. application Ser.
No. 84,002 pending group 170.
Phenoplast formers suitable for use in the production of the denatured
biomasses used in the present invention include the known phenols and
derivatives thereof, such as phenol, cresol, bisphenol A, nitrophenol,
pyrocatechol, hydroquinone and naphthol sulfonic acid. Other aminoplast
and phenoplast monomers suitable for use as denaturing agents are
described in German Offenlegungsschriften Nos. 2,324,134; 2,713,198; and
2,728,523 and in U.S. Ser. No. 84,002 pending group 170.
Various condensation catalysts may be used for accelerating the denaturing
reaction of biomasses by means of carbonyl compounds and aminoplast or
phenoplast formers. Such condensation catalysts include acids such as
hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid,
phosphorous acid and other acids derived from phosphorous, formic acid,
acetic acid, thioacetic acid, maleic acid and oxalic acid. Suitable
catalysts for the denaturing reaction also include bases, such as sodium
hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, lead
hydroxide, zinc oxide, magnesium oxide and other metal oxides and hydrates
thereof. Additionally, salts may be used as catalysts, examples of which
include: phosphates such as primary or secondary potassium hydrogen
phosphate; ammonium sulfate; copper; zinc; tin(II); cadmium and magnesium
salts of various organic acids. Additionally, numerous organic acid
anhydrides and acid-yielding compounds such as ammonium chloride;
trimethyl ammonium formate; chloral hydrate; amine salts of formic acid
and other organic carboxylic acids; maleic acid semi-esters; tertiary
amine salts and tertiary amines; dibenzoyl peroxide; carbonic acid;
N-carbamic acids; glycol chlorohydrin; glycerol chlorohydrin and
epichlorohydrin may be used as catalysts.
Preferred catalysts are acids such as phosphoric acid, phosphorous acid,
nitric acid, hydrochloric acid, sulfuric acid, formic acid, oxalic acid
and maleic acid and bases such as sodium hydroxide, potassium hydroxide,
calcium hydroxide, barium hydroxide, lead hydroxide, benzyl dimethylamine
and triethylamine.
Where phosphoric acid or sulfuric acid is used as the condensation
catalyst, it may often be quantitatively deposited onto the products by
precipitation with calcium ions or, in the case of phosphoric acid, by
precipitation with iron or aluminum ions, so that the products do not have
to be washed out and the effluent is thereby saved from pollution.
Various monofunctional compounds suitable for chain-terminating reactions
may be used as chain-terminators in the denaturing process. It is
preferred to use monofunctional chain-terminators such as
.epsilon.-caprolactam, valerolactam, butyrolactam and the corresponding
thiolactams; formamide and actamide; alcohols such as methanol, ethanol,
propanol, butanol, allyl alcohol, isopropanol, oleyl alcohols and benzyl
alcohol, which stop the growing aminoplast segments by etherification
reactions. Other preferred chain-terminators include compounds of the type
described on pages 13 and 14 of German Offenlegungsschrift No. 2,324,134.
In one particular embodiment, N-methylol caprolactam, N-methylol
valerolactam, N-methylolbutyrolactam and N-methylol azalactams may also
function as chain-terminators. The last of these compounds have hitherto
been unknown. However, they may be produced from the corresponding
azalactams by methylolation with formaldehyde in known manner. The
azalactams which can be used are known (cf. German Offenlegungsschrift No.
2,035,800).
In the denaturing of the biomasses by means of carbonyl compounds and
aminoplast or phenoplast monomers, it may be advantageous to add
hydroxyalkane phosphonic acid esters or hydroxyalkane phosphonic acids,
particularly hydroxymethyl phosphonic acid ester or hydroxymethyl
phosphonic acid, because these substances enter into co-condensation
reactions with aminoplast formers via the hydroxymethyl group thereof and
at the same time are catalytically active.
It may also be advantageous to add from 10 to 20% by weight of mononitriles
and polynitriles such as acrylonitrile and, in particular,
hydroxyacetonitrile, to the biomasses before the condensation reactions
are carried out because hydroxyacetonitrile, for example, enters into
co-condensation reactions in the presence of formaldehyde and aminoplast
formers such as urea.
The described processes for denaturing biomasses are preferably carried out
in aqueous media or in aqueous alcohol media. At the same time, inert
organic solvents may be additionally used to remove the water
azeotropically on completion of the reaction. However, it is preferred to
use water without additional organic solvents as the reaction medium.
The reaction temperatures may be varied over a relatively wide range. In
general, the reaction is carried out at temperatures of from 0.degree. to
200.degree. C., preferably from 10.degree. to 150.degree. C. However, it
is also possible to complete the co-condensation reaction during the
drying process, for example during spray-drying at temperatures of up to
250.degree. C.
In many cases, the denaturing process may even be carried out
advantageously at room temperature. In this case, pathogenic germs
remaining may be killed by sterilization in the drying phase.
The denaturing reaction is generally carried out under normal pressure.
However, it is also possible to work under elevated or reduced pressure.
For example, the process may be carried out under elevated pressure at
temperatures of from 120.degree. to 160.degree. C., in which case not only
are the products sterilized, but also proteins, ribonucleic acid,
deoxyribonucleic acid, nucleoproteins and/or other cell ingredients are
also degraded as required.
In general, from about 0.1 to 6 mols, preferably from 0.2 to 5 mols, of
carbonyl compounds, thiocarbonyl compounds and/or low molecular weight,
uncondensed N-alkylol compounds in dissociation equilibrium with carbonyl
compounds and from 0.1 to 6 mols, preferably from 0.2 to 5 mols, of
aminoplast formers or phenoplast formers are added per kg of biomass
(having a solids content of from 1 to 16% by weight). Optional materials
including chain-terminators, catalysts and additives may be introduced in
such a quantity that they are present in the end product in a proportion
of from 1 to 95% by weight, preferably from 5 to 90% by weight.
Catalysts are generally used in quantities of from 0.05 to 10% by weight,
preferably from 0.1 to 5% by weight, based on that total quantity of all
the reaction components involved in the polycondensation reaction. In some
cases, however, much higher catalyst concentrations may be used. For
example, from 0.4 to 0.6 mol of acid catalyst, preferably phosphoric acid
or nitric acid, may be used per 100 g of biomass and azulmic acids when
the condensation reaction is carried out using azulmic acids. In this
case, products in which the catalyst acids are fixed to basic groups of
the co-condensates are formed.
Chain-terminators may be used in quantities of from 0.5 to 60% by weight,
based on the total quantity of the starting compounds capable of
aminoplast formation. Where N-methylol lactams or N-methylol azalactams
are used as chain-terminators, the concentrations thereof generally range
from 0.5 to 20% by weight, preferably from 2 to 14% by weight, based on
the total quantity of aminoplast formers and carbonyl compounds or
thiocarbonyl compounds.
Phenoplast formers may be used in quantities of from 0.5 to 100% by weight,
based on the biomasses.
In general, the denaturing process is carried out by adding carbonyl
compounds, thiocarbonyl compounds and/or carbonyl compounds in
dissociation equilibrium with low molecular weight, uncondensed N-alkylol
compounds, to an aqueous biomass dispersion optionally in the presence of
additives and/or a catalyst, and initiating | | |
