DE10057910C2 - Process for the derivatization of technical lignin, derivatized technical lignin and its use - Google Patents

Description

The invention relates to a method for the derivatization of techni Schem lignin, the derivatized lignin and its use.

By lignin is meant a plant component, in addition to the cellulose second most common in plants. The proportion of lignin in the wood can ever amount to 20 to 40%. In other plants is a part of the lignin matrix replaced by silicate structures (for example in straw).

Lignin consists, chemically speaking, of a three-dimensional network of three various phenylpropane units: cumaryl, coniferyl and sinapinal alcohol.  

As a rule, lignin accumulates in the production of pulp, whereby it Normalerwei se burned for energy. This is problematic insofar as when The conventional pulp extraction process sulfur and Chlorverbindun be partially used in the combustion of Ablau which contains the lignin, become free and pollute the environment. Common Ver driving here are the sulfate, force, soda or sulfite method (L. Göttsching and C. Katz, Papier-Lexikon, Deutscher Betriebswirte-Verlag GmbH, 1999).

Because native lignin due to the size of the macromolecule and its crosslinked Structure is almost insoluble in all solvents, it must during the Digestion process are dismantled. The above-mentioned conventional Ver drive to use this a digestion system, the water as a basis has. Depending on the type for the digestion sulfur compounds or for the subsequent bleaching step chlorine compounds, for example chlorine dioxide, turned puts.

Recent developments use organic solvents for the digestion of Biomass. For example, the Organosolv process uses a system of Al water and water (Jaakko Pöyry, Environmentally friendly pulping Agricultural Publishing 1997). For the natural product described in WO 96/335013 Pulping process, formic acid is added with the addition of hydrogen peroxide puts. Natural Pulping AG has further developed this procedure in the meantime cels and suggests solvent mixtures, the carboxylic acids or carboxylic acid derivatives and another, essentially aprotic, organic solvent include use. This advanced process is in a German Patent application of the company Natural Pulping AG described the same priority as the present application has.

Other methods that except water still using organic Lö are Alcell (alcohol), Milox (formic acid, peroxide), ASAM (alcohol), acetocell (acetic) and formacell (acetic acid, Formic acid). A description of the pulping process, the organic Lö use environmentally friendly technologies for the pulp and paper industry "by A. Young and M. Akhtar, John Wiley & Sons, 1998.  

In 1998, according to PPI, International Fact & Price, 2000, worldwide fell approximately 142 million tons of pulp. Simplified, it can be assumed that per ge a ton of pulp is obtained about half a ton of lignin. So were In 1996 in the USA 52,862,000 tons of pulp corresponding to approx. 26 million tons Lignin or in Canada 13,379,000 tons of pulp corresponding to about 7 million tons lignin is produced.

In addition to the main combustion of lignin was vorla lignin as feed, fertilizer, drilling mud and cement additive or To use flavoring.

In "Lignin Derivatives III Sulfonate Esters" by Kaliprasanna Dhara, Rajesh K. Jain and Wolfgang G. Glasser was attached to Holzforschung 47 (1993) 403-411 showed that lignosulfonate also used as an anionic industrial surfactant can be. Also, this article teaches that, albeit with limited success, the lignosulfonates are used in polymeric materials, plastic and resin can.

Depending on the particular pulping process lignin falls, possibly also Lignin derivatives, such as lignosulfonate, and partly relatively volatile Degradation products of lignin, such as. B. cumaryl, coniferyl and Sinapinalkohol whose Derivatives such as the syringa or guaiacyl aldehyde, syringol, guaiacol, short-chain Condensation products such as esters, ethers or hemiacetals and degradation products of lignocellulosic material, such as sugar or their breakdown products, in different proportions. This mixture of lignin and degradation product which are recovered from the waste liquor of the corresponding process can, hereinafter referred to as technical lignin or lignin for short.

The nature and the respective proportions of the lignin and the degradation products is dependent on the type and the reaction in the respective digestion process. Conditions which promote the formation of degradation products are high temperatures, high acidity, oxidizing agents (for example H ₂ O ₂ , O ₂ , O ₃ peracids), long digestion times and chemical additives.

The degradation of lignin and also of the whole lignocellulosic material during the digestion process is characterized by a high acidity of the solvent  so that, in particular, in the conventional natural pulp Process which is carried out in formic acid as a solvent for the formation short-chain lignin degradation products and low molecular weight compounds comes. In less acidic long-chain carboxylic acids, the technical lignin less short-chain lignin degradation products and low molecular weight compounds.

However, in the other digestion processes, the organic Lö in addition to the macromolecular lignin lignin degradation products, Coumaryl, coniferyl and sinapinal alcohols, their derivatives, short chain condensates onsprodukte and low molecular weight compounds.

In addition, the lignin with double bonds, carbonyl, carboxy is the digestion groups, derivatives such as vanillin, syringaldehyde, syringol, vanillic acid, syringasäu 4-hydroxybenzoic acid, aceto-vanillin, acetosyringone and dihydroconiferylal produced kohol.

The "lignin" obtained in the sulfite process is essentially lignosulfonate.

Since the technical lignin obtained in pulp production also degradation products of lignin and lignocellulosic material, difficulties arise during use or further processing. Thus it was found that in the Further processing of the technique obtained by the natural pulping method rule lignin as a polymer compound, z. B. in injection molding or extrusion and the necessary heating, which is necessary for the conversion of the mixture into the flowable condition is required, volatiles escape, which can lead to erhebli odor, possibly even a health impairment lead.

Also lead low boiling components of lignin or degradation products of the lignocellulosic material when extruded into webs and ridges the later shaped body, which is of course undesirable.

The melting range of natural pulping lignin was about 160 to 165 ° C determined, the glass transition temperature is 60 ° C.  

The invention is based on the object, a refining process for techni beautiful lignin and refined technical lignin and new high quality ge applications found for the refined lignin.

The object is achieved by the features of claim 1 and 15, 16, 19 and 20 ge solves.

By the implementation of the technical lignin with the at least monofunktio nelle spacer according to feature a) or the at least bifunctional spacer GE According to feature b), the spacer is added to the degradation products and volatiles tied the technical lignin and thereby a boiling point increase he enough, so that both the odor nuisance and health hazards as well the formation of floating, also caused by low-boiling constituents Skinning and burrs in polymer production is avoided.

By the reaction with the at least monofunctional spacer (a) becomes the you depunkt of the converted decomposition product increased, so that when sufficient mol mass even at the required temperature increase in polymer production no more volatiles escape.

That according to the known and the newly developed Natural Pulping method won technical lignin was analyzed and - as in the join the results of the experiments - it has been found that natural pulping Lignin is comparatively short-chained. Furthermore, it was found that it the odor-intensive volatile compound responsible for the odor nuisance should be responsible for heating the lignin, probably around Furfu rylaldehyd, which results from the acid digestion of biomass. It is considered assured that the furfurylaldehyde, which formed as a degradation product of cellulose is separated due to its solubility behavior together with the lignin and gets into the lignin fraction.

The boiling range of the coniferyl alcohol is 163 to 165 ° C, the boiling points the other lignin fragments are in a similar range. furfuryl boils at 162 ° C.

If furfuraldehyde according to the invention already with a relatively short-chain alipha table spacer, for example n-butanol, molecular weight 74 g / mol, reacted  2-furfuryl-aldehyde-di (n-butyl) -acetal, which already has a boiling point of 244- 245 ° C has. It was found that by reacting with a monofunctional spacer obtained products from a molecular weight of the spacer of at least 70 g / mol, preferably at least 90 g / mol, sufficiently high Have boiling points, so that even with temperature increase to 190 ° C to 200 ° C almost no volatile components escape.

Is the monofunctional spacer out of the aromatic compounds selects, then a phenyl radical is already sufficient to the desired increase of To reach boiling point.

In the reaction with a bifunctional spacer, the binding of the one takes place functional group of the spacer in general to a degradation product and the second functional group reacts directly or possibly after chain formation with others Spacer molecules with another degradation product or with macromolecular Lignin, so that by increasing the molecular weight, the boiling points of the bound Volatile compounds increase and thus the leakage of volatile substances parts is also avoided when heated.

The spacer has at least one or at least two nucleophilic groups. Nucleophilic groups are understood below to mean those groups which a to an electropositive central atom, usually carbon, bound electro more negative heteroatom, the nucleophile. In the case of organometallic Compounds is referred to by central atom the respective metal.

In many cases, the electrophile, that is, the positive central atom, intervenes the nucleophile bears, for example on an aliphatic or aromatic Hy droxygruppe a component of the technical lignin to form the entspre ether or ester and cleavage of the nucleophilic leaving group. This reaction is believed to be due to nucleophilic substitution rests.

Also, the addition of the spacer to double bonds, the individual verbin tions of technical lignin. The addition is preferably in the acidic Medium instead, so that probably first an electrophilic attack takes place.  

As there are a variety of different components of technical lignin and one Variety of different reaction possibilities exist, in addition to nucleophilic ones Substitution reactions and additions to double bonds a number of others Reactions and reaction mechanisms.

If a spacer with at least two functional groups is used, then the Molar mass of at least bifunctional spacer also below 70 g / mol, because the bifunctional spacer binds with the one functional group to a first Component of the technical lignin, in particular a fragment or degradation product and with the second functional group to another fragment or degradation product or to another spacer molecule or a Ligninmakromole kül, so that the boiling point by increasing the mass of bound Ab building product rises.

The chain formation of the at least bifunctional spacer molecules with each other is quite desirable because with a flexible longer chain the probability binding to other fragments or degradation products or even to macromolecules lares lignin is increased. The chain formation of the spacer molecules with each other can by addition of the spacer molecules in excess, d. H. at least 1 to 100, as well by suitable reaction conditions, in particular temperature increase, he be raised.

Below are some of the reactions that are involved in the implementation of the Degradation products containing technical lignin with a monofunctional, a bifunctional and a trifunctional spacer expire. The reactions are cumene alcohol, sinapine alcohol or its derivatives and furfuraldehyde shown. However, the reaction is - albeit to a much lesser extent - also between two or more lignin macromolecules or between ei a degradation product of lignin or lignocellulosic material and ma cromolecular lignin.

Depending on whether the mono- or bifunctional spacer a (Di) hydroxy group or its derivatives or a (di) carboxy group or de In general, as a product, the corresponding products (Di) ester or (di) ether. Upon addition of the nucleophilic spacer to a  Double bond can, depending on the type of spacer used also other Verbin be obtained.

The representation of the reaction possibilities, which is certainly not complete, should serve the better understanding of the invention, but the invention is not be limit. It is essential in the present invention that the erfindungsge according to derivatized technical lignin has good properties and no volatile Contains more ingredients so that it used for polymer processing who that can. On which reaction mechanisms, which reaction sequences etc. the Implementation is irrelevant to the execution of the invention.

In the implementation of carboxylic acids and their derivatives with furfuraldehyde he follows Knoevenagel reaction to form the α-, β-unsaturated carboxylic acid derivatives derivatives. In the implementation of Furfurylaldehyden with alcohols, alkyl halides and reactive cyclic ethers, such as oxirane derivatives, the Formation of semiacetals and acetals and, where appropriate, of polyethers.

Among others also occur - especially in acidic medium - the following also listed side reactions.  

A) Reactions on conversion of the lignin degradation products using the example of the coniferyl alcohol with a monofunctional spacer XR ²

1. esterification or etherification on the monofunctional hydroxy group

R ¹ = arbitrary
Etherification with R ² = alkyl or aryl radical
Esterification with

with R * = alkyl or aryl radical

2. Etherification by addition to a double bond

R ¹ = arbitrary
Etherification with R ² = alkyl or aryl radical

B) Reactions on conversion of the lignin degradation products using the example of the coniferyl alcohol with a bifunctional spacer

1. Addition of the bifunctional spacer to two double bonds

R ¹ = any 2
Formation of the diether with R ² = alkyl or aryl radical

2. Addition of the bifunctional spacer to a double bond, condensation of further bifunctional spacer, addition to a second double bond of a Ligninabbauproduktes

R ¹ = any 2
Formation of the diether with R ² = alkyl or aryl radical

3. esterification or etherification of the phenolic hydroxyl groups

R ¹ = arbitrary
Diether formation with R ² = alkyl or aryl radical
Diester formation with

with R * = alkyl or aryl radical

4. esterification or etherification of the phenolic hydroxyl groups with condensation of the spacer

R ¹ = arbitrary
Diether formation with R ² = alkyl or aryl radical
Diester formation with

with R * = alkyl or aryl radical

C) Reaction upon reaction of the lignin degradation products with a trifunctional spacer on the example of maleic acid

or

D) Reaction of the spacer with furfuraldehyde (bifunctional)

Possible reactions of propylene oxide with furfuraldehyde

E) side reactions in the acid

1. Umetherung

2. Addition of two coniferyl alcohols

F) Possible follow-up reactions

(Production of wood pulp from beech wood according to the Formacell method. Dissertation. Hamburg 1998)

1. Polar reaction

a) α-aryl ether cleavage

b) β-aryl ether cleavage

2. Homopolar β-aryl ether cleavage

3. Solvolytic β-aryl ether cleavage

4. General fragmentation reaction

5. Inhibition by formylation

A reaction of the spacer can in principle ent with all in the technical lignin individual compounds, for example coumaryl alcohol, coniferyl alcohol, Si napin alcohol, derivatives thereof, furfuraldehyde, but also on the macromolecule lignin itself. Due to the number of available reaction centers, d. H. in general, hydroxy groups, double bonds and the aldehyde function, the number of degradation products present and their reaction centers in the Ver equal to the macromolecular lignin and steric conditions is ever but the probability of the attack of the spacer ge a degradation product increased over the attack on the macromolecular lignin.

With a suitable choice of the reaction conditions and selection of the spacer can ever but also the macromolecular lignin by reaction with the spacer modifi and thus obtained macromolecular lignin with altered properties become.

The nucleophilic group of the spacer preferably comprises one or more Ele from the group of halogens, chalcogens such as oxygen or sulfur or pnicogens such as nitrogen, phosphorus, arsenic or antimony.

In principle, nucleophilic groups are all known nucleophilic groups For example, hydroxy, halide, in particular chloride, bromide, iodide, Pseudohalide groups such as cyano, isocyanato, isothio and thiocyanato, cya nato, amino, alkoxy, aryloxy and mercapto groups, formyl, oxo groups and analogous compounds such as imino groups and their derivatives such as acetals, car boxygruppen or their derivatives such as halocarbonyl, pseudohalogencarbonyl, Carbonyloxycarbonyl, aminocarbonyl, alkoxy and aryloxycarbonyl, ketenes, Nitrogen derivatives of carboxylic acids such as amidocarbonyl and hydrazinocar bonylgruppen.

Suitable organic spacers with a functional group are, for example, the following compounds having a molecular weight of at least 70 g / mol, preferably of at least 90 g / mol:
Alkyl or aryl alcohols such as, for example, decanol, phenol, benzyl alcohol, polyols, polyethylene glycol, poly- / tri- / tetra- / pentamethyl alcohol and the corresponding halo genides and pseudohalides of these compounds, the carboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, Caproic acid, lauric acid, Ben zoesäure, stearic acid, fatty acids in general, lauric acid, caproic acid chloride, and their derivatives such as acid halides, amides, esters, anhydrides and ketenes.

Also unsaturated compounds which additionally comprise a nucleophilic group, can be used. Examples are vinylacetic acid, vinyl chloride, allyl alcohol, Methacrylic acid, oleic acid, cinnamic acid, alloximic acid, styrenesulfonic acid, isocroton acid, linoleic acid, linolenic acid, acrylic acid, crotonic acid and sorbic acid.

After addition or substitution of the spacer to a component of the technical lignin, the double bond (s) may then z. B. radically be networked. Likewise, nucleophilic polymerization is possible.

The spacer having two functional groups may comprise both two identical and two different functional groups. Examples of bifunctional spacers are:
Dihydroxy compounds and their derivatives such as glycol, polyethylene glycol, propylene oxide, ethylene oxide, butylene oxide, epichlorohydrin, dihalogen compounds, alkylhydroxyhalides, halocarboxylic acids and their derivatives, dicarboxylic acids and their derivatives such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, phthalic acids including the iso- and of terephthalic acid, pimelic acid, suberic acid, azelaic acid, sabacic acid and their (di) acid halides, (di) esters, (di) amides, (di) carboxylates, (di) ketenes, (di) hydrazides, including mixed carboxylic acid derivatives, and anhydrides.

At least bifunctional spacers may also be unsaturated compounds, such as unsaturated dicarboxylic acids and their derivatives are used, for example Maleic acid, fumaric acid. The double bonds can in a further step For example, be crosslinked radically or nucleophilic.  

The spacers with two nucleophilic groups and one double bond already show three reaction centers. The two nucleophilic groups allow the linea re networking, the double bond allows for a later radical or nucleophilic spatial networking.

It is also possible to include spacers with three functional nucleophilic groups put. Examples are trihydroxy compounds, trihalogen compounds or also mixed hydroxycarboxyl compounds such as tartaric acid, citric acid, halogen dicarboxylic acids. Similarly, carbonic acid derivatives such as phosgene or urea be used. Taking into account the steric conditions can with These trifunctional spacers a spatial crosslinking of the lignin fragments take place among each other, d. H. refined lignin with essentially duroplasti properties are obtained.

To connect the degradation products, the lignin and the attached to these spacers ßend three-dimensional network, for example, radically, the spacer can also we have at least one double or triple bond.

It is also possible, as a spacer an organometallic compound such as a Grignard connection z. B. Alkylmagnesiumhalogenid, an alkylzinc compound or an aromatic organometallic compound such as phenyl or benzylmagnesi umhalogenide, for example, the aldehyde and keto functions can add up.

Also inorganic compounds can be used as spacers. Examples are silicon compounds such as siloxanes, silicones, alkyl or aryltrihalosilanes or mixtures thereof, dialkylhalosilanes, but also phosphoric acid derivatives, Nitrogen oxides, halogen-sulfur, halogen-selenium and boron compounds.

The choice of the solvent for the implementation of the spacer with the technical Lignin hangs u. a. from the spacer used.  

The etherification of the technical lignin can be carried out both in alkaline aqueous solu tion, as well as in other basic solution media, such as in Wil liamson's ether synthesis. The esterification is both acid catalyzed in the aqueous Me medium (preferably with H ₂ SO ₄ or H ₃ PO ₄ ), as well as ba cally catalyzed with aqueous Na ₂ CO ₃ - or NaHCO ₃ or dilute Alka lilösung possible. Also, the esterification in organic solvents such as pyridine or an inert solvent such as toluene, optionally with the use of additives such as dimethylaminopyridine, take place.

A preferred embodiment of the present invention provides the Vernet tion of technical lignin by etherification with dihydroxy compounds or To achieve epoxides.

Another preferred embodiment provides the networking of the technical Lignins by esterification before.

The refined obtained essentially by etherification or esterification technical lignin is generally characterized by water insolubility, UV Resistance, higher glass transition point and thermoset property out.

In the specific case of polyethylene glycol etherified technical lignin a modified lignin with low glass transition temperature and thermoplastic properties which is due to the flexibility of the polyether chain (Plasticizer function).

On the choice of the spacer in the process for the derivatization of technical lignin, the properties of the derivatized lignin beispielswei to those desired for the use of the derivatized lignin in polymers Properties are adapted. Thus, the biodegradability of the derivatized lignin by the introduction of nitrogen-containing spacers ver improve. Also, the rheological properties of the later polymer can be and change tensile strength and elastic modulus. Short-chain lignin ester cause a decrease in the viscosity of the melt of CAB (cellulose acetate / butyrate). Lignin butyl esters can be used to increase crosslinking in polyurethanes become.  

The technical lignin derivatized by the reaction with the spacer can be described as Polymer compound used in the production of polymers and on Tempe temperatures above the softening point, for example for injection molding or Ex trudieren, warmed, without it to the unwanted release übelrie harmful and harmful components such as Furfurylaldehyde comes. This is explained by the Meßer discussed in the experiments proven results.

The further processing of the derivatized technical lignin can, for example together with another polymer in known devices for Injection molding or extrusion, which are intended for the production of moldings, respectively.

The derivatized lignin and a second polymer (before molding in the processing machine) by mixing. The processor has so the ability to create a recipe that suits the exact requirements profile of his product.

If the derivatized technical lignin is replaced by the use of spacers with double or triple bonds still having unsaturated functions, may after addition a thermally unstable radical starter to the refined lignin the Vernet tion reaction can be initiated in the extruder. In the case of injection molding is the Heated tool and thus initiated the networking process.

The inventively derivatized lignin, in particular derivatized according to the invention Lignin, which is based on the well-known or further developed Natural Pulping Method or a method using at least one organi is prepared in the solvent, can be used in the Polymerver be used as an addition to conventional polymers to their  Improve properties, e.g. B. the elasticity of the polymer, tensile strength, Ela Stizitätsmodul etc. increase. Also, the derivatized lignin itself can be cheaper thermosetting plastic can be used. After natural pulping Method or a method using at least one organi technical carboxylic acid obtained in the solvent technical lignin is in Ge Substitute to many conventional lignins free of sulfur and chlorine compounds gene.

With the inventively derivatized lignin is also a cost-effective and environmentally friendly polymer additive available because fall as a "waste product" annually at least 60 million tons (!) of technical lignin worldwide the derivatization process according to the invention, for example for the production of plastics can be used, resulting in a cost-effective, environmental friendly and resource-saving production of polymers possible.

The inventively derivatized lignin, in particular the natural pulping lignin or the lignin obtained by digestion in a carboxylic acid containing Lö can be obtained, for example, together with polyhydroxy butter acid are used. The resulting lignin / polyhydroxybutyric acid blends characterized by biodegradability and improved rheological and Strength properties. Depending on the desired application derivati lignin as a compound to enhance the brittleness of PHB, thus a Generate product with completely new properties or it can be a formula provided that are stiff and tough as polypropylene or soft or flexi bel is like polyethylene.

Also, the inventively derivatized lignin is suitable as a filler. This gewin In addition to their volume-increasing, cost-effective effect also for the Verar fertility and the properties of the material (for example, biological Ab Buildability) increasingly important.

The derivatized lignin can also be used as an additive to other polymers cellulose acetate / butyrate CAB, polyurethane, poly- Ethylene vinyl acetate and polystyrene.  

The invention will be described below with reference to embodiments and Meßergeb described in more detail.

Experimental part A. Preparation of lignin

In the experiments carried out as lignin according to the known and lignin obtained from the further developed natural pulping process. The Digestion conditions for the conventional natural pulping method, which in the WO 96/335013 was as follows: 90% by weight of formic acid, 10% by weight Water, raw material: wheat straw (dry content = 96%), cooking time two Hours, refluxing (105 ° C); Peroxide content 1% based on the dry substance; Fleet ratio: 1: 4.

The digestion conditions for the advanced natural pulp Lignin produced in a German patent application of the company Natural Pulping AG with the same priority date as the present application be were as follows: 13% formic acid, 75% acetic acid, 2% cyclo hexanone, temperature T = 170 ° C, cooking time two hours, raw material: spruce schnitzel, liquor ratio 1: 4.

B. embodiments of the implementation of the technical lignin with different spacers 1. Etherification of technical lignin 1.1 Experimental procedure

In a three-neck round bottom flask with stirrer and thermometer, opening device for taking a pH meter sample in a water bath, 10.0 g of natural pulp Lignin presented and mixed with 30.0 ml of sodium hydroxide solution as a solvent. The pH of the reaction mixture should be 11-12 at this time.  

Propylene oxide is added with a dropping funnel over a half hour period. The second batch of propylene oxide is added after four hours and the third Charge after another eight to twelve hours. The pH is between 10.5 and 12.5 and the temperature kept at 30 ° C, the pH and the Temperature constantly controlled. The reaction mixture is still eight Stirred at 30 ° C for hours.

To react the remaining propylene oxide, the reaction is heated final mixture for half an hour at 45 ° C. The reaction mixture is precipitated with 60.0 ml of hydrochloric acid, the pH should be 2 after precipitation. The liquid is decanted, the residue gewwe three times with water until neutral and then dried over phosphorus pentoxide in vacuo.

1.2 Scope

Etherified lignin can be used in polymer processing during injection molding become. By the binding of the low-molecular substances are volatile Odorants, which in the warming of the lignin and its derivatives on it required injection molding temperature of about 200 ° C can escape, no longer before handen.

2. Esterification of the technical lignin 2.1 Experimental procedure

10.0 g of lignin are in 200 ml of solvent, which is listed in the table below, in a three-necked flask (with stirrer, thermometer, reflux condenser) before. Via a dropping funnel, 50.0 g of the relevant spacer are added within one hour with stirring at room temperature. The reaction mixture is kept at room temperature for two hours and stirred. It is then heated to 50 ° C for one hour. The temperature is constantly monitored. At the end of the reaction, the mixture is poured into a beaker with 500 ml of ice-water, which was acidified with 50.0 ml of concentrated hydrochloric acid. The reacted lignin is filtered off with suction through a frit, washed neutral with water and dried over phosphorus pentoxide in vacuo.

2.2 Scope

The scope is 1.2.

3. Reaction with dichlorodimethylsilane 3.1 Experimental procedure

10.0 g of lignin are dissolved in 200 ml of dichloromethane and 30.0 g of pyridine in a three-necked flask (with KPG-Rüher, dropping funnel, reflux condenser) submitted. 44.0 g of dichlorodimethylsi lan are mixed with 100 ml of dichloromethane and a drip funnel inside 0.5 h with stirring at room temperature. The reaction mixture is 3 h kept at room temperature and stirred. Then it will be on for 1 h  Heated to 50 ° C. The product is evaporated on a vacuum evaporator at 40 ° C. to Finally, it is washed with 200 ml of 1% hydrochloric acid and finally with water washed neutral. The product is dried in a desiccator.

3.2 Scope

The scope of application of the products is 1.2.

4. Implementation with phosgene 4.1 Experimental procedure

5.0 g of lignin are dissolved in 200 ml of toluene and 30.3 g of triethylamine in a 1 liter three-necked flask (with magnetic stirrer, cooled fine dosing funnel, reflux condenser with phosphorus pentoxide drying tube and thermometer) submitted. Then 42.0 g will be 20 % phosgene solution (in toluene) in the dropping funnel and within 0.5 hours added with stirring at room temperature. The reaction mixture is kept at room temperature for six hours and stirred. Then who The 100 ml of 10% NaOH slowly added dropwise with ice cooling. The product will worked up and dried over phosphorus pentoxide.

4.2 Scope

The scope of application of the product is 1.2.

C. Analytics

As far as in the following investigation of Natural pulping lignin is mentioned, it is that by the conventional method (WO 96/335013) ago Asked lignin (see A).  

1. IR spectroscopy 1.1 Comparison of the spectra

To the dependence of the obtained technical lignin of the kind of inserted Raw material to check, were first straw and spruce wood as lignocellulosic materials according to the known and weiterentwic celt natural-pulping process open-minded and the obtained technical Lignins from straw and spruce wood analyzed by IR spectroscopy.

All obtained IR spectra of natural pulping lignins from straw and spruce wood show good agreement with the Björkmann lignin spectra of the spectra Catalog Hummel; Scholl, Carl Hanser Verlag. This literature spectrum was on native lignin extracted from spruce wood meal, ie without chemical loading action, measured.

Of the available comparison spectra, that of the Björkmann lignin spectrum (untreated spruce lignin) similar to the recorded spectrum (Literature: K. V. Sarkanen, C. H. Ludwig: Lignins: Occurence, Formation, Structure and Reactions, Wiley-Intersience New York 1971, pages 166 ff.).

The IR spectra from Natural Pulping Spruce Lignin and Natural Pulping Strohlignin are shown below as FIG .

The spectra have the typical lignin bands at 1463 cm ^-1 for the asymmetric CH deformation, 1511 cm ^-1 and 1513 cm ^-1 and 1602 cm ^-1 for the aromati cal ring vibration with high intensity and width, and 1718th cm ^-1 and 1719 cm ^-1 for carbonyl groups unconjugated to the aromatic ring and 3410 cm ^-1 and 3421 cm ^-1 for the hydroxy groups.

Furthermore, in spruce lignin, only the guaiacyl band occurs at 1270 (typical of Soft wood lignin) and, in the case of straw lignin, with low intensity, the syringa Band 1325 on.

The spruce lignin is also a broad and intense band between 1000 and 1100 to recognize what evidence of the presence of sugar and Polysaccha rid shares. This also confirms the Zuc keranalyse.  

1.2 result

The IR spectra of the spruce wood and the straw birch show little deviation tions, that is, the nature of the raw material used is slightly on the nature and composition of the technical lignin obtained effect.

The agreement with the literary spectrum of lignin further proves that the degradation products contained in the Natural-Pulping Technical Lignin have largely the same functional groups as the native lignin, and it does not become a major chemical by the natural pulping process Change in the lignins, as it is the case, for example, when carrying out the sulfite Process in which lignosulfonate is formed comes.

2. Elemental analysis of prepared by various methods lignins

The elemental analysis revealed

In the natural pulping method, oxygen is introduced into the molecule due to the solvent (aromatic hydroxilation by O ₂ or H ₂ O ₂ ). The oxygen content increases, the carbon content decreases. Ether is cleaved in acidic medium into two hydroxyl groups. This is partly due to the shorter Ket th in natural pulping lignin.

The analyzed nitrogen content of Natural Pulping Lignin will be Proteins (from Straw). According to Lindner, "Systematic characterization of Lignins from digestions according to the Organocell method ", Dissertation TU Mün Chen (1989), results with% protein = 6.25 ×% nitrogen, that one of a Share of 12.5% of proteins can go out.

The nitrogen contents of the other lignins are negligibly small.

3. Analysis results of headspace GC / MS examinations

• a) Headspace GC / MS studies were performed to analyze the volatile odor-intensive and harmful substances of technical lignin. The technical lignin obtained by the natural pulping method is shown in Fig. 2a. The evaluation of the chromatogram and the mass spectra of the natural natural pulping lignin gave a peak at around 650, indicating the presence of furfuraldehyde.
  The furfuraldehyde is expected to be formed in the digestion of cellulose by degradation of sugars, especially xylose, is not soluble in water and is precipitated together with the lignin. This substance is very odor-intensive and responsible for the odor nuisance in the warming of lignin.
• b) After crosslinking of the low molecular weight fractions in the lignin with adipic acid dichloride (compare B 2.1.6), headspace GC / MS analyzes were also carried out, the gas chromatogram of the lignin adipic acid ester is shown in FIG . The chromatogram indicates the implementation of the spacer, since the peak of furfuraldehyde is missing at about 650.
  The recorded spectra still show solvent bands, which suggests inadequate drying. The investigations show that the complete conversion / crosslinking of the low-molecular-weight furfuraldehyde originating from the degradation of the cellulose as well as the other degradation products has taken place.

4. Sugar analysis

The type of sugar contained in the Natural-Pulping spruce lignin was be and it was found that about 20% of this sugar is gluco about 72% are xylose and about 8% galactose. The same sugar Distribution also includes straw-made natural pulping lignin. The Proportion of total sugars in the respective lignin is strongly affected by the Type and repetition of the washing process dependent.

Organocell lignin contains, according to Lindner et al., "Systematic Characteristics tion of lignins from digestions using the Organocell method ", dissertation TU Munich (1989), additionally mannose.

5. Molar mass distribution

The molecular weight distribution determined for natural-pulping lignin is shown in FIG. 3. The measurement was carried out on sulfonated polystyrene with THF by gel permeation chromatography (GPC). The molecular weight distribution of Natural Pulping Lignin, recorded by GPC and calibrated with sulfonated polystyrenes of sizes 1100, 4480, 6200, 15200 and 29500 and vanillin (M _m = 152), shows a very broad distribution curve. It starts with small proportions in the high molecular weight range at about 10,000 g / mol. Peak maxima were found at molecular weights of 4000 g / mol and 1200 g / mol, the average distribution is 3500 g / mol. It can be seen from the curve that low molecular weight fractions are also present.

6. ¹³ C, ¹ H NMR

¹ H-NMR

¹³ C-NMR

Frequency (ppm) assignment 170 COOH groups 129/135 Aromatic C 77 CDCL ₃ (solvent) 56 OMe groups 29 CH ₂ groups (acetylated) 21 CH ₂ groups 30/22/14 methyl groups 0 TMS

Claims (6)

1. A process for the derivatization of technical lignin, characterized by reacting technical lignin with a spacer, either

• a) at least one functional nucleophilic group and a molecular weight of at least 70 g / mol, preferably at least 90 g / mol

or

• a) at least two functional nucleophilic groups.

2. The method according to claim 1, characterized in that the nucleophilic Group of Spacer Epoxides, carboxylic acid chlorides, dichloroalkylsilanes and Phosgene. 3. The method according to claim 1 to 2, characterized in that the technical lignin is reacted with the spacer in alkaline solution. 4. The method according to claim 1 to 2, characterized in that the technical lignin is reacted with the spacer in acidic solution.   5. Derivatized technical lignin obtainable by the process according to one of claims 1 to 4. 6. Use of the derivatized technical lignin according to claim 5 as Polymer, as a filler or additive in polymer production.