JP2019173237A - Method for producing aromatic monomer - Google Patents

Abstract

To provide a simple production method of obtaining an aromatic monomer such as vanillin, a vanillic acid, syringaldehyde, a syringic acid, acetovanillon and acetosyringone, which can be used as raw materials of a perfume, a phenol resin, an epoxy resin, a dispersion agent and an adhesive with using wood as a raw material, with high yield.SOLUTION: A method includes a step of cooking wood with soda includes adding 0.001 to 10 mass% of a quinone compound per wood absolute dry weight, adding oxygen after start of cooking, and then adding air to cook the wood with soda to produce an aromatic monomer.SELECTED DRAWING: None

Description

  This invention manufactures an aromatic monomer from the lignin decomposition product in the black liquor discharged | emitted from the process of digesting wood with soda.

In recent years, it has been studied to decompose lignin as an alternative to petroleum to produce an aromatic monomer as a raw material for phenol resin and epoxy resin. Lignin is present in a large amount in wood, but in order to extract it, chemical treatment using acid, alkali, or organic solvent, mechanical treatment such as pulverization is necessary. For example, in the sulfite cooking method, a mixed solution of acidic sulfite and sulfite is added and steamed at 130 to 145 ° C. to elute lignin in the wood as lignin sulfonate (for example, Patent Document 1). Add chemicals mainly composed of caustic soda (NaOH) and sodium sulfide (Na ₂ S), digest at about 150 to 160 ° C. and elute as kraft lignin. However, since lignin obtained by these methods is chemically modified and contains sulfur element in the molecule, it is not preferable for resin applications. Therefore, it has been studied to elute lignin by adding an alkaline aqueous solution such as caustic soda (Patent Document 2).

  It is also important to efficiently separate the extracted lignin. For example, it is disclosed that black liquor obtained by a kraft cooking method or the like is acidified to precipitate lignin and dehydrate, and the lignin filter cake is washed to obtain lignin (Patent Document 3).

JP 2001-89986 A JP 2014-208803 A Special table 2008-513549 gazette

  However, the lignin obtained by the above method has a high molecular weight, and it is necessary to perform a further decomposition treatment in order to obtain an aromatic monomer.

  An object of the present invention is to obtain an aromatic monomer from wood by a simple production method with a high yield.

The inventors of the present invention have made extensive studies in order to solve the above-mentioned problems, and in the step of soda cooking of wood, oxygen is added after the start of cooking, and then soda cooking is performed by adding air until the end of cooking. Thus, it was found that an aromatic monomer can be produced efficiently. The main configuration of the present invention is as follows.
(1) In the step of cooking wood with soda, adding 0.001 to 10% by mass of the quinone compound per absolute dry weight of wood, adding oxygen after the start of cooking, and then adding air and then soda cooking A method for producing an aromatic monomer.
(2) The method for producing an aromatic monomer according to (1), wherein oxygen is added for 10 to 240 minutes from the start of cooking and then air is added until the end of cooking.
(3) The method for producing an aromatic monomer according to (1) or (2), wherein the soda digestion is performed at a liquid ratio of 5.0 or more.

  According to the present invention, it is possible to efficiently produce an aromatic monomer using wood as a raw material. At the same time, low molecular weight lignin and pulp can be produced.

  The present invention includes a step of adding 0.001 to 10% by mass of a quinone compound per absolute dry weight of wood in the step of cooking wood with soda, and adding oxygen and then adding air and then soda cooking. This is a method for producing a monomer. The present invention will be specifically described below.

Either hardwood or coniferous wood can be used as the wood for the soda cooking process . Specifically, the broad-leaved trees include beech, China, birch, poplar, eucalyptus, acacia, oak, itaya maple, senoki, elm, giraffe, honoki, willow, sen, basamushi, konara, kunugi, tochinoki, zelkova, mizume, mizuzuki Aodamo etc. are exemplified. As conifers, cedar, spruce, larch, black pine, todomatsu, himekomatsu, yew, neko, spruce, iramimi, fir, sawara, togasawara, asunaro, hiba, tsuga, kotsutsuga, hinoki, yew, yellowtail, spruce (Beihiba), Lawson Hinoki (Beihi), Douglas fir (Bay pine), Sitka spruce (Beisuhi), Radiata pine, Eastern spruce, Eastern white pine, Western larch, Western fur, Western hemlock, Tamarack and the like.

  The wood is put into the digester along with the cooking liquor and used for soda cooking. Also, there are no particular limitations on cooking types such as 1 vessel liquid phase type, 1 vessel gas phase / liquid phase type, 2 vessel liquid phase / gas phase type, and 2 vessel liquid phase type. That is, the step of impregnating and holding the alkaline aqueous solution of the present application may be installed separately from the conventional apparatus or part for the permeation treatment of the cooking liquid. Preferably, the unbleached pulp that has been cooked is washed with a washing device such as a diffusion washer after extracting the cooking liquor. The form of the wood is not particularly limited, such as a chip or a powder.

  The soda cooking process can be performed by putting wood chips in a pressure resistant container together with soda cooking liquid, but the shape and size of the container are not particularly limited. The liquid ratio of the wood chip to the cooking liquid (chemical solution volume / wood chip solid content weight) can be 1.0 L / kg or more and 40 L / kg or less, preferably 1.5 L / kg or more and 35 L / kg. More preferably, it is 0 L / kg or more and 30 L / kg or less. When the liquid ratio is less than 1.0 L / kg, lignin is not sufficiently decomposed, and the yield of the obtained aromatic monomer is lowered. Moreover, even if the liquid ratio exceeds 40 L / kg, the improvement in the yield of the aromatic monomer obtained reaches its peak.

  In the soda cooking of the present invention, it is necessary to add oxygen after the start of cooking. The oxygen may be added by a method in which oxygen is blown into a flow-type digester and pressurized, and the oxygen pressure is preferably 0.01 to 1 MPa. Oxygen is preferably added for 10 to 240 minutes after the start of cooking, and more preferably 20 to 180 minutes. Oxygen may be added in portions, or may be added in portions as appropriate so that the oxygen pressure does not decrease during cooking.

  Furthermore, in the present invention, it is essential to add air until the end of cooking after adding oxygen. The air pressure is preferably 0.01 to 1 MPa. By adding air after adding oxygen, an aromatic monomer can be efficiently produced, and at the same time, a pulp can be produced in high yield.

  Moreover, in the soda cooking of this invention, it is necessary to add 0.001-10 mass% of quinone compounds with respect to an absolutely dry wood, It is preferable to add 0.01-7 mass%. When the addition amount of the quinone compound is less than 0.001% by mass, the yield of the aromatic monomer obtained in the black liquor is not sufficient. Moreover, even if the addition amount of a quinone compound exceeds 10 mass%, the further improvement of the yield of an aromatic monomer is not recognized.

  The quinone compound used is a quinone compound, hydroquinone compound or precursor thereof as a so-called known cooking aid, and at least one compound selected from these can be used. Examples of these compounds include anthraquinone, dihydroanthraquinone (for example, 1,4-dihydroanthraquinone), tetrahydroanthraquinone (for example, 1,4,4a, 9a-tetrahydroanthraquinone, 1,2,3,4-tetrahydroanthraquinone). Methyl anthraquinone (eg 1-methyl anthraquinone, 2-methyl anthraquinone), methyl dihydroanthraquinone (eg 2-methyl-1,4-dihydroanthraquinone), methyl tetrahydroanthraquinone (eg 1-methyl-1,4,4a) , 9a-tetrahydroanthraquinone, 2-methyl-1,4,4a, 9a-tetrahydroanthraquinone) and the like, anthrahydroquinone (generally 9,10-dihydroxyanthracene), Tyranthrahydroquinone (for example, 2-methylanthrahydroquinone), dihydroanthrahydroanthraquinone (for example, 1,4-dihydro-9,10-dihydroxyanthracene) or an alkali metal salt thereof (for example, disodium salt of anthrahydroquinone, 1 , 4-dihydro-9,10-dihydroxyanthracene disodium salt), and precursors such as anthrone, anthranol, methylanthrone, and methylanthranol. These precursors have the potential to convert to quinone compounds or hydroquinone compounds under cooking conditions.

  It is preferable that a soda cooking liquid sets the addition rate of sodium hydroxide per wood dry weight to 15-200 mass%. When the addition rate of sodium hydroxide is less than 15% by mass, the decomposition of lignin is insufficient and the yield of the aromatic monomer is lowered. .

  It is preferable to perform soda cooking in the temperature range of 140-180 degreeC, and 150-170 degreeC is more preferable. If the temperature is too low, elution of the lignin degradation product into the black liquor is insufficient, and if the temperature is too high, the eluted lignin is excessively decomposed, making it difficult to recover in the subsequent step. The cooking time in the present invention is the time from when the cooking temperature reaches the maximum temperature until the temperature starts to drop, and the cooking time is preferably 60 minutes to 600 minutes, preferably 120 minutes to 360 minutes. Is more preferable. If the cooking time is less than 60 minutes, the lignin degradation product is not sufficiently eluted, and the amount of lignin to be eluted reaches a peak even if it exceeds 600 minutes.

  In the soda cooking in the present invention, the processing temperature and processing time can be set using the H factor (Hf) as an index. The H factor is a standard representing the total amount of heat given to the reaction system in the cooking process, and is represented by the following equation. The H factor is calculated by time integration from the time when chips and water are mixed until the end of cooking. In the present invention, the H factor is preferably 250 to 2500. If the H factor is less than 250, the yield of the aromatic monomer is lowered, and if it exceeds 2500, the yield of the aromatic monomer reaches a peak.

Hf = ∫exp (43.20-16113 / T) dt
[Wherein T represents an absolute temperature at a certain point]
The obtained black liquor contains an aromatic monomer, and for example, vanillin, vanillic acid, syringaldehyde, syringic acid, acetovanillone, and acetosyringone are obtained.

  In the present invention, the unbleached (unbleached) pulp obtained after cooking can be subjected to various treatments as necessary. For example, bleaching can be performed on unbleached pulp obtained after cooking. Moreover, the obtained pulp can be used for papermaking, and it is also possible to produce saccharides using this as a raw material.

  The aromatic monomer produced in the black liquor according to the present invention can be separated and purified by a known method such as precipitation, extraction, distillation, recrystallization, adsorbent and the like.

  Examples of the distillation include vacuum distillation, distillation under a protective gas atmosphere, or steam distillation.

  Aromatic monomers can be separated and purified by extraction. In order to separate the aromatic monomer formed in the black liquor, an organic solvent is added to the black liquor and mixed (liquid-liquid extraction). Examples of the organic solvent include water-immiscible organic solvents, for example, hydrocarbons having 5 to 12 carbon atoms such as hexane or octane, chlorinated hydrocarbons having 1 to 10 carbon atoms such as dichloromethane or chloroform, and diethyl ether. Alternatively, aliphatic ethers having 2 to 10 carbon atoms such as diisopropyl ether, cyclic ethers, aliphatic esters such as ethyl ethanolate, and the like can be given. Or in order to isolate | separate an aromatic monomer, the method of adding and mixing the carbon dioxide of a supercritical state besides an organic solvent is mentioned.

  In addition, the aromatic monomer in the black liquor can be separated and purified from the black liquor by treatment with a basic adsorbent, particularly an anion exchanger. Aromatic monomers adsorbed on the anion exchanger can be liberated by treatment with an acid, preferably a dilute solution of mineral acid or organic acid in an organic solvent or aqueous organic solvent mixture.

  Since the black liquor contains dissolved lignin degradation products in addition to the aromatic monomer, for example, the lignin degradation products can be separated by the following method. In the present invention, the obtained lignin degradation product has a molecular weight of about 800 to 2500, and can be used as a thermosetting resin, a dispersant, and an adhesive. Further, it can be used as a phenol resin raw material or an epoxy resin raw material by further reducing the molecular weight.

Step of adding acid and / or carbon dioxide to black liquor and precipitating lignin decomposition product Acid and / or carbon dioxide is added to black liquor obtained after soda cooking, and the pH of black liquor is preferably 1 to 9, preferably By adjusting to 2-8, it becomes possible to precipitate the lignin decomposition product dissolved in the black liquor. This step may be repeated twice or more. When pH 9 is exceeded, precipitates of lignin decomposition products are not sufficiently generated, and when the pH is less than 1, the lignin decomposition products are decomposed and the recovery rate of the precipitates is lowered. The acid used may be an inorganic acid or an organic acid. Examples of the inorganic acid include sulfuric acid, sulfurous acid, hydrochloric acid, nitric acid, nitrous acid, phosphoric acid, and carbonic acid, and sulfuric acid is preferable. Moreover, you may use the residual acid discharged | emitted from a chlorine dioxide generator. Examples of the organic acid include acetic acid, lactic acid, succinic acid, citric acid, formic acid and the like. The black liquor can be concentrated using an evaporator or the like before adjusting the pH, and the solid content is preferably 10% by mass or more, more preferably 20% by mass or more and 50% by mass or less. .

  The temperature for adjusting the pH of the black liquor to 1 to 9 is preferably room temperature to 100 ° C. If the temperature exceeds 100 ° C., lignin condenses, and the molecular weight of the lignin degradation product increases.

  Further, prior to the step of adjusting the pH to 1 to 9, it is preferable to provide a step of adjusting the pH to 7 to 9 by adding carbon dioxide. Although it does not specifically limit as processing temperature, About 80 degreeC is preferable. Although the method of adding carbon dioxide is not particularly limited, there is a method of blowing under atmospheric pressure, or a method of blowing carbon dioxide in a sealed container and pressurizing (0.1 to 1 MPa). As carbon dioxide, pure carbon dioxide gas may be used, but it is also possible to use a gas containing carbon dioxide generated from a combustion exhaust gas discharged from an incinerator, a boiler, or the like, or a lime firing process.

  Further, if necessary, a flocculant may be added to promote precipitation of the lignin degradation product. Examples of the aggregating agent include sulfuric acid band, aluminum chloride, polyaluminum chloride, polyamine, DADMAC, melamic acid colloid, ginangiazide and the like.

The step of dehydrating and washing the produced precipitate and separating the precipitate The precipitate of the lignin decomposition product obtained in the step of adjusting the pH to 1 to 9 by adding acid and / or carbon dioxide is dehydrated with water Wash. As an apparatus for dehydrating and washing the precipitate, a filter press, a drum press, a centrifugal dehydration apparatus, a suction filtration apparatus, and the like can be used. The pH of water used for washing is preferably 1 to 9, and the temperature is preferably room temperature to 80 ° C.

  Further, even after the step of adjusting the pH to 1 to 9 by adding carbon dioxide, the precipitate is similarly dehydrated and washed.

  The aromatic monomer obtained by this invention can be utilized as a raw material of a fragrance | flavor, a phenol resin, an epoxy resin, a dispersing agent, and an adhesive agent.

  EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In addition,% in an Example and a comparative example shows the mass% unless there is particular notice.

[Example 1]
A 10-liter flow-through autoclave is charged with 300 g of cedar chip dry weight, 90% sodium hydroxide (vs. chip dry weight), tetrahydroanthraquinone (1,4-dihydro-9,10-dihydroxyanthracene disodium, Kawasaki) Kasei Kogyo Co., Ltd., trade name: SAQ) is 0.02% (vs. dry weight with respect to chips), and the cooking chemical is added so that the liquid ratio is 15. The cooking temperature is 170 ° C. for 4 hours, H factor = 4000. Soda and AQ cooking were performed to obtain pulp and black liquor. At this time, oxygen was added so that the oxygen pressure was 0.1 MPa (oxygen addition amount: 5 L / min, 2% per minute (chip dry weight)) for 80 minutes after the start of cooking, and then the air pressure was 0.1 MPa (air addition) Air was added to the end of cooking so that the amount was 5 L / min, 2% per minute (chip dry weight).

[Comparative Example 1]
A 10-liter flow-through autoclave is charged with 300 g of cedar chip dry weight, 90% sodium hydroxide (vs. chip dry weight), tetrahydroanthraquinone (1,4-dihydro-9,10-dihydroxyanthracene disodium, Kawasaki) Kasei Kogyo Co., Ltd., trade name: SAQ) is 0.02% (vs. dry weight with respect to chips), and the cooking chemical is added so that the liquid ratio is 15. The cooking temperature is 170 ° C. for 4 hours, H factor = 4000. Soda and AQ cooking were performed to obtain pulp and black liquor. At this time, oxygen was added so that the oxygen pressure was 0.1 MPa (oxygen addition amount 5 L / min, 2% per minute (chip dry weight)) from the start to the end of cooking.

[Comparative Example 2]
A 10-liter flow-through autoclave is charged with 300 g of cedar chip dry weight, 90% sodium hydroxide (vs. chip dry weight), tetrahydroanthraquinone (1,4-dihydro-9,10-dihydroxyanthracene disodium, Kawasaki) Kasei Kogyo Co., Ltd., trade name: SAQ) is 0.02% (vs. dry weight with respect to chips), and the cooking chemical is added so that the liquid ratio is 15. The cooking temperature is 170 ° C. for 4 hours, H factor = 4000. Soda and AQ cooking were performed to obtain pulp and black liquor. At this time, air was added from the start to the end of the cooking so that the air pressure was 0.1 MPa (air addition amount 5 L / min, 2% per minute (chip dry weight)).

[Comparative Example 3]
A 10-liter flow-through autoclave is charged with 300 g of cedar chip dry weight, 90% sodium hydroxide (vs. chip dry weight), tetrahydroanthraquinone (1,4-dihydro-9,10-dihydroxyanthracene disodium, Kawasaki) Kasei Kogyo Co., Ltd., trade name: SAQ) is 0.02% (vs. dry weight with respect to chips), and the cooking chemical is added so that the liquid ratio is 15. The cooking temperature is 170 ° C. for 4 hours, H factor = 4000. Soda and AQ cooking were performed to obtain pulp and black liquor. At this time, air is added so that the air pressure is 0.1 MPa (air addition amount 5 L / min, 2% per minute (chip dry weight)) for 80 minutes after the start of cooking, and then the oxygen pressure is 0.1 MPa (oxygen addition) Oxygen was added until the end of cooking so that the amount was 5 L / min and 2% per minute (chip dry weight).

  The yield of the aromatic monomer in the black liquor obtained in Examples and Comparative Examples was measured by the following method. Moreover, the total yield of the pulp, the selective yield, and the dredging rate were measured by the following methods. The results are shown in Table 1.

<Measurement of aromatic monomer>
・ Analyzer: High-performance liquid chromatograph LcSolution Multi-PDA
-Column used: Shim-pack VP-ODS 150mm (length) x 4.6mm (diameter)
・ Eluent: 0.1% formic acid: acetonitrile = 9: 1 mixed solution ・ Flow rate: 0.1% formic acid is 0.9 ml / min, acetonitrile is 0.1 ml / min
・ Detection: UV detector (280nm)
Standard solutions of various concentrations were prepared using standard products (vanillin, vanillic acid, 4-hydroxybenzaldehyde, acetoguaiacon), and a calibration curve was prepared from the peak areas and concentrations obtained by measurement under the above conditions. Next, the black liquor appropriately diluted with the eluent was measured under the above conditions. The peak area corresponding to the obtained vanillin, vanillic acid, 4-hydroxybenzaldehyde, and acetoguaiacon and the concentration obtained from the calibration curve were defined as the aromatic monomer concentration in the black liquor. Aromatic monomer yield was calculated from aromatic monomer concentration and liquid ratio during cooking.

<Total yield>
It was calculated from the absolute dry weight of wood chips before cooking and the absolute dry weight of unbleached pulp obtained after cooking.

<Measurement of selection yield and cocoon rate>
The finely selected pulp yield and cocoon rate were calculated from the weight of the pulp that passed through the 8-cut flat screen (A) and the weight of the pulp that did not pass (B) by the following equation.
Selection yield = 100 × A / (A + B)
粕 rate = 100 × B / (A + B)

  As shown in Table 1, according to the method according to the example, the aromatic monomer can be produced in a high yield, and the obtained pulp has few wrinkles and a high selection yield.

Claims (3)

  In the step of cooking soda with wood, a fragrance comprising a step of adding 0.001 to 10% by mass of a quinone compound per absolute dry weight of wood, adding oxygen after the start of cooking, and then adding air and then cooking soda A method for producing a group monomer.   The method for producing an aromatic monomer according to claim 1, wherein oxygen is added for 10 to 240 minutes from the start of cooking and then air is added until the end of cooking.   The method for producing an aromatic monomer according to claim 1 or 2, wherein soda cooking is performed at a liquid ratio of 5.0 or more.