JP3155603B2 - Method for producing liquefied solution of lignocellulosic material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently liquefying a lignocellulosic substance such as wood to efficiently produce a wood liquefaction solution useful as a raw material for various resins having biodegradability or biodegradability. It is about. This lignocellulose liquefied solution is used for adhesives, molding materials, foams,
It is expected to be used as a resin material in a wide range of fields such as paints and filling materials.

[0002]

2. Description of the Related Art As a part of utilization of lignocellulosic substances containing wood, it has been proposed to liquefy the lignocellulose material to form a solution and use the resulting wood solution as a raw material for various resins. The means of liquefaction is roughly classified into a means for chemically modifying a lignocellulose substance such as wood and dissolving the chemically modified substance in an organic solvent, and a means for directly liquefying a lignocellulose substance such as wood without modification.

Various proposals have been made so far for liquefying lignocellulosic substances such as untreated wood without any chemical modification. For example, 200-260 in the presence of phenols or bisphenols
There has been proposed a method of heating at a high temperature of ° C. and under pressure (Japanese Patent Application Laid-Open No. 61-261358).

[0004] Similarly, lignocellulosic substances such as untreated wood are converted to polyhydric alcohols, oxyethers,
It has also been proposed that the compound can be liquefied and dissolved in cyclic ethers and ketones (JP-A-62-79230).

[0005] In addition, lignocellulosic substances such as wood,
Pre-treatment with halogen such as chlorination, then in a processing solution containing a liquefied dissolving agent such as a phenol compound, 200 ~
It has also been proposed that a liquefied solution of a lignocellulose substance can be efficiently and inexpensively produced by liquefaction and dissolution treatment at a high temperature of 260 ° C. (Japanese Patent Application Laid-Open No. 63-17961).
issue). Then, without chemically modifying these woods, phenols, polyhydric alcohols, polyethylene glycol, etc., in the presence of an acid catalyst, if necessary, at 100 to 300 ° C.
A technique for preparing an adhesive or a foam from a solution obtained by heating and liquefying and dissolving at the temperature described in Japanese Patent Application Laid-Open (JP-A) No. 1-45.
440, JP-A-1-158021, JP-A-1-15
No. 8022).

On the other hand, lignocellulosic substances such as wood flour and babas palm are liquefied at a temperature of about 100 to 200 ° C. while reacting with phenols in the presence of an acid catalyst, and neutralized by adding barium hydroxide. Thereafter, it is known that, by separating and removing free phenol by distillation under reduced pressure, a molding resin characterized by being three-dimensionally cured by heating in the presence of hexamethylenetetramine in the same manner as a novolak resin or the like is obtained ( JP-A-3-263417
Issue).

[0007]

In the conventional method, when a lignocellulose substance is liquefied and dissolved with a polyhydric alcohol having a small number of functional groups such as polyethylene glycol, a difference in liquefaction reaction behavior occurs due to a difference in tree species. The properties of the liquid material may differ. In addition, when liquefied and dissolved in a polyhydric alcohol having a small number of functional groups, the reactivity of the obtained liquefied product is low.For example, when a foam is made from this liquefied product, satisfactory foaming suitability is obtained and satisfactory physical properties are obtained Often not.

Thus, untreated wood is liquefied at 100 to 200 ° C. in the presence of an acid catalyst using polyhydric alcohols having three or more functional groups (aliphatic polyhydric alcohols, polyether polyols and polyester polyols). It has been practiced to dissolve and eliminate the influence of tree species such as wood and obtain useful and highly reactive resin raw materials. As a result, in many cases, a liquefied resin liquid having excellent foaming suitability has been obtained, and a foam having excellent physical properties has also been obtained. Among them, polycaprolactone polyol is characterized by itself being a biodegradable polymer or oligomer, has high liquefaction of lignocellulose, and is also found to be capable of easily leading to a foam having excellent physical properties. On the other hand, polycaprolactone polyol is very expensive as a polyol for polyurethane raw materials in terms of price, and the caprolactone oligomer has a drawback that its molecular weight is restricted when used.

[0009] The problem to be solved by the present invention is to solve these two problems, that is, using lignocellulose such as untreated wood by using a lower temperature at normal pressure and a lower catalyst addition amount. Liquefied and dissolved to provide a useful resin material having high reactivity.

[0010]

According to the present invention, a lignocellulosic substance such as wood or cellulose is prepared in the presence of an acid catalyst.
In the presence of a cyclic ester such as ε-caprolactone and a polyhydric alcohol such as glycerin, at a relatively low temperature of less than 100 to 200 ° C., by heating under normal pressure, lignocellulose or cellulose such as wood is subjected to alcoholysis, hydrolysis and the like. Low molecular weight, low molecular weight lignocellulose or cellulose component, ε
-Completed on the basis of the new fact that a solution can be obtained by liquefaction of lignocellulose or a cellulosic material which involves two or three reactions with cyclic esters such as caprolactone and polyhydric alcohols such as glycerin. It is.

The present invention has a feature that liquefaction can be promoted in the presence of a relatively small amount of an acid catalyst such as sulfuric acid such as 0.75% by weight based on the total amount of the cyclic ester and the polyhydric alcohol added to the reaction system. The reaction between the cyclic ester and the polyhydric alcohol, the polycondensation of the cyclic ester based on the reaction, the polymerization, and the reaction with the low molecular weight wood component of both components can occur depending on the reaction conditions in various ways, It is also possible to adjust the reactivity of the liquefied product to obtain a sufficiently high reactivity, and the viscosity of the liquefied product becomes variable,
It also has many potential uses and applications, such as obtaining good products by cross-linking reactions when making foams and the like.

[0012]

The lignocellulosic material or cellulose material used as a starting material in the present invention is wood flour, wood fiber, crushed wood such as wood chips or veneer chips, and plant fiber such as straw and fir. Various types of materials such as raw materials, GP (ground pulp), TMP (thermomechanical pulp), paper such as waste paper, and pulp are included, and any of those conventionally used in this type of field is used.

At this time, various types of wood are widely included, and representative examples include, for example, birch, sitka spruce, cedar, red pine, poplar, lauan and the like. The particle size of the pulverized product may be such that it can be sufficiently liquefied and dissolved.

The cyclic ester used in the present invention may be one which is polymerized by a redox reaction by a known method, for example, propiolactone, β-butyrolactone,
α, α'-bischloromethylpropiolactone, α, α
-Dimethyl-β-propiolactone, δ-valerolactone, β-ethyl-δ-valerolactone, 3,4,5-trimethoxy-δ-valerolactone, 1,4-dioxan-2-one, glycolide, trimethylcarbo , Neopentyl carbonate, ethylene oxalate, propylene oxalate, ε-caprolactone, α-methyl-ε-caprolactone, β-methyl-ε-caprolactone, γ-methyl-ε-caprolactone, 4-methyl-7
-Isopropyl-ε-caprolactone, 3,3,5-trimethyl-ε-caprolactone, cis-disalicylide,
Trisalicylide and the like. Among these cyclic esters, it is advantageous to use ε-caprolactone, which is easily available industrially, is easy to handle, and easily liquefies lignocellulose.

The polyhydric alcohols usable in the present invention include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-hexanediol, 2,4-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, pinacol, cyclopentane1,2-diol, Dihydric alcohols such as cyclohexane 1,4-diol, bisphenol A, polyoxypropylene glycol, polyoxypropylene-polyoxyethylene glycol and polyethylene glycol, glycerin, trimethylolpropane, triethanolamine, 1,2,6
Polyhydric alcohols having three or more functional groups such as hexanetriol, pentaerythritol, methylglucoside, sorbitol, mannitol, sucrose, and polyether polyols starting from these. Of these polyhydric alcohols,
It is advantageous to use glycerin, which is inexpensive, readily available industrially and sometimes used as a raw material for polycaprolactone.

In the liquefaction and dissolution, the above-mentioned cyclic ester and polyhydric alcohol are always used in combination, but one kind may be selected and used, or one or more kinds may be appropriately selected from each. More than one species can be used as a mixture.

Further, for the purpose of lowering the viscosity of the solution or promoting liquefaction and dissolution, water or monohydric alcohols, dihydric alcohols, polyhydric alcohols, acetone, One or more organic solvents such as ethyl acetate can be added and coexisted. At this time, examples of the monohydric alcohol include methyl alcohol, ethyl alcohol, n-butyl alcohol and the like, and examples of the dihydric or higher alcohol include those described above.

In the present invention, it is preferable to add a lignocellulosic substance such as wood at a ratio of 5 to 500 parts by weight based on 100 parts by weight of a mixed solution of a cyclic ester and a polyhydric alcohol. Although it is possible to obtain a liquefied product even if it is less than 5 parts by weight, it is not particularly suitable for the purpose of resinification. If too much is added, liquefaction tends to be insufficient.

The liquefaction and dissolution reaction referred to in the present invention means that a lignocellulose substance such as wood reacts with a mixed solution of a cyclic ester and a polyhydric alcohol and a reaction product of both.
Liquefaction of at least 75% from solid phase to liquid phase.

In the present invention, this reaction is carried out at normal pressure in the presence of an acid catalyst. The acid catalyst may be an inorganic acid, an organic acid, or a Lewis acid, such as sulfuric acid,
hydrochloric acid. Preferred examples include toluenesulfonic acid, phenolsulfonic acid, aluminum chloride, zinc chloride, and boron trifluoride. The amount to be used is usually 0.1 with respect to 100 parts by weight of the mixture of the cyclic ester and the polyhydric alcohol.
To 20 parts by weight, preferably 0.5 to 5 parts by weight.

The reaction temperature is from 100 to 200 ° C., preferably from 130 to 180 ° C., particularly preferably from 150 to 160 ° C. It is preferable to perform appropriate stirring during the liquefaction reaction. By this stirring, torque can be added to the suspension, and the efficiency of liquefaction and dissolution can be increased. Liquefaction dissolution is achieved in 15 minutes to several hours. The concentration of the lignocellulose substance such as wood in the liquefied product of the lignocellulose substance such as wood obtained in this way varies depending on the purpose of use of the solution,
The range is up to 90% by weight.

The device for dissolution may be any device that can carry out this reaction, and usually has an inner wall having high acid resistance and a reflux device, preferably a concentrator by vacuum distillation or the like. In the early stage of the reaction, if the whole reaction system material is well mixed, and in the later stage, a device capable of sufficient stirring or a device capable of performing such mixing and stirring efficiently throughout the reaction period, the liquefaction Promote dissolution,
This is desirable because the reaction conditions can be relaxed.

In the present invention, the lignocellulosic substance may be subjected to a pretreatment in advance and then subjected to the present reaction. By this pretreatment, liquefaction and dissolution can be achieved more easily. This pretreatment is described in JP-A-63-1796.
Any of the halogen pretreatments disclosed in No. 1 can be effectively applied.

[0024]

According to the present invention, a liquefied solution of a cyclic ester of a lignocellulosic substance such as untreated wood and the like with a polyhydric alcohol mixture, which has been considered impossible in the past, can be used.
It can be obtained by a reaction under normal pressure at a temperature of lower than 200 ° C. and preferably lower than 130 ° C. and 180 ° C. The reactions include alcoholicsis and hydrolysis of lignocellulose, as well as reactions of cyclic esters with polyhydric alcohols, reactions with low molecular weight lignocelluloses, polycondensation reactions of cyclic esters, and the like. Liquids are highly reactive,
In addition, characteristics such as the ability to control the reactivity under liquefaction conditions can be recognized.

Further, wood or the like is mixed with a mixed solution of a cyclic ester and a polyhydric alcohol in the presence of an acid catalyst to form a mixture of 100 to 200.
C. In particular, it is liquefied and dissolved only by heating at a relatively low temperature of 130 to 180 ° C. under normal pressure, and the liquefaction yield of wood is 98 on average.
The new fact that liquids can be obtained with yields as high as
It has been found for the first time by the present inventors. Sulfuric acid, for example, is used as the acid catalyst at that time, and its concentration is determined with respect to the mixed liquid amount of the cyclic ester and the polyhydric alcohol.
It has been found that even a low value such as 0.75% by weight or less can sufficiently achieve the purpose of liquefaction. The resulting liquid has high reactivity due to having many functional groups,
For example, when a foam is intended by urethane foaming, it is a "polyol" resin raw material particularly suitable for urethane foaming.

As described above, the method of the present invention can very easily obtain a liquefied solution, is suitable for industrialization, is extremely practical such as a polyol raw material for urethane foaming, and is an effective method for producing a lignocellulose raw material such as wood. Very useful for utilization.

[0027]

The present invention will be described in more detail with reference to the following examples.

[0028]

Example 1 Dry birch wood flour (20-80 mesh)
3 g of 0.75% by weight sulfuric acid (9
7% sulfuric acid) and 9 g of a mixed solution of glycerin and ε-caprolactone (mixing ratio, glycerin / ε-caprolactone = 1/3 (w / w)), together with a 50 ml glass reaction vessel equipped with a reflux condenser and a stirrer. The mixture was put into a flask, left standing in an oil bath at 150 ° C. for about 1 hour, and subsequently reacted by stirring for 1 hour. After the reaction was completed, the reaction solution was pulled up from the oil bath, immediately added with an equal amount of barium hydroxide octahydrate to the sulfuric acid added, and neutralized to terminate the reaction. The reaction product was poured into excess dioxane and diluted to determine the extent of solubilization.

Next, glass fiber filter paper (TOYO GA-
100; retention of 1 μm diameter particles), the diluted reaction solution was filtered to separate a liquefied product and an insoluble residue. The insoluble residue was further washed several times with 1,4-dioxane, preliminarily dried, dried at 105 ° C. for 4 hours, and weighed to determine the insoluble residue ratio. The obtained insoluble residue ratio was 13.1%. The OH value of the liquefied product was 236.2 (KOH mg / g), as shown in the lower part of Table 5 below.

[0030]

Example 2-10 In Example 1, the conditions were as shown in Table 1.
Glycerin / ε-caprolactone [1/3 (w / w)) in which a sulfuric acid catalyst [0.75% by weight / (glycerin + ε-caprolactone)] is uniformly mixed with 3 g of dried birch wood flour. ] The mixed liquid amount is 3,
In addition to 6, 12, 15, 18, 21, 24, 30, and 36 g, liquefaction and dissolution were performed under the same conditions as those of Example 1. Table 1 shows the results.

[0031]

[Table 1]

[0032]

Examples 11 to 30 In Example 1, the conditions were as shown in Table 2, that is, a sulfuric acid catalyst [0.75% by weight / (glycerin + ε-
Glycerin / ε- uniformly mixed with caprolactone)]
When adding 9 or 12 g of the mixed solution of caprolactone, the addition ratio of glycerin and ε-caprolactone was set to 0 in the latter addition ratio [ε-caprolactone addition ratio (%)].
-100%, and the other conditions were the same as in Example 1.
Liquefaction and dissolution were performed under the same conditions as described above. Table 2 shows the results. It is known that there is a glycerin / ε-caprolactone mixture ratio that minimizes the residue ratio, and the ratio is around 1/3.

[0033]

[Table 2]

[0034]

Examples 31 to 37 In Example 1, liquefaction and dissolution were performed under the predetermined conditions shown in Table 3, that is, the conditions where only the reaction time was changed. Table 3 shows the results. 1
It can be seen that the residue ratio is minimized by the reaction for 50 minutes. If a longer liquefaction time was taken, a reaction between the liquefied components occurred, and the residue ratio increased rather.

[0035]

[Table 3]

[0036]

Examples 38 to 42 In Example 1, liquefaction and dissolution were performed under the predetermined conditions shown in Table 4, that is, conditions in which only the reaction temperature was changed. Table 4 shows the results.

[0037]

[Table 4]

Considering also the results of Example 1, 150
Residue at 13.1%, 160 ° C and 180
It can be seen that the residue ratio was further reduced at ℃. However, when liquefied at 160 ° C. and 180 ° C., the residue was reduced, but severely clogged during filtration. This means that a high molecular weight component is present in the solubilized product. It is considered that caprolactone was polymerized and polymerized. This takes sulfuric acid and glycerin and ε-caprolactone in the same proportions here,
When the reaction is carried out without wood flour (160 or 180 ° C., 2 hours), the reaction solution is significantly colored and a part of the solution becomes gel-like and dissolves in dioxane as compared with the reaction at a lower temperature, but is filtered. In comparison with the IR spectrum of the residue, there was no change in the absorption of the asymmetric trisubstituted benzene at 815 cm ^-1 indicating the presence of lignin. 1720cm
^This is supported by the increased absorption of C = D, which is considered to be derived from the ester bond of the homo- ¹ and graft polymer (polycaprolactone) ^-1 . Therefore,
If a higher temperature than the conditions here is used, the polymerization of caprolactone during the liquefaction (it is thought to be accompanied by the reaction with glycerin and degraded wood components in the meantime) proceeds, and the apparent residue rate further increases Will increase.

[0039]

Embodiment 43-51 In Embodiment 1, the conditions are shown in Table 5, ie, the catalyst addition amount (catalyst concentration).
Liquefaction and dissolution were performed as the only condition changed. Table 5 shows the results.

[0040]

[Table 5]

As shown in Table 5, the amount of the insoluble residue rapidly decreases and increases again when a small amount of the sulfuric acid catalyst is added. That is, it is understood that there is an appropriate value for the amount of the catalyst added. This is because if the additive amount of the catalyst is too large, the reaction proceeds too much,
It is considered to cause recondensation of low molecular weight wood components such as lignin.

Further, in the portion up to the vicinity of the appropriate catalyst value in Table 5, the measurement results of the hydroxyl value (OH value) of the reaction product, that is, the liquefied solution as a whole are also shown. It is known that the OH value clearly decreases with the decrease in the amount of the insoluble residue, and that the amount of the hydroxyl group decreases due to the reaction as the liquefaction proceeds. This result also indicates that the liquefaction of the present invention involves a reaction between the components.

Continued on the front page (72) Inventor Jin Tsugaya 1239 Shinzaizai, Aboshi-ku, Himeji-shi Daicel Chemical Industry Co., Ltd. (72) Inventor Kinichi Shirakawa 4-1-1186 Okai, Fukushima-ku, Osaka-shi, Osaka Rengo (56) References JP-A-2-227434 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 3/11

Claims (2)

(57) [Claims] 1. A method for producing a liquefied solution of a lignocellulose material, comprising heating the lignocellulose material in the presence of an acid catalyst, a cyclic ester and a polyhydric alcohol. 2. The method according to claim 1, wherein the heating temperature is in the range of 100 to 200 ° C., and the acid catalyst is at least one selected from inorganic acids, organic acids and Lewis acids.