JPS5912670B2 - Method for producing S-triazine compounds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing S-triazine compounds, and in particular to a method for producing S-triazine compounds by reacting cyanuric chloride, phenols, and diphenols. .

The present inventors discovered that a specific S-triazine compound containing a halogen has excellent properties as a flame retardant for synthetic resins, etc., and filed a patent application for this (Japanese Patent Application No.
-157300: see Japanese Unexamined Patent Publication No. 52-90193).

This compound has two S-triazine rings obtained by reacting cyanuric chloride with phenols and diphenols.
These are oligomer type 1 compounds having the above, and by using halogen compounds as phenols and/or diphenols, compounds effective as flame retardants for synthetic resins etc. can be obtained. However, since an organic solvent such as tetrahydrofuran (THF) was used as a reaction solvent at the beginning of the development of the S-triazine compound, it was difficult to recover the solvent.

That is, when an alkali is added during the reaction, water is added to the solvent, and when the solvent is recovered, the water and the solvent azeotropically boil, making it impossible to separate the two by distillation. Furthermore, when separating and purifying the product, the same organic solvent as in the water-containing reaction system is sometimes used, and recovery of this solvent also poses a problem. The present inventor conducted various studies and studies to improve the method for producing S-triazine compounds, and came up with the idea of carrying out the reaction in an organic solvent uniformly containing water. By using this method,
It becomes possible to reuse the azeotrope of water and organic solvent obtained by distillation as a reaction solvent as is. However, it has been found that S-triazine compounds produced using water-containing organic solvents are more unstable and more susceptible to thermal decomposition than those obtained using only organic solvents. This S-triazine compound is used as a flame retardant for synthetic resins, etc., and those that are prone to thermal decomposition are undesirable because they cause discoloration and performance deterioration of the synthetic resins. Therefore, when the cause of this instability was investigated, it was found that the cause was that cyanuric chloride reacted with water in the solvent and the number of OH groups bonded to the S-triazine ring increased. Therefore,
Further research revealed that the reaction between cyanuric chloride and water was suppressed by lowering the reaction temperature, and that the reaction at low temperatures was sufficient up to the point at which alkali addition began.

Of course, it is also possible to carry out the reaction at a low temperature after addition of the alkali, but this is not a satisfactory production method because the reaction rate decreases and the production takes a long time. That is, the present invention provides cyanuric chloride, and a mol of a phenol (3-2a) represented by the following (1) and a mol of a diphenol represented by the following () per 1 mol of cyanuric chloride (provided that O≦a<1 ) is treated with 3 equivalents or more of alkali to produce the S-triazine compound represented by () below, in which the solvent used is an organic solvent uniformly containing water, and cyanuric chloride is This is a method for producing an S-triazine compound, which is characterized in that the temperature of the reaction solution is maintained at 5° C. or lower from the time it is dissolved in a solvent until the start of an alkali treatment. In the method of the present invention, the solvent can be easily recovered, and the water-containing solvent obtained by distillation can be reused as is. In addition, the S-triazine compound obtained is equivalent to that obtained using only an organic solvent, and is a stable compound that does not easily undergo thermal decomposition. This S-triazine compound can be used particularly as a flame retardant for synthetic resins, etc., and is particularly useful as a flame retardant with good thermal stability. Since cyanuric chloride, which is a raw material, is a compound represented by 1, this chlorine can react with the phenolic OH group, and the liberated hydrogen chloride is neutralized with an alkali.

Phenols (1) are HO-<()> It is a compound represented by

R1 is an alkyl group or a halogenated alkyl group having 4 or less carbon atoms, X is a halogen, h and k are each an integer of 0 to 5, and h+k≦5. Monohalogenated phenols or trihalogenated phenols are preferred, and the halogen is bromine or chlorine.
Furthermore, phenols that do not contain halogen can also be used. Others include cresol. Xylenol, halogenated alkyl-substituted phenols, their nuclear halides, etc. can be used. Moreover, the above-mentioned phenols can of course be used alone or in combination of two or more types. Diphenols () are compounds represented by.

R2 is an alkyl group having 4 or less carbon atoms or a halogenated alkyl group, z is a halogen, and S. t. p,.
q is an integer from O to 4, and s+t≦4, p+q≦4
It is. Y is an alkylene group having 5 or less carbon atoms or a halogenated alkylene group, -SO2-, -SO-, -S-,
-O-, -CO-, or none (ie, the aromatic nucleus is directly bonded). Preferably, Y: an alkylene group having 1 to 3 carbon atoms or a halogenated alkylene group, -SO2-, -
0-Z: Br or Cl p,q: An integer from 0 to 2.

Particularly preferably, bisphenol A1 bisphenol S
14.4'-Hydroxydiphenylmethane, and their tetrabromides or tetrachlorides. Other HO-(
Diphenols in which Y is a halogenated alkylene group such as ○H and these tetrahalides, H
Various diphenols can be used, such as diphenols having an alkyl group in the aromatic nucleus, such as OK○》-Y-KU〉-0H and its tetrahalide.

Moreover, the above-mentioned diphenols can of course be used alone or in combination of two or more types. The higher the halogen content of the S-triazine compound used as a flame retardant, the better. Therefore, it is preferable that at least one of the phenols and diphenols contains a halogen (X or Z), and in particular, the number of halogens k + p + q is 3 or more. The compound obtained by reacting the above three raw materials is preferably a compound having a complex structure because it is obtained by condensing a trifunctional compound, a bifunctional compound, and a monofunctional compound. The higher the proportion, the higher the molecular weight.

The reaction ratio is 1 mole of cyanuric chloride to phenols (
3-2&) mol, diphenols a mol (0≦a 1)
As a increases, the molecular weight becomes higher.
However, the number of S-triazine rings in the product is rarely 20 or more and is usually 10 or less. Therefore,
The number of S-triazine rings in the preferred S-triazine compound is 10 or less. Also, in the case of 0kuaku1, S-
A mixture of an S-triazine compound () in which three phenol ([) residues are bonded to a triazine ring and a compound having two or more S-triazine rings is produced. If a=0, S-
Only triazine compound () is available. This S-triazine compound () is effective as a flame retardant when halogenated phenols are used as raw materials. The present invention provides this S-triazine compound () or the S-triazine compound (
) It can also be used in a method for producing S-triazine compounds () containing (). S-triazine compounds (), which are the main products of the present invention, are often mixtures containing complex compounds, especially those with high molecular weights, which include not only linear compounds but also branched compounds. There are also compounds, which are difficult to express in a general formula, but are thought to have a structure roughly as shown below.

R:0H,. R3, R4 or R5, provided that at least one is not an OH group. R1, X, t&K h,. k is the same as Il9-0 () for phenols (1); R5: R6:0H, . R3, R4, or R5, R2, Z,
．． Yls,. t. ．． p,. q is the same as diphenols (). Therefore, when at least one R in the above general formula is R5 and at least one R6 is R5, this S-
The triazine compound () has an infinite molecular weight.

However, like general polycondensation polymers, the molecular weight is not infinite, and in the present invention, the number of S-triazine rings in one molecule is usually 20 or less. As a flame retardant, it is particularly preferable that the number of S-triazine rings in the S-triazine-based compound () is 2 to 10, since if the molecular weight is too high, it may become insoluble and infusible. is appropriate. The number of OH groups in the S-triazine compound () is preferably 0.5 or less per molecule, that is, the number of molecules having one or more hydroxyl groups is preferably less than half of the S-triazine compound (). Especially S-
It is preferred that fewer OH groups are directly bonded to the triazine ring. The solvent used in the reaction must be an organic solvent that uniformly contains water and must be capable of dissolving the reaction raw materials.

For example, cyclic ethers, ketones, alcohols or other organic solvents that are homogeneously miscible with an amount of water. Particularly preferred are cyclic ethers and ketones such as THF. When dissolving the raw materials in this reaction solvent, the temperature must be 5° C. or lower at the step of adding cyanuric chloride. Otherwise, cyanuric chloride will easily react with water to form hydroxyl groups. The three raw materials can be dissolved in a solvent at temperatures below 5°C, but the dissolution rate of phenols and diphenols slows down at low temperatures.
Preferably, the two components are dissolved at room temperature, then cooled, and cyanuric chloride is added at a low temperature. After adding cyanuric chloride, an alkali is added to advance the reaction, but the temperature in this case does not necessarily have to be 5°C or lower. That is, after at least one of the chlorine in cyanuric chloride reacts with phenols or diphenols, the remaining chlorine seems to be less likely to react with water. Furthermore, when adding an alkali, there is a drawback that the reaction rate is slow if the reaction temperature is low. Therefore, it is preferable to carry out the addition of the alkali at room temperature or lower. In addition, as a further improved method, there is a method in which diphenols and cyanuric chloride are first dissolved in a solvent, an alkali is added and reacted, then a phenol is added, and an alkali is further added and reacted.

In this method, it is easy to control the reaction conditions to obtain the desired S-triazine compound with a certain structure, and it is possible to obtain a compound with a relatively narrow molecular weight distribution. In this method as well, it is necessary to maintain the temperature of the system at 5° C. or lower until the cyanuric chloride is dissolved and the alkali is added. The alkali in the present invention is not particularly limited. For example, various alkalis such as alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, basic salts thereof, and aqueous solutions thereof, alkaline earth metal hydroxides, etc. and aqueous solutions thereof can be used. Also, although it is usually not necessary to use a catalyst for the reaction,
When using raw materials with low reactivity or when it is particularly necessary to increase reactivity, a catalyst such as a quaternary ammonium salt can also be used. The S-triazine compound obtained by the present invention is useful as a flame retardant for synthetic resins, synthetic fibers, paper, wood, natural fibers, and the like.

This flame retardant has higher thermal stability than various conventional flame retardants, and is particularly excellent as a flame retardant for synthetic resins. EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples. Example 1 Tetraprombisphenol A (TBA) 13.60f
(0.025 mol), tripromphenol (TBP)
33.60 t (0.10 mol) was placed at 20°C in a 200 ml glass four-bottle flask equipped with a reflux, a thermometer, a dropping load, and a stirrer, and tetrahydrofuran (THF
)94V and 6f of water were added and cooled to 0°C while stirring, and at that temperature 9.22f (0.05 mol) of cyanuric chloride was added.
Add and stir until homogeneous.

Thereafter, 12.481 (0.156 mol) of a 50 wt % NaOH aqueous solution was gradually added dropwise to the reaction solution using a dropwise load while maintaining the temperature of the reaction solution at 10° C. or lower. After finishing dropping 3
The temperature of the reaction solution was kept at 10° C. or lower for 0 minutes, and then raised at a rate of 10° C./hour until it reached reflux.

After keeping at reflux temperature for 3 hours, the reaction solution was filtered and 2
1! The precipitate was reprecipitated into 0.0 methanol.
It was washed successively with 200ml of 1N hydrochloric acid, 111ml of water, and 200ml of methanol. After drying, the yield of white powder was 47.05 tons and the bromine content was 63.9%. The number average molecular weight measured using a THF solution using a vapor pressure method was 2,300. In addition, KOH-ethanol solution,
As a result of neutralization titration using the indicator phenolpthalene, 1
It contained an average of 0.02 acidic groups per molecule. Furthermore, the thermal decomposition initiation temperature of this material (TG- manufactured by Rigaku Denki Co., Ltd.
DSC standard type, heating rate of 10°C/hour under air flow) was 328°C. Comparative Example TBAl3.6OV (0.025 mol), TBP33.
6Ot (0.10 mol), cyanuric chloride 9.22t (0
．． 05 mol) was placed in the same flask as in Example 1 at 20°C, and THFlOOf was added.

The reaction solution was cooled to 5° C. with stirring, and 12.48 V of a 50 wt % NaOH aqueous solution was gradually added dropwise from a dropwise load while ensuring that the temperature of the reaction solution did not exceed 10° C. Thereafter, a white powdery product was obtained by the same operation as in Example 1. The yield of this product was 47.5 tons and the bromine content was 64.0%. Also, the number average molecular weight is 28
The average number of acidic groups per molecule of 001 was 0.04, and the temperature at which thermal decomposition started was 351°C. The water-THF azeotrope obtained by distilling the water-containing THF used in this reaction is THF.
It consists of 94 parts by weight of HF and 6 parts by weight of water.

This azeotrope was then used as a solvent for reuse. That is, the same operation as above was performed using a mixed solvent of THF947 and 6 tons of water instead of THF1OOf to obtain a white powder.
The yield was 39.5f1 and the bromine content was 61.3%.
Further, the number average molecular weight was 150,011, and the average number of acidic groups was 0.88 per molecule, and the thermal decomposition initiation temperature was 158°C. IZ Example 2 Tetraprombisphenol A (TBA) 21.761
(0.04 mol) into a 200 m1 glass four-loop flask equipped with a reflux, thermometer, drop load, and stirrer.
℃, tetrahydrofuran (THF) 56.47
and water 3.601, and cooled to 0°C while stirring,
9.22 t (0.05 mol) of cyanuric chloride was added and stirred until homogeneous.

After that, 50 wt% NaOH aqueous solution 6.407 (0.08 mol) was added dropwise to the reaction solution at a temperature of 10°C.
It was gradually dropped while keeping the temperature below. After the dropwise addition was completed, the temperature was kept below 10°C for 30 minutes while stirring, and then 23.16f of tripromphenol (TBP) was added. (0.07 mol) T
A solution dissolved in a mixed solvent of 37.6f HF and 2.40V of water was added. Then, NaO is further added by dropwise loading.
6.00 f (0.075 mol) of H5Owt% aqueous solution was gradually added dropwise while keeping the temperature of the reaction solution below 10°C. After dropping, keep at 10℃ or below for 30 minutes, then 10℃
The temperature of the reaction solution was raised to reflux by increasing the temperature at a rate of /hour. After being kept at reflux temperature for 3 hours, it was cooled and the reaction solution was filtered. The filtrate was added to a solvent consisting of 5007 isopropyl alcohol and 68f water to produce a precipitate, which was filtered and washed with a reprecipitation solvent and water. The yield of white powder obtained after drying was 45.127, and the bromine content was 60.60%.

The number average molecular weight of this product measured using a vapor pressure method in a THF solution was 4,800. Further, as a result of neutralization titration using a KOH ethanol solution and an indicator phenolpthalene, it was found that each molecule contained an average of 0.03 acidic groups. Furthermore, the thermal decomposition onset temperature of this product was 331°C. Example 3 Tetrachlorbisphenol Al6.47t (0.04
5 mol), trichlorophenol 13.65f (0.0
60 mol) was placed at 20°C in a 300ml glass four-bottle flask equipped with a reflux, a thermometer, a dropping load, and a stirrer, 94l of THF and 6V of water were added, and the mixture was cooled to 0°C with stirring, and the chlorination reaction was carried out at that temperature. Cyanuric 9.22t (0.05
mol) and stir until uniform.

After that, 12.48 t (0.156 mol) of a 50 wt% NaOH aqueous solution was added dropwise to the reaction solution at a temperature of 1.
It was gradually added dropwise while maintaining the temperature at 0°C. After the dropwise addition was completed, the temperature of the reaction solution was kept at 10° C. or lower for 30 minutes, and then the temperature was raised at a rate of 10° C./hour until the temperature of the reaction solution reached reflux.

After being kept at reflux temperature for 3 hours, the reaction solution was filtered;
The precipitate was reprecipitated into 0.21 methanol and the resulting precipitate was added to 0.
200ml of 1N hydrochloric acid water, 1f of water! , methanol 200
Washed sequentially with m1. The yield of white powder obtained after drying was 28.357, and the chlorine content was 37.9%. number? The average molecular weight is 6100, and the number of acidic groups per molecule is 0.
Thirteen pieces had a thermal decomposition onset temperature of 322°C. Example
4 to 7 S-triazine compounds were produced in the same manner as in Example 1 using the raw materials listed in the table below (Examples 4 to 6).

Claims (1)

[Scope of Claims] 1. Cyanuric chloride, and phenols (3-2a) represented by the following (I) per 1 mol of the cyanuric chloride.
mol and a mol of diphenols represented by (II) below (
However, in the method for producing the S-triazine compound represented by (II) below by treating 0≦a<3/2) with 3 equivalents or more of alkali, the solvent used must uniformly contain water. 1. A method for producing an S-triazine compound, which is an organic solvent, and the temperature of the reaction system is maintained at 5° C. or lower from the time cyanuric chloride is dissolved in the solvent until the alkali treatment is started. (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ R^1: Alkyl group with 4 or less carbon atoms or halogenated alkyl group X: Halogen (II) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ R^2: Carbon Alkyl group or halogenated alkyl group Z of number 4 or less
:Halogen Y: Alkylene group having 5 or less carbon atoms or halogenated alkylene group, -SO_2-, -SO-, -S-, -O-
, -CO-, or none (i.e., aromatic nucleus is directly bonded) s,
t, p, q: each integer from 0 to 4, s+p≦4, t+q≦
4 (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼R:OH
, R^3, R^4, or R^5, but at least 1
One is not OH. R^3: ▲There are mathematical formulas, chemical formulas, tables, etc.▼R^1, X
, h, k are the same as (I) R^4: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ R^2, Z
, Y, s, t, p, q are the same as (II) R^5: ▲ Formula,
There are chemical formulas, tables, etc.▼R^6:OH, R^3, R^
4 or R^5, R^2, Z, Y, s, t, p, q are the same as (II), but S-triazine compound (III)
The number of S-triazine rings in does not exceed 20. 2. The method for producing an S-triazine compound according to claim 1, wherein the solvent is a cyclic ether or ketone containing water uniformly. 3. The method for producing an S-triazine compound according to claim 1, wherein a is not 0. 4. The method for producing an S-triazine compound according to claim 1, wherein a is 1/2 or more. 5. Production of an S-triazine compound according to claim 1, wherein the phenol (I) is ▲ has a mathematical formula, chemical formula, table, etc. ▼ X: Br or Cl, k: an integer from 0 to 3 Method. 6. The method for producing an S-triazine compound according to claim 5, wherein the phenol (I) is tribromophenol or monobromophenol. 7 Diphenols (II) are ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Z: Br or Cl Y: Alkylene group with 1 to 3 carbon atoms or halogenated alkylene group, -SO_2-, or -O-p, q : Each is an integer from 0 to 2. Claim 1
A method for producing an S-triazine compound. 8 Diphenols (II) are tetrabromobisphenol A, tetrabromobisphenol S or 3.3'
- The method for producing an S-triazine compound according to claim 7, characterized in that it is 5,5'-tetrabromo-4,4'-dihydroxydiphenylmethane. 9 Phenols (I) and diphenols (II)
The total number of halogens bonded to aromatic nuclei in (i.e., k+
The method for producing an S-triazine compound according to claim 1, wherein p+q) is 3 to 7. 10 The S-triazine compound (III) according to claim 1, characterized in that the product is an S-triazine compound (III) in which the number of S-triazine rings is 2 to 10. Method of manufacturing the compound. 11 Acidic O in S-triazine compound (III)
2. The method for producing an S-triazine compound according to claim 1, wherein the number of H groups per molecule is 1/2 or less.