JPH11302049A - Production of slurry dispersant, and dispersant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a formaldehyde condensation product without impairing its dispersing performance with high productivity by specifying the amt. of water for condensation present in a reaction system at the time of the condensation reaction of a liq. sulfonation reaction product of naphthalene and formaldehyde. SOLUTION: When a liq. sulfonation reaction product of naphthalene and formaldehyde are condensed under elevated pressure of an inert gas, the amt. of water for condensation is adjusted to 7.5-8.0 times (by mol) the amt. of the naphthalene compd. and the objective slurry dispersant is produced. A formaldehyde condensation product having a number average mol.wt. of 1,200-1,500, a wt. average mol.wt. to number average mol.wt. ratio of 5.0-7.5, a high condensation degree and a sharp mol.wt. distribution can be produced in a short time. The liq. sulfonation reaction product of naphthalene preferably contains <=5 mol.% unreacted naphthalene and <=5 mol.% naphthalenedisulfonic acid as a by-product. Formaldehyde is preferably used by 0.8-1.2 mol per 1 mol naphthalene compd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates generally to a method for producing a naphthalenesulfonic acid formalin condensate (hereinafter simply referred to as formalin condensate) and salts thereof, and more particularly to a method for preparing a specific sulfonation reaction solution as a raw material, The present invention relates to a method for producing a formalin condensate which is condensed under an inert gas pressure in the presence of water and salts thereof.

[0002]

2. Description of the Related Art Conventionally, formalin condensates and salts thereof have been
It is produced by sulfonating naphthalene with sulfuric acid and then condensing with formalin, and then neutralizing the formalin condensate with an alkali metal hydroxide or carbonate or the like (JP-B-41-11737, JP-B-48-48). 95
No. 64, etc.). It is also known that a formalin condensate that is highly condensed and has a sharp molecular weight distribution exhibits excellent performance as, for example, a dispersant such as cement.

In the conventional sulfonation step, naphthalene and an excess molar amount of a sulfonating agent are reacted at about 160 ° C. for 2 to 6 hours. However, when the molar ratio of naphthalene to concentrated sulfuric acid is close to 1, When unreacted naphthalene remains and by-produced dinaphthyl sulfone is generated, and when fuming sulfuric acid or sulfuric anhydride is used as a sulfonating agent, the amount of unreacted naphthalene is relatively reduced, Since the sulfonating ability of the sulfonating agent is too high, polysulfonic acids such as naphthalenedisulfonic acid are by-produced as a result.

Then, in the above-mentioned step of condensing the sulfonated product with formalin, sulfuric acid is used as a catalyst in an amount of about 0.7 to 0.8 with respect to the total moles of the naphthalene compound in the reaction system.
The reaction had to be carried out at a molar ratio of 95 to 100 ° C. for 20 hours or more. To control the condensation reaction, it is necessary to control various factors such as the amount of sulfuric acid, the amount of formalin, the amount of water, the reaction temperature and the reaction time, and these factors are the dispersing performance of the formalin condensate and its salt, for example, It greatly affects the dispersing performance for cement.

In the step of condensing the naphthalene sulfonate obtained in the above sulfonation step with formalin, if there is a large amount of unreacted naphthalene, the naphthalene is preferentially incorporated into the formalin condensate and the resulting formalin condensate is obtained. Is a formalin condensate having poor dispersing performance as a dispersant for cement. On the other hand, if the reaction product contains a large amount of naphthalene polysulfonic acid, the polysulfonated product hardly participates in the condensation reaction with formalin, and has little dispersibility in cement itself. However, similar to the former, there is a problem that the dispersing performance of the cement as a dispersant is lowered.

As described above, in order to obtain a formalin condensate excellent in dispersibility in cement, it is required that the obtained formalin condensate has a sharp molecular weight distribution. It is important for the molecular weight distribution of the formalin condensate to maintain a uniform stirring state during the formalin condensation reaction.For example, when the viscosity of the reactant increases during the formalin condensation reaction and stirring is difficult, water is added. In addition, non-uniform stirring is prevented by facilitating stirring or by adding water in advance. From the above, when the obtained formalin condensate tries to satisfy the high dispersibility with respect to cement, a long-time reaction is forced from an increase in the amount of water used, while the amount of water in the system is small. In this case, there is a problem that a low-performance formalin condensate having a wide molecular weight distribution is produced by a heterogeneous condensation reaction.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a formalin having higher performance and higher productivity required for a slurry dispersant such as cement, and more particularly as a dispersant for cement and mortar. An object of the present invention is to provide a method for producing a condensate.

[0008]

The above object is achieved by the present invention described below. That is, in the present invention, when the sulfonation reaction solution of naphthalene and formalin are condensed under an inert gas pressure, the water for condensation is adjusted to 7.5 to 8.0 times mol with respect to the total mol number of the naphthalene compound. A method for producing a slurry dispersant comprising a naphthalenesulfonic acid formalin condensate as a main component.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, when condensing a sulfonated product of naphthalene with formalin under an inert gas pressure, the number of moles of the naphthalene nucleus in the reaction system is reduced. When a certain amount of water for condensation is used, the performance as a cement dispersant is not impaired at all, that is, the number average molecular weight is from 1,200 to 1,500.
And the weight average molecular weight / number average molecular weight is 5.0 to 5.0.
It has been found that a formalin condensate having a high condensation of 7.5 and a sharp molecular weight distribution can be obtained, and that the formalin condensate can be produced in an extremely short time as compared with the conventional method.

[0010]

Next, the present invention will be described in more detail with reference to preferred embodiments. In the sulfonation reaction product of naphthalene used in the present invention, it is desirable that unreacted naphthalene and naphthalenedisulfonic acid by-produced are each 5 mol% or less, preferably 3 mol% or less, per mole of all naphthalene compounds. . A sulfonated reactant containing such a low molar ratio of unreacted naphthalene and naphthalenedisulfonic acid can be produced as follows.

For example, as a preferred example, a predetermined amount of naphthalene is charged into an autoclave equipped with a thermometer, a pressure gauge and a stirrer, heated and melted at 80 to 90 ° C., and a predetermined amount of a sulfonating agent is supplied to a pump. Into the autoclave over 5 minutes. Then, pressurize with an inert gas,
By raising the temperature to 50 ° C. and then aging for 3 hours, a target sulfonation reaction solution is obtained.

The naphthalene used in the sulfonation reaction is preferably a pure naphthalene, but may be a crude naphthalene as long as the dispersibility of the finally obtained formalin condensate in a slurry is not impaired. In this way, a sulfonated product of naphthalene is obtained in which the amount of unreacted naphthalene and by-product naphthalenedisulfonic acid is 5 mol% or less, preferably 3 mol% or less, respectively, per mole of all naphthalene compounds.

The sulfonating agent used in the above reaction is S
Although fuming sulfuric acid, concentrated sulfuric acid and sulfuric acid having an O ₃ concentration of 5% or less are used, it is preferable to use concentrated sulfuric acid. SO ₃ concentration of 5
When fuming sulfuric acid is used in an amount of more than 10%, a large amount of by-product naphthalenedisulfonic acid is produced, so that it is difficult to obtain a sulfonated reaction product having the above composition. The inert gas used in the sulfonation reaction is an inert gas such as carbon dioxide, air, nitrogen, helium, argon, etc., at a gauge pressure of 0.5 to 10 kg /.
It is desirable to pressurize to ² cm ² G, preferably 1-2 kg / cm ² G. The reaction temperature is from 130 to 170C, preferably from 140 to 150C. Reaction time is 30 minutes to 6
Hours, preferably 1 to 3 hours.

In the present invention, the above-mentioned sulfonation reaction solution is cooled to 100 ° C. or lower to return the pressure to the atmospheric pressure, or water, formalin and concentrated sulfuric acid are sequentially added to the sulfonation reaction solution under a pressurized state. The mixture is added to carry out a condensation reaction to produce a formalin condensate. In order to shorten the production time,
It is desirable to add a predetermined amount of any of water, formalin and concentrated sulfuric acid to the reaction system within 5 minutes.

The formalin used in the method of the present invention is 0.8 to 1.2 mol, preferably 0.95 to 1.05 mol, per mol of the naphthalene compound, and the catalytic sulfuric acid is used for 1 mol of the naphthalene compound. 0 to 1 mol, preferably 0.3 to 0.6 mol, and water is 7.5 to 8.0 mol per 1 mol of the naphthalene compound. In addition, water is mixed so as to have the above molar ratio in consideration of water produced by sulfonation and water in formalin. In particular, the amount of water used is important.If the amount of water used is less than the above range, the reaction solution becomes highly viscous, the heterogeneous condensation reaction proceeds, the proportion of high molecular weight condensates increases, and the cement dispersant On the other hand, if the amount of water used exceeds the above range, a condensate satisfying the performance as a cement dispersant can be obtained, but the reaction rate decreases. And the productivity is insufficient.

When a predetermined amount of water, formalin and concentrated sulfuric acid are blended, the reaction mixture is pressurized with an inert gas at normal pressure. As for the pressurization, as in the case of the sulfonation, an inert gas such as carbon dioxide, air, nitrogen, helium, or argon can be used as the inert gas, and the gauge pressure is 0.5 to 10 kg / g.
It is desirable to pressurize to ² cm ² G, preferably 2 to 5 kg / cm ² G. When the pressure is less than 0.5 kg / cm ² G,
Due to the foaming phenomenon and the swelling of the liquid surface during the condensation reaction, the stirring state of the reaction solution is deteriorated, and a non-uniform condensation reaction is caused, and it is difficult to obtain a preferable formalin condensate from the viewpoint of dispersion performance with respect to the slurry. On the other hand, pressurization is 10 kg / cm ² G
If it exceeds, it is not practical in terms of equipment economy. Thereafter, the reaction temperature is set to 120 to 160 ° C, preferably 130 to 160 ° C.
Raise the temperature to 140 ° C.

The reaction time of the formalin condensation is 1 to 10 hours, preferably 3 to 6 hours. After completion of the reaction, a predetermined amount of water is added to adjust the reaction mixture to a target concentration, and the mixture is led to a salt of a formalin condensate by a neutralization operation. Neutralization may be carried out with sodium hydroxide, or lime siding may be performed. The salt of the formalin condensate obtained according to the present invention may be used in the form of K, NH ₄ , Ca, organic amine and double salts thereof in addition to Na salt. When the molecular weight distribution of the thus obtained formalin condensate is measured, the number average molecular weight is 1,200 to 1,500 and the weight average molecular weight / number average molecular weight corresponds to the range of 5.0 to 7.5. The formalin condensate obtained in the present invention is particularly useful as a dispersant when slurrying cement, mortar and the like.

[0018]

Next, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited thereto. In the following description, “%” is based on weight unless otherwise specified. Example 1 An autoclave equipped with a stirrer, a thermometer and a pressure gauge was charged with 135 g (1 mol) of crude naphthalene, and 90 g of the crude naphthalene was charged.
~ 100 ° C and melted with 98% sulfuric acid 130g (1.3g)
Mol) was pumped into the autoclave over 5 minutes. Next, after pressurizing with nitrogen gas until the gauge pressure reached 2 kg / cm ² G, the temperature was raised to 150 ° C. in 1 hour, and the reaction was carried out at the same temperature for 3 hours. By this sulfonation reaction, a sulfonation reaction solution consisting of 2.5% of unreacted naphthalene and 3.3% of naphthalenedisulfonic acid (all in mol%) was obtained.

Next, 70 g (3.9 mol) of water, 98% sulfuric acid 2
0 g (0.2 mol) and 81 g of 37% formalin aqueous solution
(1 mol) were pumped sequentially into the reactor within a few minutes. Thereafter, the reaction solution at 90 ° C. was added at 1 ° C./min. And reacted at 130 ° C. for 4 hours. The reaction mixture after the condensation was neutralized by liming sodading, and then the concentration was adjusted to obtain an aqueous solution of a soda salt of a formalin condensate having a solid concentration of 40%.

Comparative Example 1 In an autoclave equipped with a stirrer, a thermometer and a pressure gauge, 135 g (1 mol) of crude naphthalene was charged, and 90
Melted by heating to ~ 100 ° C, 123% fuming sulfuric acid 123g
(1.3 mol SO ₃ equivalent) was pumped into the autoclave over 5 minutes. Then, the temperature was raised to 160 ° C. in one hour, and the reaction was carried out at the same temperature for three hours. A sulfonation reaction solution comprising 2.2% of unreacted naphthalene and 9.7% of naphthalenedisulfonic acid (all by mol%) was obtained by the sulfonation reaction.

While stirring the above sulfonated liquid, water 77
g (4.3 mol), 20% (0.2 mol) of 98% sulfuric acid and 85 g (1.00 mol) of a 37% aqueous formalin solution were sequentially pumped into the reactor within several minutes. Then, after pressurizing with nitrogen gas until the gauge pressure becomes 3 kg / cm ² G, the reaction solution at 90 ° C. is then heated at 1 ° C./min. At 130 ° C. for 1 hour. The condensed product was neutralized by liming sodading, and the concentration was adjusted to obtain an aqueous solution of a soda salt of a formalin condensate having a solid concentration of 40%.

Examples 2 to 7 and Comparative Examples 2 to 3 Example 1 was repeated except that the feed ratio of raw materials and the reaction conditions were changed.
A formalin condensate was produced in the same manner as described above. Table 1 shows the charging ratios and the reaction conditions of the raw materials of Examples 2 to 7 and Comparative Examples 2 to 3. Table 2 shows the number average molecular weight and molecular weight distribution of the obtained formalin condensate. The average molecular weight was measured by gel permeation chromatography (polystyrene conversion).

[0023]

Table 1 Table 1: Production conditions for sulfonation and formalin condensate N: Number of moles of naphthalene ring S: Number of moles of sulfonating agent W: Total number of moles of reactants in condensation reaction system F: Number of moles of formalin

[0024]

[Table 2] Table 2: Measurement results of molecular weight

The following tests were conducted on the formalin condensates obtained in the above Examples and Comparative Examples. [Concrete test] (1) Raw materials used Water: tap water Cement: ordinary Portland Three different producers (Nippon Cement, Chichibu Onoda Cement, Sumitomo Osaka Cement)
An equivalent blend of the above. Fine aggregate: Mountain sand producing area: Kimitsu, Chiba Prefecture Coarse aggregate: Limestone crushed stone producing area: Bird shape, Kochi Dispersant: Formalin condensate (dispersed) obtained in Examples 1 to 7 and Comparative Examples 1 to 3 Agent) (40% aqueous solution)

[0026] (2) blending unit cement content of concrete: 320 kg / m ³ Unit water: 170 kg / m ³ fine aggregate: 880 kg / m ³ Coarse aggregate: 1,000kg / m ³ dispersant additive amount: 1.3 % (Amount of cement) The blending was determined by trial kneading according to JIS A6204 “Chemical admixture for concrete” with a slump value of 18 ± 1 cm after kneading.

(3) Test method The raw materials used in the above (1) were kneaded with a 30 L twin-screw forced stirring mixer for 90 seconds under the mixing conditions in the above (2). In the test, a water reduction rate measurement and a compressive strength test of the hardened concrete were performed, and each sample was evaluated for a water reduction rate and a compressive strength ratio specified by JISA6204. Table 3 shows the results of measuring the water reduction rate using concrete, and Table 4 shows the results of measuring the compressive strength.

[0028]

[Table 3] Table 3: Measurement results of water reduction rate by concrete Note) Criteria: No water, cement, fine aggregate, and coarse aggregate are blended so that a predetermined slump value (18 ± 1 cm) is obtained without adding a dispersant.

[0029]

Table 4: Results of compressive strength test using concrete Note) Criteria: No dispersing agent added, water, cement, fine aggregate, and coarse aggregate blended to achieve a predetermined slump value (18 ± 1 cm).

[0030]

According to the method for producing a slurry dispersant of the present invention, the reaction time can be extremely shortened without impairing the dispersing performance by adjusting the amount of water for condensation present in the system during the condensation reaction to a specific amount. be able to. The obtained dispersant has a desirable performance required for a dispersant for cement and mortar as a slurry dispersant.

Claims (6)

[Claims] 1. When condensing a sulfonation reaction solution of naphthalene and formalin under an inert gas pressure, the water for condensation is adjusted to 7.5 to 8.0 times the total number of moles of the naphthalene compound. A method for producing a slurry dispersant containing a naphthalenesulfonic acid formalin condensate as a main component. 2. The slurry dispersant according to claim 1, wherein the sulfonated reaction product of naphthalene contains unreacted naphthalene and by-produced naphthalenedisulfonic acid in a proportion of 5 mol% or less based on the total number of moles of the naphthalene compound. Manufacturing method. 3. Formalin is 0.8 to 1.2 mol per mol of naphthalene compound, catalyst sulfuric acid is 0.3 to 0.6 mol per mol of naphthalene compound, and water is 1 mol of naphthalene compound. The method for producing a slurry dispersant according to claim 1, wherein the slurry dispersant is used in a ratio of 7.5 to 8.0 moles. 4. The method for producing a slurry dispersant according to claim 1, wherein a predetermined amount of any of water, formalin and concentrated sulfuric acid is added to the reaction system within 5 minutes. 5. An inorganic or organic powder dispersant comprising the naphthalene sulfonic acid formalin condensate according to claim 1 as a main component. 6. The dispersant according to claim 5, wherein the naphthalenesulfonic acid formalin condensate has a molecular weight of 1,200 to 1,500 and a molecular weight distribution of 5.0 to 7.5.