RU2245856C1 - Method for production of plasticizer - Google Patents

Abstract

FIELD: high effective plasticizer for concrete mixes.

SUBSTANCE: claimed method includes sulfonation of naphthalene cut from petrochemical process, in particular naphthalene cut of process stream from benzene production, followed by condensation with formaldehyde and neutralization of obtained product with alkali. Naphthalene cut contains (mass %) naphthalene 96.4-99.5; methylnaphtalene 0.01-0.2; biphenyl 0.001-0.1; low boiling additives (e.g. alkyl benzene, methylinden, tetralin_ 0.5-3.6.

EFFECT: enhanced raw base for production of concrete mix plasticizers.

4 cl, 1 tbl

Description

The present invention relates to a method for producing a highly effective plasticizer of concrete mixtures, the so-called “superplasticizer”.

Superplasticizers are additives that allow you to adjust the rheological and physico-mechanical properties of concrete mixtures and concretes.

When introduced into the concrete mixture, superplasticizers increase its mobility until the cone settles more than 20 cm. In this case, the strength of the concrete obtained remains equal to or close to the strength of concrete obtained from the mixture of initial mobility.

Fields of application of superplasticizers are the production of reinforced concrete products (slabs, panels, pressure pipes, etc.) and massive densely reinforced structures, the construction of monolithic reinforced concrete structures, the manufacture of floors and coatings with high performance properties.

According to the plasticizing effect, the most effective are superplasticizers based on alkali neutralized condensation products of naphthalene sulfonic acid and formaldehyde (Ortega G. A. Cemento-Hormigon, 1980, v. 51, No. 559, p. 537-548).

The need for these plasticizers is several hundred thousand tons per year.

Condensation products of naphthalenesulfonic acid and formaldehyde are advisable to use as additives to building materials, such as cements, plaster, hydraulic lime, air lime, gypsum, anhydride and magnesia binders.

The industry also produces various brands of modifiers for cement and concrete mixtures, the basis of which are the condensation products of naphthalenesulfonic acid and formaldehyde. As additives to them, individual compounds are used, for example, sodium formate, sodium nitrite, and others, and various mixtures, for example, additives based on lignosulfonates and higher alcohols, and others.

Additives to plasticizer are introduced in agreement with the consumer.

The main type of raw material in the production of plasticizers for concrete mixtures is coke-chemical naphthalene (GOST 16106-82).

Since the resources of coke-chemical naphthalene are limited, studies have been carried out on the use of coke-chemical naphthalene fractions, press outflows and naphthalene oils. The possibility of using coke chemical naphthalene with a low content of the basic substance, but not less than 93 wt.% (T.Ya. Gogoleva et al. Coke and Chemistry, 1991, No. 2, pp. 22-24) was tested. When using naphthalene fractions, phenols and pyridine bases are undesirable impurities.

The main raw material in the production of plasticizers for concrete mixtures is currently coke-chemical naphthalene with a crystallization temperature of more than 79.0 ° C.

A known method of preparing a plasticizer, which consists in the condensation of a salt of an alkaline or alkaline earth metal naphthalene sulfonic acid with formaldehyde (US Patent No. 3686133, B 01 f 17/00, C 04 B 13/00, publ. 08/22/1972).

A widely used method of preparing a plasticizer for concrete mix (G.D. Kharlampovich, A.A. Kaufman Technology of coke production, Moscow, publishing house "Metallurgy", 1995, p. 342-343), which includes the following stages:

- sulfonation of naphthalene with sulfuric acid at a temperature of 130-165 ° C;

- exposure of sulfomass with blowing of unreacted naphthalene;

- condensation of sulfonation products with formaldehyde at atmospheric or elevated pressure and a temperature of 100-130 ° C;

- neutralization of condensation products with alkali, dilution.

Closest to the claimed technical essence is a method of producing a plasticizer for concrete mix (RU 2054401 C1, Scientific and Production Association "SynthesisPAW", C 04 V 24/22, publ. 02.20.1996).

The known method includes sulfonation of petrochemical waste products based on aromatic hydrocarbons, followed by condensation with formaldehyde and neutralization of the resulting product. As a petrochemical production waste, naphthalene-based ethylene production waste is used.

The objective of the present invention is to expand the range of raw materials for plasticizers for concrete mixtures.

The essence of the invention lies in the use of the naphthalene fraction of the petrochemical industry as a feedstock, having the following composition, wt.%:

naphthalene 96.4-99.5

methylnaphthalenes 0.01-0.2

diphenyl 0.001-0.1

low boiling impurities, including

including alkylbenzenes, methyl

indene, tetralin, etc. 0.5-3.6

The naphthalene fraction of petroleum origin of the specified composition is obtained by distillation or crystallization of the naphthalene fraction from the process streams of benzene production.

A method of obtaining a plasticizer of concrete mixtures according to the invention includes the following stages:

- sulfonation of the naphthalene fraction of the specified composition with sulfuric acid at a temperature of 130-160 ° C with a mass ratio of sulfuric acid and naphthalene fraction 1: (1.03-1.3);

- condensation of sulfonation products with formaldehyde at atmospheric or elevated pressure, a temperature of 100-130 ° C and a molar ratio of formaldehyde and naphthalene sulfonic acid (0.94-1.6): 1

The technological parameters of the stages of sulfonation and condensation of the claimed method are traditional and generally accepted.

The proposed method for producing a plasticizer is illustrated by the following examples.

Example 1

Sulfonation of the naphthalene fraction containing, wt.%: Naphthalene 99.489, methylnaphthalene 0.01, diphenyl 0.001, low-boiling impurities 0.5.

Sulfonation of the naphthalene fraction of the specified composition was carried out in a cast-iron apparatus with a volume of 6.3 m ³ with a stirrer and a jacket for supplying a coolant.

After loading the naphthalene fraction and heating to 130-140 ° C, the supply of 92-94% sulfuric acid was started at a mass ratio of sulfuric acid and naphthalene fraction of 1: 1.2. Sulphonation was continued for ~ 1.5 hours at a temperature not exceeding 160 ° C. Next, the mass in the apparatus was kept at a temperature of 165 ° C for 3 hours with stirring.

Free naphthalene was blown off with direct steam at a pressure of P = 3 atm.

Condensation was carried out in a steel enameled apparatus equipped with a stirrer and a jacket, a 35-36% aqueous formalin solution for 2.5-3.5 hours at a temperature of 110-120 ° C and a pressure of ~ 1.5 atm. The molar ratio of formaldehyde to naphthalenesulfonic acid is 1: 1. Exposure at a temperature of 120-130 ° C for ~ 1.5 hours.

At the end of the exposure, dilution water was supplied to the apparatus.

The neutralization of the reaction mass was carried out with 44% sodium hydroxide solution to a pH of 7-9.

Quality indicators and test results of the obtained plasticizer are shown in the table.

Example 2

Sulfonation of the naphthalene fraction containing, wt.%: Naphthalene 96.4, methylnaphthalene 0.01, diphenyl 0.001, low boiling point impurities 3.589.

The preparation of the plasticizer was carried out under the conditions of example 1.

Quality indicators and test results of the obtained plasticizer are shown in the table.

Example 3

Sulfonation of the naphthalene fraction containing, wt.%: Naphthalene 98.35, methylnaphthalene 0.1, diphenyl 0.05, low boiling point impurities 1.5.

The preparation of the plasticizer was carried out under the conditions of example 1.

Quality indicators and test results of the obtained plasticizer are shown in the table.

Example 4

Sulfonation of the naphthalene fraction containing, wt.%: Naphthalene 94.6, methylnaphthalene 0.1, diphenyl 0.01, low boiling point impurities 5.29.

The preparation of the plasticizer was carried out under the conditions of example 1.

During the process, deviations were observed at the stages of sulfonation (increased deoxidation of sulfuric acid) and condensation (thickening of the reaction mass).

Quality indicators and test results of the obtained plasticizer are shown in the table.

As follows from the table, the resulting product in the presence of plasticizing properties does not meet the requirements of GOST.

Table
Plasticizer quality and test results No. p.p. The name of indicators TU 6-36-0204229-625-90 Example Number 1 2 3 4 1 Appearance W brown colors W brown colors W brown colors W brown colors W brown colors 2 Mass fraction of active substances in terms of dry product,%, not less 69 69 70 71 67 3 Mass fraction of water,%, no more 68 67 67 66.5 67 4 The activity index of hydrogen ions (pH) of an aqueous solution with a concentration of 2.5 wt.% 7-9 7 8.4 7.6 7.3 5 Draft of a cone, not less than, cm twenty 21 twenty 21 eighteen 6 Compressive strength,
kgf / cm ² 348-390 349 350 440 330 Note: compressive strength according to GOST 30459-96 “Methods for determining the effectiveness of additives”.

Claims (1)

A method of producing a plasticizer for a concrete mixture, including sulfonation of a naphthalene fraction of a petrochemical production followed by condensation with formaldehyde and neutralization with an alkali of the obtained product, characterized in that a naphthalene fraction of a petrochemical production using a naphthalene fraction of a benzene production stream of the following composition, wt.%: Naphthalene 96.4-99.5 Methylnaphthalenes 0.01-0.2 Diphenyl 0.001-0.1 Low boiling impurities, including alkylbenzenes, methylindene tetralin 0.5-3.6