CN101376639B - Method for coproduction of dispersants MF and sodium sulphite - Google Patents

Abstract

The invention discloses a method for producing dispersant MF and co-producing sodium sulfite, comprising: adding sulfuric acid with a concentration of more than 95% to the raw material of methylnaphthalene, feeding sulfur trioxide to carry out sulfonation reaction, and raising the temperature after the sulfur trioxide fully reacts , vacuumize, and continue to react until the total acidity of the solution is 22% to 27%; the sulfur dioxide gas produced by the sulfonation reaction is absorbed with lye to prepare sodium sulfite; the solution after the sulfonation reaction is added with water to adjust the condensation acidity to 14% to 20%, and then Formaldehyde aqueous solution is condensed, after the condensation is completed, it is diluted, and alkali is added to adjust the pH value to neutral to obtain the dispersant MF. The process of the invention does not need to use lime for neutralization, so solid wastes such as calcium sulfate will not be produced, and the quality can reach the Chinese quality standard GB9294-88. At the same time, sulfur dioxide waste gas has also been reasonably recycled, turning waste into treasure, featuring low energy consumption, and is a clean and environmentally friendly production process.

Description

A kind of method of producing dispersant MF and co-producing sodium sulfite

technical field

The invention relates to a method for preparing a sulfonated dispersant, in particular to a method for producing the dispersant MF and simultaneously producing sodium sulfite.

Background technique

Dispersant MF is the most commonly used dye dispersant for disperse dyes and vat dyes in the world. It is popular because of its good dispersing effect and low price.

The usual production process of dispersant MF is to use industrial methylnaphthalene (methylnaphthalene content above 60%) or washing oil (methylnaphthalene content above 25%) to sulfonate with concentrated sulfuric acid, then condense with formaldehyde aqueous solution, and then Use lime to neutralize the residual sulfuric acid, make alkali through sodium hydroxide, and then filter off solid waste such as calcium sulfate to obtain an aqueous solution of methylnaphthalenesulfonic acid formaldehyde condensate, that is, dispersant MF.

The existing technology usually uses about 98% concentrated sulfuric acid as the sulfonating agent, and its disadvantage is that it will produce a large amount of residual waste acid, which needs to be neutralized with lime, and solid waste such as calcium sulfate will be produced. At the same time, sulfonation will generate a large amount of sulfur dioxide, thereby affecting the environment.

The Chinese invention patent with the publication number CN1081451 uses concentrated sulfuric acid as a sulfonating agent, uses organic solvents (usually benzene substitutes, such as benzene, toluene, etc.) Acidity followed by condensation. This method needs to use recycled materials to adjust the acidity, and to recover the organic solvent, the process is more complicated, and the organic solvent is not completely inert, it will consume a certain amount of sulfonating agent, generate a certain amount of harmful by-products, which are difficult to separate, thus affecting the product quality. The Chinese invention patent with the publication number CN1043637 uses sulfur dioxide as a solvent, sulfonates it with sulfur trioxide, and then recovers the solvent sulfur dioxide and removes the residual sulfur dioxide with nitrogen. At the same time, there will be more residual sulfur dioxide in the sulfonated product, which will affect the product quality and the environment, and the equipment investment will be large and the cost will be high.

Contents of the invention

The invention provides a method for producing dispersant MF by adopting a new sulfonation process. The method has simple process, does not pollute the environment, and can also co-produce sodium sulfite during production, thereby maximizing resource utilization.

A method for producing dispersant MF and co-producing sodium sulfite, comprising: adding sulfuric acid with a concentration of more than 95% to the methylnaphthalene raw material; The optimum temperature is 50-100°C; after the sulfur trioxide is fully reacted, vacuumize at 135-155°C, and continue to react until the total acidity of the reaction system is 22%-27%, and 23%-25% is the optimum; the sulfur dioxide produced by the sulfonation reaction The gas is absorbed with lye to prepare sodium sulfite; add water to the solution after sulfonation reaction to adjust the condensation acidity to 14%-20%, the optimal value is 16%-18%, and add formaldehyde aqueous solution for condensation. The temperature of condensation reaction is generally 80-120°C , the pressure generally does not exceed 0.2Mpa; after the condensation is completed, add water to dilute, add alkali to adjust the pH value to neutral, and obtain an aqueous solution of methyl naphthalenesulfonic acid formaldehyde condensate, that is, the dispersant MF.

The main reaction formula for producing dispersant MF is as follows:

(1) Sulfonation

(2) Condensation:

(3) Neutralization:

The raw material of methylnaphthalene can be pure methylnaphthalene, but in order to reduce the production cost, industrial methylnaphthalene or wash oil is optimally used. The methylnaphthalene content of the industrial methylnaphthalene is more than 60%, and the methylnaphthalene content of the washing oil is more than 25%. When adopting industrial methyl naphthalene, the weight ratio industrial methyl naphthalene of each substance in the reaction: sulfuric acid: sulfur trioxide: formaldehyde=1: 0.3～0.45:0.3～0.45:0.12～0.24, preferred industrial methyl naphthalene: sulfuric acid: Sulfur trioxide: formaldehyde=1:0.35～0.40:0.35～0.40:0.15～0.20; when adopting wash oil, the weight ratio of each substance in the reaction wash oil: sulfuric acid: sulfur trioxide: formaldehyde=0.9:0.3～0.45: 0.3～0.45:0.12～0.24, preferably washing oil: sulfuric acid: sulfur trioxide: formaldehyde=0.9:0.35～0.40:0.35～0.40:0.15～0.20.

In the reaction process of the inventive method, after the first sulfonation reaction of methylnaphthalene, concentrated sulfuric acid and sulfur trioxide is sufficient, the sulfonation temperature is increased, and simultaneously by vacuum dehydration, the concentrated sulfuric acid can be relatively fully reacted, and the reaction After finishing, there is only a very small amount of sulfuric acid in the solution.

Sulfur dioxide gas produced by sulfonation is absorbed by alkali solution to pH 4-9, the optimal value is 5-7, then add alkali to adjust pH value to 11-13, then filter to remove impurities, evaporate and concentrate, and dry the obtained sodium sulfite The content can be above 96%.

Described lye and alkali optimally use sodium hydroxide, although sodium carbonate, sodium bicarbonate etc. can also be used, but can produce greenhouse gas carbon dioxide in the reaction process.

Compared with the conventional process, the process of the present invention does not need to use lime to neutralize, so solid wastes such as calcium sulfate will not be produced, and it has the advantage of low calcium and magnesium ion content. Since the residual free sulfuric acid is less, the content of sodium sulfate Generally below 5%, the quality can reach the Chinese quality standard GB9294-88. At the same time, sulfur dioxide waste gas has also been reasonably recycled, turning waste into treasure, featuring low energy consumption, and is a clean and environmentally friendly production process.

Detailed ways

Example 1

Put 60g of industrial methylnaphthalene into the reaction vessel, add 23g of 98% concentrated sulfuric acid, stir evenly, then slowly pass in about 25g of sulfur trioxide gas, control the reaction temperature at 50-60°C, and control the passage time at 1-2 Hours, pass through, heat preservation reaction for 1 hour, heat up to 150°C, vacuumize, control the vacuum degree at about 0.025Mpa, react at this temperature for 3 hours, then take samples to measure the acid value, after the acidity is qualified, cool down to 110°C, Add a certain amount of water to adjust the condensation acidity to 18%, then lower the temperature to 70°C and add 27g of formaldehyde solution (general concentration is 36% to 38%), heat up to 110°C and pressurize for 5 hours, then lower the temperature and pressure, add water to dilute , add sodium hydroxide to adjust the pH value to neutral, and obtain the aqueous solution of dispersant MF, and dry it to obtain solid powder MF.

The sulfur dioxide gas produced by sulfonation is absorbed with 15% sodium hydroxide solution until the pH value is 5.5, and sodium hydroxide is added to make the pH value of the absorbed lye 13, filtered to remove impurities, concentrated by evaporation, and dried to obtain a content of more than 96%. commercial sodium sulfite.

Example 2

Put 60g of washing oil into the reaction vessel, add 24g of 98% concentrated sulfuric acid, stir evenly, then slowly feed about 26g of sulfur trioxide gas, control the reaction temperature at 70-80°C, and control the feeding time at 2-3 hours, After passing through, keep warm for 1 hour, start to heat up to 140°C, vacuumize, control the vacuum degree at about 0.02Mpa, react at this temperature for 3 hours, then take samples to measure the acid value, after the acidity is qualified, cool down to 100°C, add certain Amount of water, adjust the condensation acidity to 20%, then lower the temperature to 70°C, add 26g of formaldehyde solution (general concentration is 36%~38%), raise the temperature to 110°C and pressurize for 5 hours, then lower the temperature and reduce the pressure, add water to dilute, add Adjust the pH value to neutral with sodium hydroxide to obtain the aqueous solution of dispersant MF, and dry it to obtain solid powder MF.

The sulfur dioxide gas produced by sulfonation is absorbed with 15% sodium hydroxide solution until the pH value is 7, and sodium hydroxide is added to make the pH value of the absorbed lye solution 11, filtered to remove impurities, concentrated by evaporation, and dried to obtain a content of more than 96%. commercial sodium sulfite.

Example 3

Put 60g of industrial methylnaphthalene into the reaction vessel, add 24g of 98% concentrated sulfuric acid, stir evenly, then slowly pass in about 24g of sulfur trioxide gas, control the reaction temperature at 80-90°C, and control the passage time at 2-3 Hours, pass through, heat preservation reaction for 1 hour, start to heat up to 145°C, vacuumize, control the vacuum degree at about 0.03Mpa, react at this temperature for 3 hours, then take samples to measure the acid value, after the acidity is qualified, cool down to 110°C, Add a certain amount of water to adjust the condensation acidity to 15%, then lower the temperature to 70°C and add 28g of formaldehyde solution (general concentration is 36% to 38%), heat up to 110°C and pressurize for 5 hours, then lower the temperature and pressure, add water to dilute , add sodium hydroxide to adjust the pH value to neutral, and obtain the aqueous solution of dispersant MF, and dry it to obtain solid powder MF.

The sulfur dioxide gas produced by sulfonation is absorbed with 15% sodium hydroxide solution until the pH value is 7.5, and sodium hydroxide is added to make the pH value of the absorbed lye 12, filtered to remove impurities, concentrated by evaporation, and dried to obtain a content of more than 96%. commercial sodium sulfite.

Claims (3)

1. method of producing Dispersant MF and coproduction S-WAT, comprise, in the methylnaphthalene raw material, add the sulfuric acid of concentration more than 98%, feed sulphur trioxide, 50～100 ℃ are carried out sulfonation reaction, after sulphur trioxide fully reacted, 135～155 ℃ vacuumized, continue to react to the total acidity of reaction system be 23%～25%; The sulfur dioxide gas body and function alkali lye that sulfonation reaction produces absorbs the preparation S-WAT; After solution after the sulfonation reaction adds water and is adjusted to condensation acidity 16%～18%, add formalin and carry out condensation, the condensation back thin up that finishes adds alkali and regulates pH value to neutrality, obtains Dispersant MF; Wherein said methylnaphthalene raw material is technical methylnaphthalene or washing oil, when described methylnaphthalene raw material is technical methylnaphthalene, the weight ratio technical methylnaphthalene of each material in the reaction: sulfuric acid: sulphur trioxide: formaldehyde=1: 0.35～0.40: 0.35～0.40: 0.15～0.20; When described methylnaphthalene raw material is washing oil, the weight ratio washing oil of each material in the reaction: sulfuric acid: sulphur trioxide: formaldehyde=0.9: 0.35～0.40: 0.35～0.40: 0.15～0.20.

2. the method for claim 1 is characterized in that: described sulfurous gas with alkali lye absorb to the pH value be 4～9 o'clock, add alkali and regulate pH value to 11～13, filtering and impurity removing then, evaporation concentration, drying obtains S-WAT.

3. method as claimed in claim 1 or 2 is characterized in that: described alkali lye is sodium hydroxide solution; Described alkali is sodium hydroxide.