CN102392255B - Preparation method of sodium polyacrylate dispersing imidazoline corrosion inhibitor - Google Patents

Abstract

The invention discloses a preparation method of a sodium polyacrylate dispersing imidazoline corrosion inhibitor. The method is characterized by comprising the following preparation steps: (1) neutralizing crylic acid with sodium hydroxide solution; (2) preparing the aqueous solution of potassium persulfate and n-dodecanethiol; (3) preparing sodium carbonate aqueous solution; (4) mixing the aqueous solutions obtained in the above three steps, and introducing nitrogen; (5) standing in a water bath at the temperature of 52-58DEG C for at least 5h; and (6) washing and drying a product to constant weight to obtain the sodium polyacrylate with low molecular weight. After about 20% of the sodium polyacrylate disclosed by the invention is added, water-soluble imidazoline quaternary ammonium salt can be effectively dispersed, and corrosion inhibition efficiency is improved.

Description

Preparation method of sodium polyacrylate dispersed imidazoline corrosion inhibitor

technical field

The present invention relates to a kind of preparation method of corrosion inhibitor, relate in particular to a kind of preparation method of low molecular weight sodium polyacrylate.

Background technique

At present, the solution to the hydrogen sulfide, carbon dioxide and chloride ion corrosion problems in the petroleum industry is to use corrosion inhibitors, and water-soluble imidazoline quaternary ammonium salts are currently one of the most effective corrosion inhibitors. However, to give full play to the corrosion inhibition function of imidazoline, it is necessary to fully disperse it.

The low-molecular-weight sodium polyacrylate prepared by the invention can effectively disperse the water-soluble imidazoline, so that the corrosion inhibition ability of the water-soluble imidazoline quaternary ammonium salt can be fully exerted, and the dosage is small, and the corrosion inhibition efficiency is high.

Contents of the invention

The object of the present invention is to provide a kind of corrosion inhibitor preparation method suitable for carbon steel and alloy steel, the sodium polyacrylate with molecular weight synthesized by this preparation method can effectively disperse water-soluble imidazoline quaternary ammonium salt at the molecular weight of 500～1000, is used for improving Corrosion inhibition ability of water-soluble imidazoline quaternary ammonium corrosion inhibitors.

The present invention is realized like this, it is characterized in that preparation method step is:

(1) Neutralize acrylic acid with 25% sodium hydroxide aqueous solution, and add water to adjust the mass fraction of acrylic acid to 25%;

(2) Prepare an aqueous solution with 6% n-dodecylmercaptan and 5% potassium persulfate by the mass of acrylic acid;

(3) Sodium carbonate with 20% molar weight of acrylic acid is prepared into an aqueous solution;

(4) Mix the aqueous solution prepared in steps (1), (2) and (3), put it into a flat plastic bag, and tie the mouth of the bag tightly after passing nitrogen gas for 10 minutes;

(5) Place in a water bath at 55±3°C for more than 5 hours;

(6) After washing the product, place it in a vacuum drying oven to constant weight to obtain sodium polyacrylate with a molecular weight of 500-1000.

(7) Prepare a 25% aqueous solution of sodium polyacrylate, and add it to a water-soluble imidazoline quaternary ammonium salt that is 5 times the mass of sodium polyacrylate to obtain a corrosion inhibitor.

The invention has the advantages that: in the water medium, the usage amount of the water-soluble imidazoline quaternary ammonium salt is 20 mg/L, and the corrosion inhibition efficiency for carbon steel and alloy steel reaches more than 99%.

Detailed ways

Embodiment one

(1) Dissolve 40 g of sodium hydroxide in 160 ml of water to prepare a 25% sodium hydroxide solution, neutralize 72 g of acrylic acid, and add 130 ml of water after neutralization;

(2) Dissolve 3.6 g of potassium persulfate and 4.3 g of n-dodecanethiol in water to prepare an aqueous solution;

(3) Dissolve 21 g of sodium carbonate in water to prepare an aqueous solution;

(4) Mix the aqueous solution prepared in steps (1), (2) and (3), put it into a flat plastic bag, and tie the mouth of the bag tightly after passing nitrogen gas for 10 minutes;

(5) Place in a water bath at 55±3°C for more than 5 hours;

(6) After washing the product, place it in a vacuum drying oven to constant weight to obtain sodium polyacrylate with a molecular weight of 500-1000.

Embodiment two

(1) Dissolve 80 g of sodium hydroxide in 320 ml of water to prepare a 25% sodium hydroxide solution, neutralize 144 g of acrylic acid, and add 260 ml of water after neutralization;

(2) Dissolve 7.2 g of potassium persulfate and 8.6 g of n-dodecanethiol in water to prepare an aqueous solution;

(3) Dissolve 42 g of sodium carbonate in water to prepare an aqueous solution;

(4) Mix the aqueous solution prepared in steps (1), (2) and (3), put it into a flat plastic bag, and tie the mouth of the bag tightly after passing nitrogen gas for 10 minutes;

(5) Place in a water bath at 55±3°C for more than 5 hours;

(6) After washing the product, place it in a vacuum drying oven to constant weight to obtain sodium polyacrylate with a molecular weight of 500-1000.

Embodiment three

(1) Dissolve 60 g of sodium hydroxide in 240 ml of water to prepare a 25% sodium hydroxide solution, neutralize 108 g of acrylic acid, and add 195 ml of water after neutralization;

(2) Dissolve 5.4 g of potassium persulfate and 6.5 g of n-dodecanethiol in water to prepare an aqueous solution;

(3) Dissolve 32 g of sodium carbonate in water to prepare an aqueous solution;

(4) Mix the aqueous solution prepared in steps (1), (2) and (3), put it into a flat plastic bag, and tie the mouth of the bag tightly after blowing nitrogen gas for 10 minutes;

(5) Place in a water bath at 55±3°C for more than 5 hours;

(6) After washing the product, place it in a vacuum drying oven to constant weight to obtain sodium polyacrylate with a molecular weight of 500-1000.

Claims (1)

1. a sodium polyacrylate disperses the preparation method of imidazolines inhibiter, it is characterized in that preparation method and step are:

(1) be in 25% the aqueous sodium hydroxide solution and vinylformic acid with massfraction, and adding water, to be adjusted to acrylic acid massfraction be 25%;

(2) being the positive Dodecyl Mercaptan of vinylformic acid quality 6% and 5% Potassium Persulphate, be mixed with the aqueous solution;

(3) the yellow soda ash that is vinylformic acid molar weight 20%, be mixed with the aqueous solution;

(4) after the aqueous solution of step (1), (2) and (3) being prepared, put into the platypelloid type plastics bag, tighten sack after passing into nitrogen 10 min;

(5) place more than 55 ± 3 ℃ water-bath 5 h;

(6) with after the product washing, place in the vacuum drying oven to constant weight, obtain molecular weight and be 500 ~ 1000 sodium polyacrylate;

(7) sodium polyacrylate is formulated as 25% the aqueous solution, is incorporated as in the 17 thiazolinyl sodium carboxymethyl type imidazoline quaternary ammonium salts of 5 times of sodium polyacrylate quality, obtain inhibiter.