CN103484091B - O-vanillin p-aminobenzoic acid Schiff-base polyethylene glycol monolaurate and application thereof - Google Patents

Abstract

The invention discloses a kind of tensio-active agent o-vanillin contracting acid Schiff-base polyethylene glycol monolaurate and the application thereof with corrosion inhibition, the structural formula of O-vanillin p-aminobenzoic acid Schiff-base polyethylene glycol monolaurate is:

Description

O-vanillin acetal p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester and its application

technical field

The invention belongs to the technical field of corrosion inhibitors, and in particular relates to o-vanillin p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester which prevents carbon steel and its products from corroding in oil field aqueous solution.

Background technique

Metal materials are widely used in various fields. Corrosion of metal materials will cause huge losses to the economy of the country. According to relevant reports, the annual economic losses caused by metal corrosion in industrialized countries account for 2% of the gross national product of the year. -4%. Therefore, the research and development of metal corrosion protection methods is of great significance to promote social and economic development. The application of surfactants in the field of metal corrosion inhibition is one of its most important applications. Surfactants with corrosion-inhibiting properties can form an adsorption film on the metal surface, and hydrophilic groups are adsorbed on the metal surface to undergo physical or chemical adsorption, forming a geometric coverage effect, thereby inhibiting the corrosion of the metal. In recent years, the development and application of surfactants has always been a hot spot in the chemical and corrosion inhibition circles, and some new types of surfactants have emerged, such as Gemini Surfactants, ionic liquid surfactants, etc. , new oligomeric surfactants and new Schiff base surfactants, etc. These surfactants have surface activity and have also made great contributions to metal corrosion inhibition. Looking at previous research results, most of them simply use the amphiphilic structure of surfactants to achieve the purpose of corrosion inhibition. Since Schiff base compounds contain imine groups (-C=N-), some aromatic Schiff bases contain -C=N-double bonds, and some benzene rings also have -OH groups, and organic Corrosion inhibitor molecules contain heteroatoms such as N, S, O or P and π-electron conjugated systems, which are easy to form coordination bonds with metals, so that they can be adsorbed on the metal surface to form a corrosion-inhibiting protective film. Therefore, if the Schiff base structure can be introduced into the surfactant molecule, the application range of the surfactant is expected to be expanded and the corrosion inhibition performance is expected to be improved. Based on the above thinking, the present invention condenses the Schiff base structure with polyethylene glycol laurate monoester long chain, and synthesizes o-vanillin p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester surfactant, The corrosion inhibition effect of this new surfactant on carbon steel in simulated oilfield water was also explored.

Contents of the invention

The object of the present invention is to provide a kind of surfactant o-vanillin acetal p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester with corrosion inhibiting effect and application thereof.

The structural formula of o-vanillin p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester is:

.

The o-vanillin p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester is applied to prevent corrosion of carbon steel and its products in oil field aqueous solution.

The advantage of the present invention is that by virtue of the surface activity of the surfactant and the Schiff base coordination function, the o-vanillin acetal p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester is easy to adsorb and form a film on the surface of carbon steel , with high corrosion inhibition performance.

Detailed ways

Example:

(1) The structural formula of o-vanillin p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester:

.

(2) The preparation method of o-vanillin p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester is:

a. Preparation of o-vanillin p-aminobenzoic acid Schiff base

Take by weighing 1.5214 grams (0.01 mole) of o-vanillin and place it in a 100 milliliter three-necked flask, dissolve it ultrasonically with 30 milliliters of absolute ethanol, weigh 1.3714 grams (0.01 mole) of p-aminobenzoic acid in an equimolar amount in a beaker, and use 40 Ultrasonic dissolution in one milliliter of absolute ethanol, the above two solutions were mixed in a constant temperature water bath at 65°C, then magnetically stirred and refluxed for 2 hours, the product was taken out and left to stand for 7 hours, filtered after all the precipitates were precipitated, and the filtrate was washed twice with absolute ethanol , placed in a vacuum drying oven at 40°C for 24 hours to obtain an orange-yellow solid that is o-vanillin p-aminobenzoic acid Schiff base.

b. Preparation of polyethylene glycol laurate monoester

Weigh 12 grams (0.03 moles) of polyethylene glycol (400) and 0.6183 grams (0.01 moles) of boric acid and place them in a 100 ml three-necked flask. Heat to 120°C, continue to react for 2 hours, after cooling to room temperature, add 6.0096 grams (0.03 moles) of lauric acid and 0.226 grams of p-toluenesulfonic acid, and continue heating to 120°C in an oil bath under a low pressure of 0.1MPa. Continue to react for 3 hours, cool to room temperature, then add 0.7 g of sodium acetate to neutralize p-toluenesulfonic acid in the system, then add 5 ml of distilled water, stir in a water bath at 95°C, perform selective hydrolysis for 1 hour, and then add an equal volume of Saturated saline, dissolve sodium p-toluenesulfonate, unreacted sodium acetate and sodium borate generated after hydrolysis in saturated brine, and after cooling, separate the product solidified in the upper layer, and separate the product in a rotary evaporator Rotate slowly in the instrument to remove water, and obtain a light yellow oily liquid which is polyethylene glycol laurate monoester.

c. Preparation of o-vanillin p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester

Weigh 2 mmoles of o-vanillin p-aminobenzoic acid Schiff base prepared in step a and 2 mmoles of polyethylene glycol laurate monoester obtained in step b and dissolve in 20 milliliters of N,N-di In the methyl formamide solvent, after mixing evenly, add 0.0196 g of p-toluenesulfonic acid as a catalyst, heat the oil bath to 130°C, and continue the reaction for 3 hours. After cooling, evaporate the solvent to obtain a wine-red oily liquid that is o-vanillin Condensed p-aminobenzoic acid Schiff base polyethylene glycol monolaurate.

(3) Application of o-vanillin p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester:

a. Prepare carbon steel test pieces: Prepare 16 carbon steel pieces with a specification of 50 mm × 10 mm × 2 mm, use 240#, 600# and 1500# water-grinding paper to polish the carbon steel sheets until smooth, put them in Soak in a beaker filled with acetone for 5 minutes, dry it with absorbent cotton, then soak it in absolute ethanol for 5 minutes for further degreasing, take out the test piece and blow it dry with a hair dryer, dry it in a drying box for 5 hours, take it out and use it for analysis The balance is accurately weighed to 0.0001 gram, and the data is recorded, and the unused section is sealed with solid paraffin, and a 1×1 square centimeter working surface is reserved for future use.

b. Preparation of simulated oilfield water: weigh the medicine according to the formula in Table 1 and add distilled water to stir until completely dissolved, transfer it to a 1-liter volumetric flask for constant volume, pass nitrogen for 15 minutes to remove oxygen, and then pass carbon dioxide to saturation to obtain simulated oilfield water.

Table 1 Simulated oilfield water formula

c. Determination of corrosion inhibition performance by weight loss method: take 20 ml each of the simulated oilfield water prepared in step b and fill them in 6 50 ml beakers of the same size and specification, one of which is the blank control group, and the other 5 groups are respectively added with different The quality of o-vanillin p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester, so that the concentration of o-vanillin p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester in simulated oilfield water 20 mg/L, 50 mg/L, 100 mg/L, 150 mg/L, and 200 mg/L respectively, and then mark the carbon steel sheets treated in step a and put them into 6 beakers for weight loss test The period is 72 hours, and the beaker needs to be sealed during the experiment; after 72 hours, take out the carbon steel sheet to remove the solid paraffin on the surface, rinse it with distilled water, gently wipe off the corrosion products on the surface with absorbent cotton, put it in petroleum ether to degrease and remove oil, Wipe it with absorbent cotton and then ultrasonically clean it with absolute ethanol for 5 minutes to further degrease. Finally, dry it with filter paper and put it in a drying oven for 4 hours. times, take the average value.

The corrosion rate V is calculated according to formula (1), and the corrosion inhibition efficiency IE is calculated according to formula (2):

V=(W ₀ -W _t )/(S×t) (1)

In the formula, V is the corrosion rate, g·m ^-2 ·h ^-1 ; W ₀ and W _t are the mass of the carbon steel test piece before and after corrosion respectively, g; S is the working area of the test piece, m ² ; t is the corrosion test time, h.

IE=[(V ₀ –V _t )/V ₀ ]×100% (2)

In the formula, IE is the corrosion inhibition efficiency, %; V ₀ is the corrosion rate under blank condition, g·m ^-2 ·h ^-1 ; V _t is the corrosion rate under the condition of adding corrosion inhibitor.

Table 2 Weight loss experiment data

From the weight loss experimental data in Table 2, it can be seen that the weight loss is significantly reduced after adding o-vanillin to shrink p-aminobenzoic acid Schiff base polyethylene glycol laurate monoester, indicating that o-vanillin shrinks p-aminobenzoic acid Schiff base poly Ethylene glycol monolaurate has good corrosion inhibition performance. When the concentration is 20 mg/L, the corrosion inhibition rate can reach more than 65%, and when the concentration is 50 mg/L, the corrosion inhibition rate can reach more than 80%. As the concentration continues to increase, when the concentration is 100 mg/L, the corrosion inhibition rate reaches more than 82%. As the concentration continues to increase, the corrosion inhibition rate does not change much, indicating that at 100 mg/L, The corrosion inhibitor molecules have been better adsorbed on the metal surface to form a relatively dense protective film.

Claims (2)

1. an O-vanillin p-aminobenzoic acid Schiff-base polyethylene glycol monolaurate, is characterized in that the structural formula of O-vanillin p-aminobenzoic acid Schiff-base polyethylene glycol monolaurate is:

；

Wherein repeating unit [CH ₂cH ₂o] _nbe consistent with the repeating unit in poly(oxyethylene glycol) 400.

2. the application of O-vanillin p-aminobenzoic acid Schiff-base polyethylene glycol monolaurate according to claim 1, is characterized in that described O-vanillin p-aminobenzoic acid Schiff-base polyethylene glycol monolaurate is applied to and prevents carbon steel and goods thereof from corroding in oil-field water solution.