WO2012094816A1

WO2012094816A1 - Phosphorous-free corrosion and scale inhibitor and synthesis thereof

Info

Publication number: WO2012094816A1
Application number: PCT/CN2011/070252
Authority: WO
Inventors: 王锦堂; 徐斌
Original assignee: 南京工业大学
Priority date: 2011-01-14
Filing date: 2011-01-14
Publication date: 2012-07-19

Abstract

Phosphorus-free corrosion and scale inhibitor and synthesis are provided. The following structure of the inhibitor is shown in (I), among which n is between 2 and 100. The inhibitor has the functional groups such as carboxylic, polyepoxysuccinic and dithiocarbamate etc.. Said functional groups have synergistic effect which make better scale and dispersion properties. The inhibitor is phosphorus-free and biodegradable which is favorable for environment protection. The raw materials of the product are easy to obtain. Relatively low in production cost or in price.

Description

Instruction manual

Phosphorus-free corrosion and scale inhibitor and synthesis method thereof

Technical field

The invention belongs to the technical field of industrial circulating cooling water treatment, and particularly relates to a novel multifunctional corrosion and scale inhibitor and a preparation method thereof. Background technique

With the development of modern industry and the increasing requirements for environmental protection, higher requirements have been placed on industrial circulating cooling hydration chemicals. It is suitable for the preparation of water treatment agents with various functions such as scale inhibition, corrosion inhibition, dispersion and sterilization in a wide water quality range, and its mechanism of action is the main content of current water treatment agent research. The development of organic compounds containing multiple functional groups in one molecule has become a research hotspot.

Current scale inhibitor research focuses on organic polyphosphate scale inhibitors and polycarboxylic acid scale inhibitors. Corrosion inhibitors are mainly concentrated in organic phosphorus, organic amines and compound corrosion inhibitors. These phosphine-based all-organic formulations of a compound having a plurality of functional groups such as a carboxylic acid, a sulfonic acid, and a phosphonic acid have been widely recognized for their excellent corrosion and scale inhibition properties, and have been considered to be green because of their greatly reduced phosphorus content. Corrosion and scale inhibitor. However, the phosphine-based all-organic formula is also a phosphorus-containing corrosion and scale inhibitor. Although the organic phosphonic acid is stable and difficult to be naturally hydrolyzed, due to the complexity of the water itself, orthophosphate is still produced during use, and the water body is rich in nutrients. Trends. With the strengthening of environmental protection and water-saving awareness, the concept of “green scale inhibitor” has been continuously proposed, making the development of low-phosphorus and even phosphorus-free multifunctional water treatment agents increasingly important.

The successful development of polycarboxylate water treatments such as polyacrylic acid and polymaleic acid is a breakthrough in water treatment technology, which has been considered an environmentally acceptable scale inhibitor due to the absence of phosphorus. However, studies have shown that its biodegradability is poor, and its long-term accumulation in the environment is potentially harmful.

With the development of phosphorus-free, biodegradable corrosion and scale inhibitors polyepoxysuccinic acid and polyaspartic acid, the concept of "green corrosion and scale inhibitor" has become the development direction of water treatment agents in this century. However, U.S. Patent No. 5,147,555 also shows that polyepoxysuccinic acid has good corrosion inhibition properties and carbon inhibition. Calcium acid and calcium sulfate have poor scale inhibition effect on calcium phosphate.

Studies have shown that the ammonia sulphate formed by the reaction of 8 ₂ with an organic amine (primary or secondary amine) under alkaline conditions, also known as dithiocarbamate, referred to as DTC, has excellent sterilization and resistance. It has become a broad-spectrum oilfield chemical agent because of its scale and corrosion inhibition properties and its good biodegradability. It has played a role in the sewage treatment, corrosion inhibition, acidification and sterilization of oil fields. Patent SPE26008 (1993) reports the use of DTC water purifying agents in the production water treatment systems of the Gulf of Mexico and the North Sea oil field. Patent US516409 Patent 1 ^ 565,848 and reported to ⁰¹¹ (for the removal of heavy metal ions in sewage eight _§, Hg, Pb, etc. SUMMARY

The object of the present invention is to enrich and develop an environmentally friendly industrial circulating water treatment agent in accordance with the development direction of modern water treatment agent technology, and provide an aspartic acid-free phosphorus-free water treatment agent, which is a carboxylic acid and an ammonia acid. And groups such as polyepoxysuccinic acid are introduced into the multi-functional water treatment agent for corrosion inhibition and scale inhibition treatment of water quality, in order to obtain a "green corrosion and scale inhibitor" with better performance.

Another object of the present invention is to provide a process for the preparation of the above compounds.

The object of the invention can be achieved by the following measures:

A novel phosphorus-free, biodegradable green corrosion and scale inhibitor having a corrosion inhibition scale inhibitor having the following formula (I):

11 is 2 to 100, preferably 3 to 80, and most preferably 3 to 60.

The preparation method of the above phosphorus-free corrosion and scale inhibitor having the structure of the formula (I), the specific steps include: dissolving monomethyl maleate in a solvent, then adding to ethylenediamine to heat the reaction, cooling after the reaction, adding The ethanol solution of carbon disulfide is further reacted. After completion of the reaction, an aqueous solution of sodium epoxysuccinate is added to adjust the pH to 10.0 to 12.0, and then Ca(OH) _{2 is} added to heat the reaction.

The solvent is water or/and ethanol. Monomethyl maleate is heated to reflux under ethylenediamine, After the reaction, the temperature was lowered to 10 ° C or lower; the reaction temperature after the addition of the carbon disulfide in ethanol solution was 10 ° C or less; and the reaction was carried out by adding & (011) ₂ and heating to 80 to 100 ° C. The amount of each reactant is determined by the structure of the target compound and the specific reaction process, and the purpose of complete reaction is as much as possible. For polymers of the formula I structure, where n is not a determined number, but the average of all high molecular weight polymers produced.

The present invention also includes a corrosion and scale inhibiting composition comprising the above-described phosphorus-free corrosion and scale inhibitor having the structure of the formula (I) as an active ingredient, supplemented by an auxiliary material commonly used in the field of corrosion and scale inhibition. The amount of the active ingredient to be used in the composition can be adjusted as the case may be, for example, it can be adjusted in the range of 10 to 90%.

The present invention uses biodegradable aspartic acid as a basic structural skeleton, and a group such as ammonia acid and polyepoxysuccinic acid is introduced therein. Since polyepoxysuccinic acid itself is a good scale inhibitor and dispersant, aspartic acid has been proven to be a good environmentally friendly water treatment agent. The strong supply of sulfur in the ammonia acid group can be adsorbed on the surface of the crystal. At the growth point, it is distorted and inhibits the growth of the crystal lattice in a certain direction, so that the lattice distortion is not long, and the three synergistically achieve the scale inhibition effect. At the same time, the electron-donating lysine group is adsorbed on the metal surface. On the one hand, changing the charge state and interface properties of the metal surface, the energy state of the metal surface tends to be stabilized, thereby increasing the activation energy (energy barrier) of the corrosion reaction and slowing down the corrosion rate; on the other hand, the adsorbed corrosion inhibitor The non-polar groups form a hydrophobic protective film on the surface of the metal, which hinders the transfer of charge or matter associated with the corrosion reaction (movement barrier) and thus reduces the rate of corrosion.

The main advantage of the present invention is that the product is phosphorus-free and contains various functional groups such as a carboxylic acid group, a polyepoxysuccinic acid group and an ammonia acid salt. These functional groups are active functional groups of current water treatment agents, and the compounds concentrate these functional groups. Integral, using the synergy between them, it has better scale inhibition and dispersing properties; at the same time, the product is phosphorus-free, biodegradable and beneficial to the environment; and the raw materials of this product are simple and easy to obtain, and the production cost is low. The price is low, easy to be accepted by customers, and easy to promote. Therefore, this product is a new type of water treatment agent, which is a new generation of water treatment agents such as organic phosphonic acid and sulfonic acid, which can be used in industrial circulating cooling water treatment in petrochemical, chemical, metallurgical, electric power and other industries. Widely used, with very good prospects for promotion and application. detailed description

Example 1:

Preparation 26 g (0.2 mol) of monomethyl maleate was dissolved in a solvent (water and ethanol), and then added dropwise to 6 g (0.1 mol) of ethylenediamine, heated to reflux for 2 to 3 h, and cooled to below 10 ° C. Ethanol solution of carbon disulfide was added dropwise (6 mL + 15 mL control temperature not higher than 10 ° C, reaction 2~4 h, and the obtained orange liquid was further added with 176 g of sodium epoxysuccinate aqueous solution (mass concentration 30%, containing epoxy succinic acid 0.3) Mol), adjust the pH to 11.0, add C«(OH) ₂ 0.3g, heat to 90 ° C for 3 hr and then cool down, finally to obtain orange-yellow viscous liquid; solid content ^ 30%.

Example 2:

The preparation was the same as in Example 1, except that the amount of the aqueous solution of epoxysuccinic acid was 1,760 g.

Example 3:

Preparation Spectral analysis and characterization, the results are shown in Table 1:

Table 1

IR/cm- ¹ belongs to

3412 0-H stretching vibration

2973, 2870 -CH ₃ , -CH ₂ - stretching vibration

1606 c=s stretching vibration

1584, 1418 carboxylate symmetry and asymmetric vibration

1396, 1312 C-0 telescopic vibration

1204 C-N stretching vibration

1111, 1070 C-0-C asymmetric stretching vibration

The solid product was subjected to saponification, and the saponification values of Examples 1 to 3 were as follows: 110. 9, 19. 5 and 10.1. Where: corrected saponification value = saponification value - base number

Scale inhibition of calcium phosphate scale

experiment method

(1) Weigh lg sodium tetraborate dissolved in deionized water, transfer to a 1000mL volumetric flask, add deionized water 900mL, and then pipet 1.00mL PO ₄ ³ — (5.00 g / L) stock solution into it, to volume Shake well, P0 ₄ ^{3 in} this solution - the concentration is 5.00mg / L, now used.

(2) Add a certain amount of scale inhibitor stock solution to the 50mL volumetric flask, add 40mL of the solution in (1), and slowly add 5.00mL of calcium ion stock solution (25mg/mL calculated as CaC0 ₃ ) diluted 10 times. Make up to volume with the solution in (1) and shake well.

(3) Place the above solution in an oven at 50 °C, slowly raise the temperature to 80 °C and start timing. After standing at a constant temperature for 10 hours, remove it, cool it, add deionized water to the mark, shake well, filter after cooling, analyze P0 ₄ ³ — concentration and determination of pH.

(4) The blank reagents with the same steps without the scale inhibitor should be carried out simultaneously in the test.

(5) The concentration of orthophosphorus is determined by phosphorus molybdenum spectrophotometry.

(6) Calculate the scale inhibition rate according to the scale inhibition rate formula.

[P0 ₄ 1o: PO ₄ ³ concentration measured before the test solution test

[Ρ0 ₄ ΐ! : The concentration of the test solution with the scale inhibitor added after the test ΡΟ ₄ ³ - concentration

[Ρ0 ₄ -] ₂ :: Ρ0 ₄ ³ concentration remaining after the same test without the scale inhibitor

Comparison of calcium phosphate scale performance

Agent concentration

5 10 20

Pharmacy ^\

Example 1 scale inhibition rate (%) 33.1 58.5 86.8

Example 2 scale inhibition rate (%) 32.7 57.7 91.2

Example 3 scale inhibition rate (%) 39.9 51.2 81.9

Scale inhibition rate of HEDP (%) 17.4 18.7 22.4

Scale inhibition rate of HPMA (%) 24.2 30.0 35.2

Experimental conditions: CCa2+=250mg/L, CP0 ₄ ³ =5mg/L, pH=9.0, T=80°C, t=10h, through polarization curve study and investigation of corrosion inhibition effect experimental method

1. Electrode fabrication and surface treatment methods

The working electrode is made of carbon steel and copper, the working area of the electrode is 0.2042 cm ² , and the rest is sealed with epoxy resin. Before the test, the electrodes were polished to 600°, 800*, 1000*, 1200*, 1500# metallographic sandpaper in order to be mirror-like, and the cotton was wiped with absorbent cotton to remove oil stains.

2. Experimental setup and steps

The electrolytic cell uses a three-electrode system, the saturated calomel electrode is the reference electrode, and the platinum electrode is the auxiliary electrode. The electrolyte solution was 1 M HCl and was prepared in laboratory distilled water. Insert the prepared electrode into the electrolyte solution (1M HC1) and connect the circuit. If the solution needs to be deoxidized, connect the deaerator, first deoxidize the solution (high purity nitrogen) for 15 minutes and then insert the electrode, continue to pass nitrogen until the end of the experiment. After the circuit is connected, first activate the electrode with a small current of the cathode for 2 minutes to remove the oxide film on the surface of the electrode, and then After the potential is stabilized, the polarization curve is measured, and the potential step rate is 60 mV/min.

Experimental results: The compound of the invention has obvious corrosion inhibition effect in the hydrochloric acid system, and the inhibition rate reaches about 90% when the concentration reaches lmmol/L. The inhibitor of the cathode is more effective in suppressing the corrosion current of the cathode, and the effect of the concentration on the corrosion inhibition effect is relatively small.

Claims

Claim

1. A phosphorus-free corrosion and scale inhibitor having the formula (I),

11 is 2~100.

The phosphorus-free corrosion and scale inhibitor according to claim 1, wherein n is from 3 to 80.

The phosphorus-free corrosion and scale inhibitor according to claim 2, wherein n is from 3 to 60.

A method for preparing a phosphorus-free corrosion and scale inhibitor having the structure of the formula (I) according to claim 1, wherein: the monomethyl maleate is dissolved in a solvent and then added to ethylenediamine for heating. The reaction was cooled, and the reaction was carried out by adding a solution of carbon disulfide in ethanol. After completion of the reaction, an aqueous solution of sodium succinate was added to adjust the pH to 10.0 to 12.0, and then Ca(OH) ₂ was added thereto to heat the reaction.

The method according to claim 4, wherein the solvent is water or/and ethanol.

6. The preparation method according to claim 4, wherein: the monomethyl maleate is heated to reflux under ethylenediamine, and the reaction is cooled to below 10 ° C; and the reaction after adding carbon disulfide in ethanol solution. The temperature is below 10 ° C; the reaction is carried out by adding Ca(OH) ₂ and heating to 80 to 100 ° C.

A corrosion and scale inhibiting composition characterized by comprising the phosphorus-free corrosion and scale inhibitor having the structure of the formula (I) according to claim 1 as an active ingredient.