JPS5924189B2 - Polybasic acid salt type rust inhibitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rust inhibitor comprising a novel polybasic acid salt compound, and more specifically, the present invention relates to a rust preventive agent having the general formula CH3 (
CH2)nCH-CH-CH-CH-(CH2)n'C
OOZlIl1ZDOCXCOOZCOOZ (wherein n and n' are numbers from 4 to 10, Or ammonium ion.

), it relates to a rust inhibitor consisting of a sodium, potassium, lithium or ammonium salt of a tetra or pentacarboxylic acid.

Conventionally, various rust preventives have been proposed, but
There are few low-toxicity compounds that can be used over a wide range of applications, and there are almost no known ones that can simultaneously prevent the rust of many types of metals.

For example, this type of rust inhibitor includes oil-soluble ones such as petroleum sulfonates, sorbitan monooleate, metal soaps, etc., and water-soluble ones such as chromates, phosphates, and nitrites. water- and oil-soluble ones such as ethanolamine, benzotriazole, alkyl phosphate surfactants, long-chain quaternary ammonium halides, and higher amine salts, but these salts have limited solubility in specific solvents. Increasingly, they are effective only for certain metals, such as chromates, which cause pollution and are no longer usable. Furthermore, even if they are mixed, it is not always possible to obtain a rust preventive agent that combines the advantages of both components; they may not dissolve each other, or the disadvantages of each component may appear, or the sustainability of the effect may be lost. In addition, nitrites can react with lower amines to form carcinogenic nitrosamines.
The present inventors have so far studied methods for producing tetra- or pentacarboxylic acids and their esters, but
As a result of continued research into the applications of these salts, we found that they not only have practical advantages such as low toxicity and stability, but also
It was discovered that it has an excellent antirust ability against various metals, and based on this knowledge, the present invention was accomplished.

The salt of the tetra or pentacarboxylic acid represented by the general formula (I), which is an active ingredient of the rust preventive agent of the present invention, is produced by neutralizing or saponifying the acid or ester of the following general formula () by a conventional method. be able to.

Examples of the alkali used for neutralization include sodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonia. (In the formula, n and n' are numbers from 4 to 10, Y is a hydrogen atom or COOR.R and R' are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, respectively.

) In the production of this tetra- or pentacarboxylic acid salt, it goes without saying that esterification can be carried out as appropriate to convert the carboxyl group at a desired position into an ester group.

Conventionally, well-known polycarboxylic acids or esters include tricarboxylic acids having three carboxyl groups and tetracarboxylic acids having four carboxyl groups in their molecules, and some of these carboxyl groups are esters. There are polycarboxylic acid esters.

However, these polycarboxylic acids and their ester derivatives generally have short molecular chains, or have a basic structure with one or two carboxyl groups or ester groups at both ends of the molecular chain, that is, at the α and ω positions. Many of them were thought to be derivatives of straight-chain dicarboxylic acids.

Tetra or pentacarboxylic acid and tetra or pentacarboxylic acid di- or triester represented by the general formula () have one carboxyl group or ester group at one end of the molecular chain, that is, the α-position carbon, and one carboxyl group or ester group at the other end. is an alkyl group, and the other carboxyl group or ester group is a polycarboxylic acid or polycarboxylic acid ester bonded to the intermediate carbon of the molecular chain.

Therefore, these are novel polycarboxylic acids and polycarboxylic acid esters that are considered to be derivatives of ordinary linear monobasic acids. These tetra- or pentacarboxylic acids and tetra- or pentacarboxylic acid di- or triesters are produced from fatty acid derivatives having a cyclohexene ring as raw materials by ozonation and oxygen oxidation. The rust preventive agent of the present invention can be applied to various uses by preparing a salt of a tetra or pentacarboxylic acid represented by the general formula (1) as an aqueous solution, and usually has a concentration of 0.0005 to 3.
0 weight? Preferably 0.05 to 1.5 weight? It is used as an aqueous solution.

In the present invention, 3 of Z in the compound of general formula (1)
or more are Alwari metal or ammonium ions. When the proportion of alkali metal or ammonium ions in Z is decreased and the proportion of alkyl groups is increased, an oil-soluble rust inhibitor with a relatively low pH can be obtained. The rust preventive agent of the present invention has low toxicity, stability, and excellent rust preventive effect.

In particular, it exhibits an excellent rust-preventing effect on many metals such as soft iron, steel, aluminum, brass, copper, lead, tinplate, galvanized iron, and solder. It goes without saying that the rust preventive agent of the present invention can be used not only alone, but also in combination with other known rust preventive agents as appropriate. Next, the present invention will be explained in more detail based on Examples and Reference Examples.

The tetra- or pentacarboxylic acid esters used in the Examples were prepared according to Reference Examples 1 to 5 below, and the rust-preventive power test method was as explained below.

In addition, the raw materials used in the reference examples are fatty acid derivatives having a cyclohexene ring with the structures of the following general formulas A and B, and N, n/, R, R', etc. in the formulas are respectively used in the description of the reference examples. show.

Reference example 1 Raw material B (n-5, n'-7, R, Y (both CH3)3
．． 019 and 30 ml of glacial acetic acid were each weighed into a 50 ml pear-shaped three-way flask.

The flask was equipped with a gas blowing tube, a condenser, and a stirrer. For the reaction, place the flask in a constant temperature bath at 10-14°C, stir the solution, and add a mixed gas of ozone and oxygen (ozone concentration approximately 3w).
t%) was blown into the solution for 38 minutes to effect ozonation. After ozonation, manganese acetate (Mn(CH3CO2)2.4H20)
Add 0.029 of
m1/min) to perform decomposition and oxidation of ozonide. After the reaction, the reaction solution was filtered to remove the manganese compound, and then the acetic acid was distilled off, and the reaction product was collected with ether and washed with water.
The ether was distilled off to give the reaction product 3.189 (yield 90.3
%) was obtained.

This reaction product gave the following analytical values. That is, acid value: 244.6 (theoretical value: 252.4), IR spectrum (CrIL-1): 2500-2700 (carboxyl group), 1710 (carbonyl group), 11F {SJMR spectrum (Ppm): 0.9 (terminal methyl group), 1.2
-1.3 (methylene group), 3.4 (methyl ester group)
, 8.5-8.6 (carboxyl group), 13CNMR spectrum (Ppm): 14.3 (terminal methyl group), 23
．． 0 to 35.5 (methylene group), 40 (methyl ester group), 174.2 to 181.1 (carboxyl group). From these analysis results, it was confirmed that the reaction product was tetracarboxylic acid dimethyl ester having the following structure.
Reference Example 2 10.03 g of raw material A (n=5, n'-7, R, R/both CH3) and 80 ml of glacial acetic acid were each weighed into a 100 ml pear-shaped three-sided flask.

The flask was equipped with a gas blowing tube, a condenser, and a stirrer. For the reaction, the flask was placed in a constant temperature bath at 10 to 13° C., and while stirring the solution, a mixed gas of ozone and oxygen (ozone concentration: about 3.5 wt%) was blown into the solution at a flow rate of 210 ml/min for 80 minutes to effect ozonation.

After ozonation, acetic acid ester [Mn(CH3CO2)2.
4H20] was added thereto, and the temperature of the reaction solution was raised to 8'C while stirring, and at 8'C, oxygen gas (flow rate 210 ml/min) was blown in for 3 hours to perform oxidative decomposition of ozonide. After the reaction, the reaction solution was filtered to remove the manganese compound, then the acetic acid was distilled off, and the reaction product was extracted with ether and washed with water to obtain 10.33 g of the reaction product. Various analyzes were conducted on this reaction product and the following results were obtained. Neutralization value: 218.8 (theoretical value 223.3), IR vector (CrrL-1): 2500-2700 (carboxyl group), 1710 (carbonyl group), 1H NMR spectrum (Ppm): 0.88 (terminal methyl base), 1.3(
methylene group), 3.65 (methyl ester group), 8.0
8 (carboxyl group), 13CNMR spectrum (Pp
m): 14.0 (terminal methyl group), 22.4-34.1
(methylene group), 51.5-52.0 (methyl ester group), 171.8-178.4 (carbonyl group) From these analysis results, the reaction product is pentacarboxylic acid trimethyl ester with the following structure. It was confirmed.

~NoV (Shima 1j Reference Example 3 3.0 g of tetracarboxylic acid dimethyl ester obtained in Reference Example 1 was dissolved in 50 ml of ethanol, 50 ml of 2% aqueous solution of sodium hydroxide was added thereto, and the mixture was heated at 80 to 85°C.
The mixture was allowed to react for 2 hours.

After the reaction, the solution was concentrated by evaporation, 5 to 10 ml of water was added thereto, the total volume was made up to about 200 ml with methanol, and the precipitated inorganic salt was filtered off. Next, about 50 ml of ether was added to the filtrate, and the precipitated soap was filtered off. The obtained soap was purified by reprecipitation several times with a mixed solution of water/methanol/ether (1:20:5) to obtain 2.4 g of white crystals.
The spectral data of this product is shown below. IR spectrum ((7L-1): 1570 (carboxilade ion) 1H-NMR spectrum (δ): 1.30 (terminal methino(c), 1.70 (methylene) 13C-NMR spectrum (Ppm): 14.3 (terminal methyl), 22.6
~38.6 (methylene), 52.0 (methine), 167
．． 5 to 185,0 (carbonyl), and from these analysis results, the reaction product is tetrasodium 1,9,10,12-octadecanetetracarboxylate l) (hereinafter abbreviated as 0d4Na)
It was confirmed that

Reference Example 4 3.67 g of pentacarboxylic acid trimethyl ester obtained in Reference Example 2 was dissolved in 50 ml of ethanol, 70 ml of a 2% aqueous solution of sodium hydroxide was added thereto, and 80-8
The reaction was carried out at 5°C for 2 hours.

After the reaction, the reaction solution was evaporated and concentrated, 5 to 10 ml of water was added thereto, the total volume was made up to about 200 ml with methanol, and the precipitated inorganic salt was filtered off. Next, about 50 d of ether was added to the filtrate, and the precipitated liquid was filtered off. The obtained soap was purified by reprecipitation several times with a mixed solution of water/methanol/ether (1:20:5) to obtain 3.8 g of white crystals. The spectral data of this product is shown below. IR spectrum (c!n-1): 1570 (carboxilade ion) 1H-NMR spectrum (δ): 1.32 (terminal methyl), 1.70 (methylene) 13C-NMR spectrum (Ppm): 14,5 ( terminal methyl), 22.6-38
．． 5 (methylene), 51.7 (methine), 167.7~
184.7 (Carbonyl) These analysis results confirmed that the reaction product was pentasodium (IV) 1,9,10,11,12-octadecanepentacarboxylate (0d5Na).

Reference Example 5 Dissolve 3.0 g of tetracarboxylic acid in 50 ml of ethanol, add 52 ml of 2% aqueous sodium hydroxide solution with stirring, then attach a reflux condenser and gently boil the solution on a water bath. Ta.

When reacted in this state for 1 hour, it was found that even raw materials in which part of the raw material was an acid anhydride were converted into solids.
Next, bring the temperature to room temperature, add ethanol, and reduce the total volume of the solution to about 2
00ml, and about 50ml of ether was gradually added to precipitate Setsuken. After standing overnight, the precipitated Setsuken was filtered out. Furthermore, this filtrate is evaporated and concentrated to 5 to 10 m
Dissolve 1 in water and add ethanol to make a total volume of about 100ml
Then, by adding about 30 ml of ether, it was possible to further precipitate Setsuken. Combine both ingredients and mix with water/ethanol/ether (1:20).
:5) The mixed solution was purified by reprecipitation several times to obtain 3.15 g of tetracarboxylic acid tetrasodium salt as white crystals. The spectrum of this product completely matched that of Setsuken (self) shown in Example 1.

Test method for rust prevention ability 1) Pour 4 ml of sample aqueous solution into a test tube with a lid (φ10 x 70 mm), and add 4 to 10 types of test metal pieces (3 x 20
X1 or 1.6m7! L metal plate) at the same time, 9
After shaking and soaking at 0℃ for 24 hours, air dry at room temperature (20~2
5° C.) and a relative humidity of 93% for a predetermined number of days, the change in the metal piece is visually observed and evaluated.

The evaluation criteria are as follows.

Evaluation Surface condition 5 No change at all 4 Slight decrease in gloss, pitting formed in a very small part, slight contamination in the solution Change in 34 increased slightly 2 Significant change, rust occurring on about half of the surface 1 The sample aqueous solution changes significantly, the entire surface is covered with rust, the solution changes color significantly, and a precipitate forms.11) Put 7 g of the sample aqueous solution into the same test tube as in the case of l), and add 3 types of metal pieces (8 x 40 x il). , steel (B described later), copper, and aluminum) were immersed at 30±1°C.
The metal piece was left standing for 10 days, and then the metal piece was wiped lightly with gauze, washed with water and acetone, and dried. Changes in weight were measured and changes in appearance were visually observed and evaluated.

During the measurement, the lid was lightened to allow oxygen to flow, and evaporated water was replenished midway. Table 1 shows the types of metal test pieces used in these tests. Example 1 Using 0d4Na and 0d5Na- obtained in Reference Examples 1 to 5, aqueous solutions of predetermined concentrations were prepared, and the antirust ability was measured by measurement method 1). The results are shown in Table 2.

From the results in this table, it is extremely good for steel under any conditions, 0d5Na for copper, and 0d4 for aluminum.
It can be seen that Na exhibits excellent antirust effects. Example 2 Aqueous solutions of 0d4Na and 0d5Na with predetermined concentrations were prepared, and the rust preventive power was measured using measurement method 11). The results are shown in Table 3.

From the results in this table, it can be seen that good results were obtained in all cases except for a slight increase in aluminum at the high concentration of 0d4Na.

In the case of 0d5Na, the aluminum became slightly gray, but there was almost no change in weight. Therefore, the rust inhibitor of the present invention shows excellent effects on steel under all conditions, including 0d5Na aluminum and 0d4Na aluminum at high temperatures.
It was found that all cases exhibited excellent effects except for the case of copper.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (I) (In the formula, n and n' are numbers from 4 to 10, and X is a hydrogen atom or CO
OZ and Z represent a hydrogen atom, a lower alkyl group, or an alkali metal or ammonium ion, and at least three of Z are an alkali metal or ammonium ion. ) A rust preventive agent characterized by comprising a salt of a tetra or pentacarboxylic acid.