JPS5921951B2 - anticorrosion agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to an anticorrosive agent that is used by being added to various aqueous media.

(Prior art) Various anti-corrosion agents are added to water-based media that come into contact with iron, such as cooling system water, hydraulic water for tanks, full-fill storage water, and water-soluble abrasives, to prevent iron from corroding. .

As anticorrosive agents used for these purposes, inorganic compounds such as chromates, dichromates, nitrites, and phosphates, and organic compounds such as organic acid salts of amines are used. All of them have practical difficulties and have not yet been fully satisfactory. For example, chromate and dichromate are highly toxic and pose a danger when used.
The use of nitrites tends to be avoided because of the risk of forming nitrosamines, which are carcinogens, and wastewater containing these hydrochloric acids is classified as wastewater containing hazardous substances under the Water Pollution Control Act. Regulations require wastewater treatment equipment, which requires huge pollution control costs.

Furthermore, there is a tendency for wastewater containing phosphates to be regulated as a cause of eutrophication of rivers, lakes, oceans, etc.

Among amines, organic acid salts, and the like, known anticorrosive agents have drawbacks such as poor anticorrosive properties or easy foaming.

(Objective of the Invention) An object of the present invention is to provide an anticorrosive agent which has an excellent anticorrosive effect and does not have the drawbacks of conventional products as described above.

(Structure of the Invention) As a result of many years of research, the inventors learned that the object of this invention can be achieved by using an alkali metal salt or amine salt of cyclohexylpropionic acid, and completed this invention. .

That is, the present invention is an anticorrosive agent characterized by containing an alkali metal salt or amine salt of cyclohexylpropionic acid as an active ingredient. The configuration of this invention will be explained in more detail.

(Active ingredient) The compound referred to as cyclohexylpropionic acid in this invention has the following structural formula and is a known compound described in various documents related to organic chemistry.

) CH2-CH2-COOH To produce an alkali metal salt of cyclohexylpropionic acid, cyclohexylpropionic acid and an aqueous solution of an alkali metal hydroxide such as potassium hydroxide, sodium hydroxide, lithium hydroxide, etc. are mixed and reacted. to prepare a concentrated aqueous solution of the alkali metal salt of cyclohexylpropionic acid.

To produce the amine salt of cyclohexylpropionic acid, cyclohexylpropionic acid and an organic amine may be mixed, stirred, and reacted.

The alkaline substances or amines reacted with cyclohexylpropionic acid do not necessarily have to be in stoichiometric equivalents. In other words, it may be selected as appropriate to suit the pH required by the conditions of use as an anticorrosive agent. When using the alkali metal salt or amine salt of cyclohexylpropionic acid obtained in this manner as an anticorrosive aqueous medium, the above-mentioned concentrated aqueous solution may be diluted as appropriate.

The anticorrosive agent of this invention usually contains an active ingredient of about 0.05 to 2
．． It is used at a concentration of 0% by weight, preferably about 0.2-1.0% by weight.

If the concentration is less than about 0.05% by weight, the anticorrosion effect will be insufficient, and if the concentration exceeds about 2.0% by weight, the anticorrosion effect will not increase, which is uneconomical. (Effects of the Invention) The anticorrosive agent of the present invention can be used for cooling system water. When used in aqueous media that come into contact with ferrous metals, such as hydraulic water in tanks, full storage water, and water-soluble abrasives, it is as effective as or more effective than conventional anticorrosive agents, and does not cause foaming. .

Furthermore, there is no sanitary danger when using it, and there is no need to particularly consider water pollution due to wastewater, so no special wastewater treatment equipment is required. (Examples of the Invention) Examples will be shown to explain the present invention in more detail, but the present invention is not limited to the following examples in any way.

EXAMPLE Three types of anticorrosive agents of the present invention and three types of conventional anticorrosive agents were diluted with tap water to prepare test water and subjected to the following tests.

(1) Test method (a) Casting swarf immersion method Approximately 157 dry-cut casting swarfs (FC-25, 8-12 mesh) were collected in a Petri dish (inner diameter approximately 607 m), and approximately 25 me of test water was added to the After shaking and allowing to stand for about 10 minutes, the test water was removed by tilting or a method, and the state of rust observed from the bottom of the Petri dish was examined over time.

0)) Mild steel plate immersion method In a 100me wide-mouth bottle, add 100 m2 of test water and a clean mild steel plate (soft steel plate SS-4 which was sanded with #240 sandpaper and degreased and washed sequentially with naphtha, methanol, and water).
1.35 x 50 x 1.67 m), cover with a lid and
After standing at a constant temperature of ℃ for 72 hours, test. The specimen was taken out and its appearance was observed, and the change in weight before and after immersion was measured.

The corrosion protection rate was determined from the weight change using the following formula.

(c) Defoaming test 50 mt of test water was collected in a 100-me graduated cylinder,
The container was tightly capped and vigorously shaken 10 times in the vertical direction, and the state of foam was observed.

) Preparation of test anticorrosion agent and anticorrosion water (a) Test anticorrosion agent A cyclohexylpropionate potassium salt B cyclohexylpropionate diisopropanolamine salt C
Cyclohexylpropionate diethanolamine salt D Paratertiary butylbenzoic acid diethanolamine salt E Sodium hydrogen phosphate F Ammonium dichromate (b) Preparation of test anticorrosion water Dilute each anticorrosive agent with tap water to prepare test anticorrosion water. Prepared.

For test methods (a) and (c), the corrosion inhibitor concentration is
0.5q1) (weight), 0.2 for test method 0))
(Defined as F6 (weight). The following preparation method was used depending on the anticorrosive agent.

Anticorrosive agent A: A chemical equivalent of cyclohexylpropionic acid was gradually added to a 5% (weight) aqueous solution of potassium hydroxide while stirring to prepare an aqueous solution of a neutralized salt, which was further diluted to a predetermined concentration and tested.

Anticorrosive agent B: Chemical equivalents of cyclohexylpropionic acid and diisopropanolamine were mixed and thoroughly stirred to prepare a salt, which was diluted to a predetermined concentration and tested.

Anticorrosive agent C and anticorrosive agent D: Same as anticorrosive agent B.

Anticorrosive agent E and anticorrosive agent F: Commercially available reagents were diluted to predetermined concentrations and tested.

(3) Test results Table 1 shows the test results.

As shown by the above test results, the anticorrosive agent of the present invention has performance equivalent to or better than conventional anticorrosive agents in terms of anticorrosion and antifoaming properties, and has anticorrosive properties such as dichromate and other toxic substances. It is an industrially excellent anticorrosive agent that causes no problems and does not require special wastewater treatment equipment to deal with environmental pollution.

Claims (1)

[Claims] 1. An anticorrosive agent characterized by containing an alkali metal salt or amine salt of cyclohexylpropionic acid as an active ingredient.