FI72536C - FOERFARANDE FOER FRAMSTAELLNING AV KORROSIONSINHIBITOR. - Google Patents

Description

72536

METHOD OF MANUFACTURING AN ANTI-CORROSION AGENT - FÖRFARANDE FÖR FRAMSTÄLLNING AV KOBBOSIONSINHIBITOR

The present invention relates to a process for the preparation of a corrosion inhibitor, in which process the crude soap obtained from the pulp cooking or the product of its purification and / or fractionation is converted into a neutralized product which prevents corrosion.

Corrosion inhibitors based on pine residues obtained as a distillation residue from crude tall oil are already known. For example, FI patent publication 53 9 33 discloses an anti-corrosion agent in which the binder is calcium oxide neutralized tall oil pitch. The neutralization of tall oil pellets takes place in a solvent, such as a mixture of white spirit and ethanol, optionally with the aid of a catalyst, at a temperature of up to 250 ° C, according to the examples of the publication, at about 170-200 ° C. FI patent application 832428 further discloses a corrosion inhibitor based on alcohol-esterified tall oil pitch. Such pitch can be used as such as a corrosion inhibitor or other corrosion agent; as a binder for a rose inhibitor. The small esterification is carried out using plasticizer and possibly a catalyst at a temperature which, according to the examples given, is about 220-250 ° C.

The effectiveness and usability of said corrosion inhibitors made of earthen silicon are essentially based on their good adhesion to the metal surface to be protected against corrosion. However, both the neutralization of tall oils according to FI patent 58933 and the esterification of tall oils according to FI patent application 832428 have the disadvantage of the high temperature required, which makes the corrosion inhibitor manufacturing process cumbersome and expensive.

It is an object of the present invention to obviate said drawback of the known methods by providing a process for the preparation of a corrosion inhibitor which can use substantially lower temperatures and which is also less critical for the starting material used; Namely, other 2 72536 purification or fractionation products obtained from crude sucrose or even crude soap as such can be used as starting material in the process. The process according to the invention is characterized in that the crude soap or its purification and / or fractionation product, which has first been neutralized with alkali, is treated at a temperature of 50-90 ° C with a cation-exchange metal compound so that the alkali metal cations are replaced by cations of said metal.

In addition to the low reaction temperature, the process according to the invention has the advantage that the crude soap or the product obtained therefrom, which has been neutralized with alkali, reacts directly with the metal compound in aqueous solution, so that no organic plasticizer or solvent or catalyst is required. This also applies to said alkali neutralization, which is the first step in the manufacturing process when the starting material is other than crude soap. The organic solvent is only needed when the product obtained by the reaction is applied to the surface to be protected against corrosion.

The simplest and most preferred embodiment of the invention is that the starting material used in the pulp cooking is a crude soap formed from sodium salts, which is converted into a cation exchange corrosion inhibitor. This avoids purification and fractionation of the crude bed. The impurities in the crude cant do not interfere in any way with the cation exchange reaction and do not affect the properties of the product to be obtained.

Another useful starting material is tall oil pitch from the distillation of refined tall oil, which is first neutralized with sodium or potassium hydroxide and then converted to an anti-corrosion product by cation exchange. It is further possible to use as starting material some other fraction obtained by fractional distillation of tall oil, such as distilled tall oil from fatty acids or fraction from rosin acids, or even crude distilled tall oil as such. All of these alternatives require neutralization with alkali prior to the cation exchange reaction.

Il 3 72536

Suitable metal compounds for use in the process of the invention include zinc and lead compounds such as zinc chloride and lead nitrate, which are present in the working examples below. However, compounds of a number of other metals such as calcium, cobalt, chromium, copper, magnesium, manganese, molybdenum, nickel, iron and tin, mainly various salts, oxides and hydroxides, may also be considered.

As such, the product according to the invention prevents corrosion mainly on the basis of its mechanical protective effect. Namely, the product is easy to apply, the protection cc open to the surface in a tough, tight and impermeable layer. However, it is also possible that the product is mixed with another known, commercially available corrosion inhibitor, such as, for example, kaums sulfonate, whereby the product acts as a binder for this.

The product prepared according to the invention is preferably applied to a surface to be protected against corrosion in a uniform layer using a suitable organic solvent, such as solvent naphtha.

The invention is further illustrated by the following examples. The amounts of the substances mentioned in the examples are by volume to 100 parts of a fatty acid fraction obtained by distilling crude tall oil with a rosin acid content of less than 5%, to a portion of 50% sodium hydroxide solution and 350 parts of water. The solution is heated at 100 ° C for 2 hours.

To 100 parts of the neutralized solution obtained are mixed with 60 parts of 20% 1N lead nitrate and the mixture is heated to 65 ° C. The result is a pasty product from which the aqueous phase is decanted apart. To apply the product to the surface to be protected from corrosion, it is dissolved in 1 solvent gasoline. The solution spreads well and forms a dense film which adheres firmly to the surface as the solvent evaporates. 50% of the tall oil pitch obtained as a distillation residue from crude pine oil, 50 parts of a distilled oil fraction with about 50% resin acid and a; 10 parts of 50% sodium hydroxide solution and 50 parts of water are mixed together. The resulting mixture is heated at 90 ° C for 2 hours.

To 100 parts of the neutralized mixture obtained are added 160 parts of a 20% solution of lithium nitrate and the mixture is heated to 600 DEG C. The aqueous phase is separated from the paste-like product obtained by decantation. To apply the product to the surface to be protected from corrosion, it is dissolved in solvent gasoline. The solution spreads well and forms a dense film which adheres firmly to the surface as the solvent evaporates.

Example 3 100 parts of tall oil pitch (acid number 31) obtained as a distillation residue from crude tall oil, 4 parts of 50% sodium hydroxide and 100 parts of water are mixed together. The resulting mixture is heated at 90 ° C for 2 hours.

To 100 parts of the resulting neutralized mixture is added 50 parts of a 20% zinc chloride solution and the mixture is heated to 75 ° C. The aqueous phase is decanted separately from the porridge-like product obtained. To apply the product to the surface to be protected from corrosion, it is dissolved in solvent gasoline. The solution spreads well and forms a dense film which adheres firmly to the surface as the solvent evaporates.

Example 4 To 100 parts of crude filtrate from a sulphate cellulose cooking process with a dry matter content of 64%, 80 parts of a 20% zinc chloride solution are added and the mixture is heated to 65 ° C. The aqueous phase is separated from the resulting rigid product by decantation. To apply the product to the surface to be protected from corrosion, it is dissolved in solvent gasoline. The solution spreads well and forms

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5 72536 as the solvent evaporated, a dense film adhering firmly to the surface.

It will be clear to a person skilled in the art that the various embodiments of the invention are not limited to the examples given above but may vary within the scope of the appended claims.

Claims (6)

725 36 A process for the preparation of a corrosion agent, in which the raw soap obtained from pulp cooking or its cleaning and / or fractionation product is converted into a neutralized anti-corrosion product, characterized in that the raw soap or its cleaning and / or fractionation product first neutralized with alkali is treated at 50-90 ° C with a cation exchange metal compound such that alkali metal cations are replaced by cations of said metal. Process according to Claim 1, characterized in that the starting material is a crude sodium salt formed in the pulp cooking, which is converted into an anti-corrosion product by cation exchange. Process according to Claim 1, characterized in that the starting material is pine pitch obtained from the distillation of refined tall oil, which is first neutralized with sodium or potassium hydroxide and then converted into a corrosion inhibitor by cation exchange. Process according to one of Claims 1 to 3, characterized in that the cation exchange is carried out using zinc! lead compound. Process according to one of Claims 1 to 4, characterized in that the cation exchange is carried out at a temperature in the range from about 60 ° C to 7 ° C. Process according to one of Claims 1 to 5, characterized in that another known corrosion inhibitor is mixed into the product obtained by cation exchange. Il