WO1999005089A1 - Novel n-alkyl-hydroxybenzylamines, preparation method, uses and compositions containing them - Google Patents

Abstract

The invention concerns novel N-alkyl-hydroxybenzylamines of formula (I) in which: R1 and R2, which are identical or different, represent a hydrogen atom or a monohydroxylated or polyhydroxylated C1-C8 alkyl radical, provided that R1 and R2 do not simultaneously represent each a hydrogen atom; Q represent a -OH or -NH2 radical; Z represents a hydrogen atom or the group (a) in which R1 and R2 have the same definitions as above and Y1 and Y2 represent a hydrogen atom or the radical -OH, provided that Y1 and Y2 do not simultaneously represent each a hydrogen atom. The invention is useful for treating metal surfaces both against corrosion and for improving subsequent paint adherence.

Description

 NEWS N-ALKYL-HYDROXYBENZYLAMINES,

THEIR PREPARATION PROCESS, THEIR APPLICATIONS

AND COMPOSITIONS CONTAINING THEM

The subject of the invention is new N-alkyl-hydroxybenzylamines.

It also relates to a process for the preparation of these N-alkyl-hydroxybenzylamines as well as their applications in the treatment of metallic surfaces both against corrosion and in favor of a subsequent improvement in adhesion of paints, and the compositions which contain them to active substance title.

It has already been proposed to use in the fight against corrosion of metallic surfaces - polymers of polyvinylphenol structure

(document EP-0-091 166), condensation copolymers of the preceding polyvinylphenols with formalin-phenol resins, tannins and lignins (document EP-0 319 017 B1), - substituted polyvinylphenols (document US-A-

4,978,399),

- substituted poly-ortho-methylene-phenols (document WO 95/28449),

- substituted poly-ortho-methylene-bisphenols (documents WO 95/28509, WO 97/04144 and WO 97/04145 and

- Monomer molecules comprising a substituted mono- and bis-amino phenolic nucleus (respectively described in documents EP-0 276 072 B1 and EP-0 517 356 B1). The known structures, both polymeric and monomeric, are not entirely satisfactory, in particular from the point of view of obtaining, after treatment, surfaces which simultaneously offer excellent properties in terms of resistance against corrosion as from the point of view of adhesion of the paints applied to it. The object of the invention is therefore, above all, to remedy the shortcomings of the prior art and to provide N-alkyl-hydroxybenzylamines more effective than the already known polymer and monomer products. And the Applicant Company has had the merit of developing new N-alkyl-hydroxybenzylamines which make it possible to achieve this goal.

The new N-alkyl-hydroxybenzylamines in accordance with the invention are characterized in that they have the general formula

in which

- R _] _ and R ₂ , which are identical or different from each other, represent a hydrogen atom or a C ₁ to C ₈ alkyl radical mono- or polyhydroxyl, R ₁ and R ₂ cannot represent simultaneously each a hydrogen atom,

- Q represents a radical -OH or -NH ₂ , - Z represents a hydrogen atom or the group

-CH- -N;

^{^} R-

in which R _j _ and R ₂ have the meanings indicated above and

- Y ₁ and Y ₂ represent a hydrogen atom or the radical -OH, Yι_ and Y cannot each simultaneously represent a hydrogen atom. The molecules of formula (I) have a very strong affinity for metallic surfaces; this affinity is due to their chelating power; these molecules form a covering network on the metal surfaces, promoting both the adhesion of a coating and that of a protective paint; moreover and this is their main function, they avoid any corrosion by oxidation of the support.

In other words, the invention therefore also relates to the use of N-alkyl-hydroxybenzylamines of formula (I) in the treatment of metallic surfaces both against corrosion and in favor of a subsequent improvement in adhesion of paints .

By their internal structure of orthophenolic form, these molecules are both reducing and chelating iron; they therefore limit the metal oxidation of the support and more particularly the oxidation of Fe (0) to Fe (II) and Fe (III). They therefore advantageously replace the known polymer structures which still have the drawback of being poorly defined. In addition, these molecules do not degrade the metal support by chemical attack; they therefore preserve the integrity of the part comprising the treated surface.

Last but not least, they replace the chromium phosphating treatments currently used.

The process according to the invention for the preparation of the compounds of formula (I) is characterized in that one uses a Mannich condensation in the presence of formalin from an amine of formula:

H — N — R,

(II)

in which R ^ _ and R ₂ have the meanings indicated above, on a reducing phenol of formula:

in which Q, Yl and Y2 have the meanings indicated above, the reaction scheme being

⁽ II ⁾ (III) (I) in which m is equal to 1 or 2 and represents the stoichiometry of formaldehyde either for a monosubstitution, Z then representing H, or for a disubstitution, Z then representing the group

NOT-

The starting materials of formulas (II) and (III) are commercially available or are easily accessible by synthesis by techniques well known to those skilled in the art.

The above-mentioned condensation reaction can be carried out in the presence of an inert organic solvent. The inert organic solvent can be advantageously chosen from aliphatic essences from the group comprising hexane, heptane, octane, nonane and dodecane, from the chlorinated derivatives of the group comprising dichloromethane, 1, 2-dichloroethane, chloroform, trichlorethylene and tetrachlorethylene, among the dialkyl ethers of the group comprising diethyl- and dipropyl ethers as well as dibutyl ethers, among polyalkoxy-alkanes, polyalkoxy -alcohols and alcohols, the preferred solvents being benzene, toluene and xylene.

The amount of solvent used in the reaction is not critical. Preferably, the reaction is carried out in the presence of a solvent forming a hetero-azeotrope with water at reflux of this azeotrope; thus, the water formed by the reaction is subtracted from the reaction medium as it is formed. This technique provides increased productivity and conversion.

The reaction is carried out at temperatures from 50 to 200 ° C, preferably from 50 to 150 ° C and even more preferably from 50 to 100 ° C.

It can be implemented under atmospheric pressure as under autogenous formaldehyde pressure _; however, preferably, it is carried out at atmospheric pressure under reflux of formaldehyde.

The molar quantities of formaldehyde used relative to the amine of formula (II) can vary in the ratios from 0.1 to 5; is preferably used an amount of formaldehyde between 0.5 and 2.5 mol / mol of amino _of formula (II) and, more preferably, 1 to 2 mol / mol.

The molar amounts of phenol of formula (III) used relative to the amine of formula (II) can vary in the ratios from 0.1 to 2; preferably a quantity of phenol of 0.4 to 1.5 mol / mol of amine is used and, more preferably still, of 0.5 to 1 mol / mol.

The reaction can be carried out in the absence of catalyst or in the presence of catalysts; preferably, the operation is carried out in the presence of a basic catalyst which can be chosen from aliphatic tertiary amines such as trimethylamine, methyldiethylamine or triethylamine, tertiary anilines such as dimethylaniline, diethylaniline or cyclic amines such as pyridine or imidazoles; it is also possible to use alkaline bases such as soda, potash or lime. The amount of catalyst used relative to the amine of formula (II) is from 0.1% to 5% -mol of catalyst per mol of amine.

The reaction conditions are maintained for a time necessary and sufficient to reach a conversion rate of the amine greater than 95%.

Thanks to their particularly advantageous properties, the N-alkyl-hydroxybenzylamines in accordance with the invention can be used in the form of corrosion protection compositions in processes which do not require chromic treatment.

It follows that the corrosion inhibiting composition according to the invention is characterized in that it comprises an effective amount of at least one N-alkyl-hydroxybenzylamine of formula (I) in solution or in the form of a dispersion in water or in a solvent optionally in the presence of surfactants, wetting agents and dispersants necessary for the formulation of the active material.

The term “effective quantity” denotes the quantity of active material necessary and sufficient to give the treated part protection against corrosion, respecting a resistance to the salt spray test as defined in standard ISO 9227 of at least 100 hours.

In practice, the composition according to the invention contains from 0.01 to 400 g, preferably from 0.2 at 100 g per liter of active ingredient.

The composition in accordance with the invention can be sold in the form of a concentrate.

The active ingredient content of the concentrate is at most that of its limit solubility in the solvent used.

When the solvent is water, the content in question can reach 50% by weight, that is to say 500 g / 1 of solvent or water. At the time of use, the concentrate is diluted with the necessary amount of solvent or water.

Water is preferred as solvent for the composition in accordance with the invention, but it is also possible to use aliphatic essences, aromatic solvents such as benzene, toluene, xylene and alkylnaphthalene, halogenated solvents, alcohols, ethers, polyethers, ketones and mixtures of these solvents. As indicated above, exclusively aqueous formulations are preferred. The pH of the composition according to the invention is from 1 to 12, preferably from 4 to 9, and even more preferably from 5 to 8.

To adjust this pH, an organic or mineral acid is used and, preferably, a couple of acids, one of which is organic and the other mineral; the precise adjustment of the pH of the composition is carried out by the addition of small amounts of mineral or organic bases.

Among the organic acids which can be used, mention may be made of acetic acid, tartaric acid, oxalic acid, citric acid, adipic acid, acrylic and methacrylic acids, succinic acid and also the polycarboxylic acids of group comprising maleic, malonic, glutamic, aspartic, gluconic, lactic, gallic, iminodiacetic, salicylic, sulfosalicylic, glycollic acids. Among the mineral acids, mention may be made of hydrochloric acid, sulfuric acid, phosphorous acid, nitric acid, sulfamic acid and phosphoric acid.

The components of the "organic acid - mineral acid" couple as well as the pH are chosen so as to obtain the optimum corrosion protection performance.

The base used to adjust the pH with precision is preferably chosen from alkylamines from the group comprising diethylamine, isopropylamine, ethylene diamine, diethylenetriamine, triethylene tetramine, hexamethylene tetramine, amines with OH function of the group comprising hydroxylamine, mono- and poly-ethanolamines, isopropanolamines, morpholine, ammonium carbonate, ammonia, soda and potash.

It is possible to adjust the pH using one or more of these compounds used at a rate of 0.1 to 100 g / l, preferably 0.5 to 30 g / l in total. The composition in accordance with the invention may contain any other compound known to a person skilled in the art from the group comprising other corrosion inhibitors, adhesion promoters, dispersants, wetting agents, emulsifiers, thickeners, anti products - foam, plasticizers, anti-freeze products, fungicidal products, bactericidal products, soluble or insoluble resins, organic polymers, pigments, dyes and mineral fillers.

Among the other corrosion inhibitors which can be used, mention may be made of zinc phosphates and alkaline earth sulfonates used at concentrations of 0.05 to 2%.

Among the adhesion promoters which can be used, mention may be made of silanes, organo-titanates, zircoaluminate complexes of the type sold under the brand MANCHEM®.

Among the resins which can be used, there may be mentioned acrylic resins, chlorinated vinyl-acrylic copolymers and phenolic resins modified by Mannich reaction.

Among the fillers and pigments which can be used, mention may be made of silicas, silicates and silicoaluminates.

The composition in accordance with the invention can be used in the context of a process successively comprising:

a step of degreasing the surface of the part to be treated using any composition or technique known to those skilled in the art,

a step of rinsing the part to be treated, a step of treatment using the composition according to the invention by immersing the part in the composition, by spraying the composition on the surface of the part to be treated , or by application with a brush or an ink roller, at a temperature of 15 to 60 ° C, preferably from 15 to 40 ° C, optionally a step of rinsing with possibly hot water, a step of drying at a temperature of 40 to 160 ° C. A liquid or powder paint can then be applied by any paint application technique known to those skilled in the art.

When the composition is applied by immersion, the duration of immersion must be sufficient to lead to a uniform deposition of active material, it is generally less than 15 minutes and often between 30 and 180 seconds; the deposit thus obtained corresponds to a layer weight of the order of 0.5 to 15 g / m ² , or in active material from 0.1 to 15 gm ² of treated surface. EXAMPLE 1

Preparation of the isomers N-met yl-N- (1-deoxy-glucitol) 3,4-dihydroxyphenylmethylamine and N-methyl-N- (1-deoxy-glucitol) 2, 3-dihydroxyphenylmethylamine corresponding to the formulas:

HO OH

HO.

HO OH

^{^} OH

In a 500 ml reactor, equipped with an agitator, a thermometer, a reflux condenser, a "deanstark" (trade term to designate a distillation guard for withdrawing water from reaction) and from a dropping funnel, 70 g of toluene, 60 g of n-butanol, 11 g (100 mmol) of pyrocatechol, 23.4 g of N-methyl-glucamine (120 mmol) and 0 are charged. 8 g (10 mmol) 50% sodium hydroxide.

The temperature of the mixture is brought to 70 ° C., then 12.5 g (150 mmol) of 36% formaldehyde are introduced over 15 minutes.

It is heated to total reflux for 1 hour, then azeotropically distilled, over 2 hours, an amount of 9.5 g of water (ie 90% of the theoretical amount).

Then introduced by the dropping funnel 100 g of distilled water, then allowed to settle for 15 minutes at 80 ° C.

The aqueous phase which is stripped is collected (trade term for designating the entrainment of traces of solvent by distillation) in order to remove the residual traces of solvent.

116 g of a 29% solution are thus obtained. dry extract of the desired product consisting of two monosubstituted isomers:

N-methyl-N- (1-deoxy-glucitol) 3, 4-dihydroxyphenylmethylamine, N-methyl-N- (1-deoxy-glucitol) 2, 3-dihydroxyphenylmethylamine, which corresponds to a yield of 94%.

The two molecules being effective, we do not try to separate them.

This active material solution is directly usable for the formulation of a corrosion inhibiting composition.

EXAMPLE 2

Preparation of 2, 4bis (N-methyl-N- (1-deoxy-glucitol) a inomethyl) -6-hydroxyphenol and corresponding to the formula:

50 g of toluene, 50 g are charged into a 500 ml reactor equipped with an agitator, a thermometer, a reflux condenser, a "deanstark" and a dropping funnel. of n-butanol, 5.5 g (50 mmol) of pyrocatechol, 21.5 g of N-methyl-glucamine (110 mmol) and

0.4 g (5 mmol) 50% sodium hydroxide. The temperature of the mixture is brought to 70 ° C., then 11.7 g (140 mmol) of formaldehyde are introduced over 15 minutes to

36%.

The mixture is heated to total reflux for 1 hour, then azeotropically distilled, in 2 hours, an amount of 10.2 g of water (ie 100% of the theoretical amount). Then introduced by the dropping funnel 100 g of distilled water, then allowed to settle for 15 minutes at 70 ° C.

The aqueous phase which is stripped is collected in order to eliminate the residual traces of solvent.

96 g of a 28% solution of dry extract of the desired product are thus obtained, which corresponds to a yield of 95%.

This active material solution is directly usable for the formulation of a corrosion inhibiting composition.

EXAMPLE 3

Preparation of isomers 2, 4bis (N-methyl-N- (1-deoxy-glucitol) amino-methyl) -6-amino-phenol and 3, 5bis (N-methyl-N- (1-deoxy-glucitol) amino- methyl) -2-amino-phenol corresponding to the formulas:

50 g of toluene, 70 g are charged into a 500 ml reactor equipped with an agitator, a thermometer, a reflux condenser, a "dean-stark" and a dropping funnel of n-butanol, 5.5 g (50 mmol) of 2-amino-phenol, 21.5 g of N-methyl-glucamine (110 mmol) and 0.4 g (5 mmol) of 50% sodium hydroxide.

The temperature of the mixture is brought to 70 ° C., then 11.7 g (140 mmol) of 36% formaldehyde are introduced over 15 minutes.

The mixture is heated to total reflux for 1 hour, then azeotropically distilled, over 2 hours, an amount of 9.4 g of water (ie 98% of the theoretical amount).

Then introduced by the dropping funnel 100 g of distilled water, then allowed to settle for 15 minutes at 80 ° C.

The aqueous phase which is stripped is collected in order to eliminate the residual traces of solvent.

101 g of a 27% solution of dry extract of the desired product are thus obtained, which corresponds to a yield of 100%.

This active material solution is directly usable for the formulation of a corrosion inhibiting composition.

EXAMPLE 4

Preparation of N-methyl-N- (1-deoxy-glucitol) 2, 3, 4-tri-hydroxy phenylmethylamine corresponding to the formula:

HO OH CH,

^{^} OH

100 g of toluene, 200 g are charged into a 1 l reactor, equipped with an agitator, a thermometer, a reflux condenser, a "dean-stark" and a dropping funnel. of n-butanol, 25.2 g (200 mmol) of pyrogallol, 46.8 g of N-methyl-glucamine (240 mmol) and 1.6 g (20 mmol) of 50% sodium hydroxide. The temperature of the mixture is brought to 70 ° C., then 25.0 g (300 mmol) of 36% formaldehyde are introduced over 15 minutes.

It is heated to total reflux for 1 hour, then azeotropically distilled, in 2 hours, an amount of 21 g of water.

250 g of distilled water are then introduced through the dropping funnel, then allowed to settle for 30 minutes at 90 ° C. The aqueous phase which is stripped is collected in order to eliminate the residual traces of solvent.

242 g of a 31% solution of dry extract of the desired product are thus obtained, which corresponds to a yield of 99%. This active material solution is directly usable for the formulation of a corrosion inhibiting composition.

EXAMPLE 5 Preparation of the N-methyl-N- (2-hydroxyethyl) 3,4-dihydroxyphenylmethylamine and N-methyl-N- (2-hydroxyethyl) 2,3-dihydroxyphenylmethylamine isomers corresponding to the formulas:

100 g of toluene, 100 g are charged into a 500 ml reactor equipped with an agitator, a thermometer, a reflux condenser, a "deanstark" and a dropping funnel. of n-butanol, 22 g (200 mmol) of pyrocatechol, 18 g of 2- (methylamino) -ethanol (240 mmol) and 1.6 g (20 mmol) of 50% sodium hydroxide.

The temperature of the mixture is brought to 70 ° C., then 25 g (300 mmol) of 36% formaldehyde are introduced over 15 minutes.

The mixture is heated to total reflux for 1 hour, then a quantity of 21.6 g of water is distilled azeotropically over 2 hours.

200 g of distilled water are then introduced through the dropping funnel, then the mixture is left to settle for 30 minutes at 80 ° C.

The aqueous phase which is stripped is collected in order to eliminate the residual traces of solvent.

146 g of a 18.5% solution of dry extract of the desired product are thus obtained.

This active material solution is directly usable for the formulation of a corrosion inhibiting composition.

* * *

In the examples which follow, the effectiveness of the N-alkyl-hydroxybenzylamines in accordance with the invention is illustrated for the inhibition of corrosion of metal surfaces. In this regard, the N-alkyl-hydroxybenzylamines in accordance with the invention according to examples 1 to 3 and a molecule of the prior art are used in a process the steps of which are identified in Table I by indication of the products used implementation, duration, temperature and embodiment.

The compositions used are as indicated below: Composition A1 according to the invention: adipic acid 0.5 g / 1 phosphoric acid 0.4 g / 1 molecule of example 1 1 g / 1 sodium hydroxide 0.15 g / 1 triethylene tetramine qs pH 6, 0

Composition A2 according to the invention:

Identical to the composition Al, but the molecule tested is that of Example 2.

Composition A3 according to the invention:

Identical to the composition Al, but the molecule tested is that of Example 3.

Composition Cl according to the invention:

Identical to the composition Al, but the molecule tested is that described in patent EP No. 0 319 017-A2 (which claims priority from the application US SN 128 673) and having the formula

TABLEAU I

TABLE I

The RIDOLINE 417 CF and RIDOSOL 161 CF products are degreasing compositions based on alkaline derivatives and surfactants sold by the Applicant Company.

The method is applied to two types of test pieces, one made of cold-rolled mild steel 0.7 mm thick and of ZES quality NFA 36.401 and the other made of zinc-coated mild steel of equal thickness. at 0.7 mm and of NFA 36.260 quality marked EZ.

These test pieces are in the form of panels, the width and length of which are 10 and 20 cm respectively.

Also for comparison, the same test pieces were subjected to a conventional phosphating treatment with chromic post-rinsing, the test pieces being treated according to a standard range of amorphous phosphating, the steps being: - degreasing using DURIDINE F 775 CF 1% v / v +

RIDOSOL 162 CF 0.1% v / v at a temperature of 50 ° C for

150 seconds, rinse at room temperature for 60 seconds, chromic rinse using DEOXYLYTE 41 0.1% v / v at room temperature for 40 seconds, rinse with deionized water at room temperature for 60 seconds, drying at 80 ° C for 300 seconds. The DURIDINE F 775 CF and RIDOSOL 162 CF products, which are respectively aqueous solutions based on phosphoric acid and surfactants, are marketed by the Applicant Company.

After the treatment according to Table I and after the given phosphating treatment, the corrosion resistance and the adhesion of an applied paint are determined for the treated surfaces.

The corrosion resistance is determined by the salt spray test according to ISO Standard 9227. In the context of this test, the specimens are made to have an inverted V-shaped wound.

After 100 hours of exposure to salt spray, the total thickness of the corrosion on both sides of the wound is measured. The result is considered

- excellent and rated "++" for corrosion of 0 to 4 mm,

- medium and rated "+" for corrosion greater than 4 mm and up to 7 mm,

- bad and marked "-" for corrosion greater than 7 mm.

The adhesion of a paint is determined by the evaluation of the resistance to the grid according to Standard NFT 30.038.

The results are noted from 0 to 5. The 0 rating corresponds to excellent adhesion without any peeling and the 5 rating to a complete peeling of the paint.

The results recorded are collated in Table II. TABLE II

It is clear from examining this table that the compositions based on the molecules in accordance with the invention give, on the one hand, better results than the molecules of the prior art comprising a phenol molecule in their structure and, on the other hand, results in all respects comparable to conventional phosphating techniques without having the drawback of requiring chromic post-rinsing.

Compared to these latter techniques, they also provide an answer to energy saving requests because they apply at room temperature, are simple to implement and do not require rinsing after treatment.

Claims

1. New N-alkyl-hydroxybenzylamines characterized by the fact that they have the general formula

in which RL and R ₂ , which are identical or different from each other, represent a hydrogen atom or an alkyl radical C-ι_ to C ₈ mono- or polyhydroxyl, R and R ₂ can not simultaneously represent each a hydrogen atom, Q represents a radical -OH or -NH ₂ , Z represents a hydrogen atom or the group

in which R ^ _ and R ₂ have the meanings indicated above and - YL and Y represent a hydrogen atom or the radical -OH, Y ₁ and Y ₂ cannot each simultaneously represent a hydrogen atom. 2. Process for the preparation of N-alkyl-hydroxybenzylamines according to claim 1, characterized in that a Mannich condensation is used in the presence of formalin from an amine of formula: H — N — R _n (II) in which R; L and R have the meanings indicated above, on a reducing phenol of formula:

in which Q, Yl and Y2 have the meanings indicated above, the reaction scheme being

⁽ II) (III) (I) in which m is equal to 1 or 2 and represents the stoichiometry of formaldehyde either for a monosubstitution, Z then representing H, or for a disubstitution, Z then representing the group ^' N- 3. A corrosion inhibiting composition characterized in that it comprises an effective amount of at least one N-alkyl-hydroxybenzylamine of formula (I) in solution or in the form of a dispersion in water or in a solvent optionally in the presence surfactants, wetting agents and dispersants necessary for the formulation of the active material. 4. Composition according to claim 3, characterized in that it comprises from 0.01 to 400 g, of preferably 0.2 to 100 g per liter of at least one N-alkyl-hydroxybenzylamine. 5. Concentrate comprising up to 500 g per liter of solvent or water of at least one N-alkyl-hydroxybenzylamine according to claim 1 and capable of providing the comosition according to claim 3 by dilution with a necessary quantity of solvent or of water. 6. Method for implementing a composition according to one of claims 3 and 4, characterized in that it successively comprises: a step of degreasing the surface of the part to be treated using any composition or technique known to those skilled in the art, a step of rinsing the part to be treated, - a treatment step using the composition according to the invention by immersing the part in the composition, by spraying the composition on the surface of the part to be treated, or by application with a brush or an inking roller, at a temperature of 15 to 60 ° C, preferably from 15 to 40 ° C, optionally a step of rinsing with water if necessary hot, a drying step at a temperature of 40 to 160 ° C. 7. Use of N-alkyl-hydroxybenzylamines of formula (I) in the treatment of metallic surfaces both against corrosion and in favor of a subsequent improvement in adhesion of paints.