US2160406A - Product for inhibiting the attack on metals by acids or salts and its applications - Google Patents

Description

Q Patented May 30, i939 ICE PRODUCT FOR INHIBITING THE ATTACK N METALS BY ACIDS OB SALTS AND ITS APPLICATIONS Jacques Edouard Julien Georges Mascr,

Premery, France, assignor to Etabllssements Lambiotte Freres Premery (Nievre), France, a

corporation of ljrance ,No Application November 17, 1936,

Serial No. 111,336. 1935 6 Claims.

It is known that metals are attacked by acids in the absence of oxygen under conditions which depend both upon the nature of the metal and upon that or the acid.

In principle for a given acid the attack is more rapid, that is to say the dissolution is more rapid,

'if the inetal is situated lower in the scale of so- .Now according to the present invention it has been observed the oils obtained in the carbonization of wood have a very much greater inhibiting power for equal weight of the product employed, than that of all known compositions and an efiicaciousness which is quite general in all cases.

It is known that in the carbonization of wood a pyroligneous liquid is obtained which by distillation gives crude wood spirit which contains besides methanol, methyl acetate, acetone and allyl alcohol, a fraction of oils which will be referred to as crude wood spirit oils, which may be separated either by rectification or by dilution of the crude wood spirit with water.

These oils have a density between 0.890 and 0.935, most generally 0.910 to 0.925. They distil from 50-220" C. 80-90% passingon the average from l-130 C. to 205-210 C. They are rich in ketonic products (30-45% calculated as acetone) and allyl compounds (IO-30% calculated as allylalcohol) hydes, diketones, alcohols, hydrocarbons, furane and cyclopentane derivatives, amines, and other products which are unknown or not identified at present but which contribute for their part to tliil: special and characteristic properties of these 0 According to the present invention the unexpected'discovery has been made that these oils and all the fractions which are still very complex and which can be separated therefrom in one way or another exhibit inhibitory properties towards the attack on metals by acids or strongly dissociatedsadts.

' They may thus be very usefully employed for To sum up, these oils contain ketones, aide- In France December 17,.

preventing if not. entirely at least almost entirely attack on a metal whenever the latter is put into contact with an acid or a salt which attacks it. This is particularly the 'case with cleaning, pickling, or treatment of metals by acids, and in the case of scaling metallic surfaces by acids. It is sufiicient to mix the oils with the pickling or scaling baths used, and their presence in these baths does not at all alter the solubility in the acid of the oxide or scale. It should likewise vbe added that their wetting power facilitates their action and renders it regular.

But though these crude wood oils may be used for this purpose they have the disadvantage of not being entirely soluble in aqueous solutions of acids and of consequently giving rise to a greater or less degree to blackish tars which are deposited upon the walls of the receptacles. 1

To remedy this disadvantage it has been observed that' it is sufiicient to destroy by resinifyingthe unstable components of the oils, for example by bringing them to boiling in an acid medium, then in extractingfrom the oils thus treated the active, soluble and stable products' is added 1 part by volume of 7% hydrochloric.

acid or 10% sulphuric acid. The mixture is brought to boiling under a reflux for 10 hours.

After cooling the lower aqueous layer representing1.05 to 1.10 parts by volume is decanted,

clarified, and constitutes a stable extract containing 7-10% of dissolved active crude wood spirit oils.

The residual oil about 0.9 part by volume may be extracted again by agitation in the cold with an equal volume of acid as described above and give a new quantity of extract only half as rich as the above extract.

Thus systematic extractions may be combined on this principle. 1.

A practically deodorized extract may be ob tained by eliminating from the above extracts by distillation with a column, a first fraction of 10 which entrains the most volatile and strongly odoriferous constituents. e

' This distilled fracthn constitutes moreover a I stable and soluble very strongly active extract.

In. the following there are given a certain number of results of experiments with extracts of wood oils mixed with baths for pickling or scaling.

1. Pickling baths.

The tests were eflected upon portions of drawn iron tube and pickled and cleaned.

"The weight losses per square meter per hour were for an average duration oi- 60 hours 250 hours I (a) Treatment in the'cold (W C.) with a solution a pure hydrochloric acid with 23' aroma of Cl per 100 cco.

Pure hydrochloric acid alone 389 Pure hydrochloric acid+1% ersenious anhydride 332 Pure hydrochloric acid+l% oi aniline.--" 179 Pure hydrochloric acid+5% oi iormol 6. 17 8. 02 Pure hydroc on +l% of crude wood s 2.09 8.62 Pure hydrochloric acid+107 of a 69% sulphuric acid extract of dissolved wood oils 2.80 4.13 Pure hydrochloric acid+l0% of a 710% hydrochloric acid extract oi dissolved wood oils 2. 25 3. 43

(0) Treatment in the cold (20 C.) with a solution of pure sulphuric acid with 30.6 grams per 100 coo.

Pure sulphuric acid alone; 262 Pure sulphuric acid+l% oi anilin 155 Pure sulphuric acid+l% oi iormol (30%)-.. 5. 37 Pure sulphuric acid saturated with arsenious anhydride 0. 792 1. 31 Pure sulphuric acid+10% of a 6-8% sulphuric acid extract of dissolved wood oils. 0. 540 0. 615 Pure sulphuric aci d+10% of a 3-6% deodorised sulphuric acid extract of dissolved wood oils 0.885 1. 87

(4:) Hot treatment (6' 0 C.) with (isolation of pure sulphuric acid with 21.91 gram per 100 cce.

Pure sulphuric acid alone 1030 Pure sulphuric acid+l% aniline 843 Pure sulphur c'acid-l-1% iormol (30%).--. 107 Pure sulphuric acid+l0% of a ll-9% sulphuric acid extract of dissolved wood oils 28 Pure sulphuric acid-H0 of a 845% sulphuric acid extract of lved wood 0ils 77 2. Scaling baths. v The scaling solutions employed all contained 3.5 grams of gaseous HCl per 100 ccs.

The weight losses in grams per square meter per hour were for an average duration el- 24 hours 100 hours (a) Upon portions ofdraum iron tube pickled and cleaned A Pure hydrochloric acid alone 78. 2 Water+l0% of commercial scaling compound with a bimis oi araenious anhydride 2.80 6.0 Water+10% of commercial scaling compound with a basis of formol 0. 405 0. 602 Pure hydrochloric acid+1% of a 7-10% hydrochloric acid extract of dissolved wood oils 0. 501

The weight losses in grams square meter per hour were for an average duration of- (b) Upon crude sheet of pure aluminium for industrial apparatus A.

24 hours 48 hours Pure hydrochloric acid alone 3. 99 4. 68 Water+l0% commercial scaling compound with a basis oi arsenious anhydride. 5. 88 17. 4 Water+10% of a commercial scaling pound with a basis oi formol 27. 2 13. 4 Pure hydrochloric midi-1% oi formol (30%) 10. 6 11.4 -Pure hydrochloric acid+l%.ot a 7-10% hydrochloric acid extract oi\ dissolved wood oils 0. 89 0. 96 Pure hydrochloric acid+10% of a 7-10% hydrochloric acid extract of dissolved wood oils. 0. 28 0. 17

(c) Upon crude zinc sheet 2 hours 48 hours Pure hydrochloric acid alone 800 Water+l0% oi commercial scaling compound with a basis of arsenious anhydride 2070 Weter+10% commercial scaling compound with basis of iorinol 930 Pure hydrochloric acid+1% formol (30%).- 900 Pure hydrochloric acid-+10% of a 1015% hydrochloric acid extract of dissolved wood oils 0.74 0.29

For pickling and scaling baths the results are substantially the same with the ordinary acids of commerce more or less charged with impurities.

It has moreover been observed that even in the presence of accelerating impurities like arsenious anhydride the wood oils or their extracts maintain practically the whole of their efllciency.

What I claim is:

1. A metal treating bath comprising a diluted mineral acid and as an inhibitor product preventing the attack of the 'metal itself a low proportion of crude wood spirit oils arising from the carbonization of wood.

2. A metal pickling bath comprising a diluted mineral acid and as an inhibitor product preventing the attack of the metal itself a low proportion of crude wood spirit oils arising from carbonization of wood. I

3. A. metal scaling bathcomprising a diluted mineral acid and as an inhibitor product preventing the attack of the metal itself a low proportion of crude wood spirit-oils arising from carbonization or wood.

venting the attack of the metal itself a low proportion of crude wood spirit oils arising from the carbonization of wood.

6. A metal treating bath comprising a diluted mineral acid and as an inhibitor product preventing the attack of the metal itself a low proportion of an aqueous extract of wood spirit oils. JACQUES EDOUARD JULIEN GEORGES MASCRE.