US3452038A - Certain bis(benzothiazole) compounds - Google Patents

Description

United States Patent 3,452,038 CERTAIN BIS(BENZOTHIAZOLE) COMPOUNDS Donald Richard Randall, Heaton Mersey, Stockport, and

Donald Kearey Howard, Levenshulme, England, assignors to Geigy Chemical Corporation, Greenburgh, N.Y., a corporation of Delaware No Drawing. Filed Aug. 12, 1965, Ser. No. 479,344 Claims priority, application Great Britain, Aug. 14, 1964, 33,366/ 64 Int. Cl. C07d 55/04; C23f 11/14, 11/10 US. Cl. 260-308 7 Claims ABSTRACT OF THE DISCLOSURE New bis-benzotriazole compounds are disclosed which have the following structure:

wherein X is (a) methylene which is substituted with one or two C alkyl groups, or C alkylene which is unsubstituted or substituted with 1 or more C alkyl groups, (b) a lzl-cycloalkyl containing at least five carbon atoms, (c) carbonyl, (d) sulfonyl, (e) oxygen, or (f) sulfur. These compounds, as well as those in which X is unsubstituted methylene or a chemical bond, are useful for inhibiting the tarnishing or corrosion of metals and the metal-induced deterioration of functional materials.

the formula NH NH I or with :5'-methylene-bis-benzotriazole, of the formula NH NH II or with a bis-benzotriazole compound of the formula Na -Q NH \NH/ III- wherein X represents (a) a divalent straight chain alkylene bridging group containing from one to six carbon atoms in the chain and being substituted with from one or two alkyl groups containing each from one to four carbon atoms where the alkylene group contains only one carbon atom, or being unsubstituted or substituted with at least one alkyl group containing from one to four carbon atoms where the alkylene group contains two or more carbon atoms; (b) lzl-cycloalkyl residue containing at least five carbon atoms; (c) a carbonyl group; ((1) a sulfonyl group; or (f) a sulfur atom.

Preferably X, as defined under (a) and being alkyl-substituted, bears as substituents from one to four alkyl groups each containing from one to four carbon atoms.

-In this specification and the appended claims, the term metallic surface" is used generically for both metal and metal alloy surfaces; corrosion-inhibiting is used generically for inhibiting corrosion as well as tarnishing.

If the bridging group X of Formula III represents an alkylene group, it contains from one to six carbon atoms; if one or more alkyl substituents are present in the alkylene group, the substituent may be a methyl, ethyl, npropyl, iso-propyl, n-butyl or iso-butyl group. Examples of alkylene bridging groups X include ethylene, n-propylene, n-butylene, n-amylene, n-hexylene, methyl-methylene, dimethyl-methylene, ethyl-methylene, diethyl-methylene, propyl-methylene, dipropyl-methylene-, n-butyl-methylene, di-n-butyl-methylene, 1 methyl-ethylene, 1,2 dimethylethylene, l-ethyl-ethylene, 1,2-ethyl-ethylene, l-npropylethylene, 1,2-n-propyl-ethylene, l-n-butyl-ethylene, 1,2 n-butyl-ethylene, 1,1-dimethyl-ethylene, 1,1-diethylethylene, 1,1 diethyl-ethylene, 1,l-di-n-propyl-ethylene, 1,1-di-n-butyl-ethylene, 1,1,2-trimethyl-ethylene or 1,1,2,2- tetramethyl-ethylene.

The process according to the invention is carried out in practice in a number of ways. Firstly, the metallic surface can be treated with a solution containing one or several bis-benzotriazole compounds of Formulas I, II and/or III. A solution containing the bis-benzotriazole compound or compounds in a proportion in the range of from 0.001% by weight to saturation may be used, but a solution containing from 0.01% to 5%, and particularly containing from 0.1% to 1%, by weight of the bis-benzotriazole compound, calculated on the weight of the solution, is preferred. The bis-benzotriazole compounds of Formulas I, II and III are sparingly soluble in water or other aqueous media, and organic solvents, especially oxygenated hydrocarbon compounds, can be used, for example acetone and other dialkyl ketones, isopropanol and other alkanols, 2-methoxy-ethanol and other al'koxy-al- 'kanols, or ethylene glycol or other alkylene-or dial'kyleneglycols, depending on the nature of the bis-benzotriazole compound, the concentration desired and the mode of treatment of the metallic surface with the solution. Other organic solvents, for example, trichlorethylene, can also be used where appropriate.

The metallic surface may be treated with the solution in any convenient manner. For instance, the surface can be dipped into or passed through the solution containing the bis-benzotriazole compound. The surface can also be treated by padding with absorbent material soaked in the solution, or by spraying the surface with an atomized mist of the solution.

Other methods of carrying out the process according to the invention include condensing the vapor of one or several of the bis-benzotriazole compounds of Formulas I, II and/or III on the metallic surface; enclosing or otherwise wrapping the metal object bearing the surface to be protected in wrapping material impregnated with one or several of the bis-benzotriazole compounds of Formulas I, II and/or III; applying one or several of the said hisbenzotriazole compounds in an abrasive or non-abrasive polish composition to the metallic surface; and incorporating one or several of the said bis-benzotriazole compounds in other compositions, for example anti-freeze or coolant formulations, or in functional fluids, for example synthetic lubricants or polymeric formulations, which are normally applied to, or are used in the presence of, a metallic surface.

A first, preferred mode of carrying out the process of the invention in practice, comprises flushing the metallic surface to be protected with a solution of one or several bis-benzotriazole derivatives of Formulas I, II and/or III preferably containing from 0.01% to 5%, and optimally from 0.1% to 1.0% by weight of the said bis-benzotriazole derivatives, calculated on the total weight of the solution, in a suitable solvent at an elevated temperature,

preferably a temperature within the range of from 60 to 100 C., and then allowing the treated metallic surface to dry in air or heating it to remove by evaporation any solvent remaining on the surface.

Another mode of carrying out the process of the invention in practice, comprises packing the surface of the metallic surface to be protected in wrapping material, for example, tissue paper imregnated with one or several bisbenzotriazole derivatives of Formulas I, II and/ or III. The wrapping material may be impregnated by soaking in a solution containing from 0.1% up to 5% by weight of the said bis-benzotriazole derivative, calculated on the weight of the solution.

A third mode of carrying out the process of the invention comprises moving or suspending the surface of the metallic surface in an atmosphere saturated with the vapor of one or several bis-benzotriazole derivatives of the Formulas I, H and/or III so as to expose said surface to the action of said atmosphere. The vapor is conveniently maintained at 85 C. and the metallic object may be chilled prior to being moved into the vapor to facilitate rapid condensation of the latter on the metallic surface to be protected.

A further mode of carrying out the process of the invention in practice comprises treating the surface of the metallic surface with a non-abrasive wax or polish containing one or several bis-benzotriazole derivatives of Formulas I, II and/or III. The wax or polish preferably contains between 0.1% and by weight of the said hisbenzotriazole derivative or derivatives. If solid wax is used, the bis-benzotriazole derivatives can be stirred into the molten wax and the mixture subsequently cast into a convenient form; if a liquid wax is used, the bis-benzotriazole derivatives can be added as a solution in a solvent Which is compatible with the liquid base of the wax.

A fifth mode of carrying out the process of the invention in practice comprises treating the metallic surface with a suspension of an abrasive material suspended in a liquid or soft solid medium and containng one or several bisbenzotriazole derivatives of Formulas I, II and/or III. Preferably the amount of bis-benzotriazole derivatives in such suspension is Within the range of from 0.01% to 5% and optimally within the range of from 0.1% to 1.0% by weight, calculated on the weight of the aforesaid medium.

The bis-'benzotriazole derivatives of Formulas I, II and III possess useful corrosion-inhibiting properties when applied to metallic surfaces, particularly to surfaces of copper, copper alloys, cadmium, or cadmium alloys. The bisbenzotriazole derivatives of Formulas I, II and III can be used, for example, to inhibit corrosion of a metallic surface exposed to an atmosphere comprising sulfur dioxide, hydrogen sulfide or ammonia or other corrosive gaseous constituent; for example, brass or other copper alloys may be treated with a benzotriazole derivative or derivatives of Formulas I, II and/or III in accordance with the process of the invention, to inhibit stress corrosion cracking due to exposure to sulfur dioxide.

According to a second aspect of the present invention, there are provided bis-benzotriazoles of the formula Nrr \NH/ 111 appearance of the surfaces. The said bis-benzotriazole derivatives are also valuable metal deactivators, particularly copper deactivators, when comprised in functional materials susceptible to deterioration of function in contact with the metal; such materials include functional fluids, and the said bis-benzotriazole derivatives when included in functional fluids for use at high temperatures, for example in high temperature synthetic lubricants.

According to a third aspect of the present invention, there are provided corrosion-inhibiting compositions for application to a metallic surface, and particularly to a copper or copper alloy surface, containing, as corrosion-inhibiting agent a bis-benzotriazole derivative or derivatives of Formulas I, II and/ or III.

The concentration of inhibitors in the corrosion-inhibiting compositions according to the invention is preferably within the range of from 0.01% to 5.0% and more preferably within the range of from 0.1% to 1.0% by weight based on the total weight of the composition, the concentration of the inhibitor varying according to the composition containing the inhibitor.

According to a fourth aspect, the present invention also provides a functional material per se susceptible to deterioration of function in contact with a metal, particularly copper or a copper alloy, which has been rendered less susceptible by comprising, as metal deactivator, a bis-benzotriazole derivative of Formulas I, II and/or III.

The conventration of inhibitors in the composition in the functional material is preferably within the range of from 0.001% to 0.5% and more preferably within the range of from 0.001% to 0.01% by weight based on the total weight of the functional material.

The compounds of Formulas I, II and III may also be advantageously used in metal or metal alloy protecting compositions or in functional materials in conjunction with other inhibitors, especially with inhibitors effective for the protection of ferrous metals.

Bis-benzotriazole, of Formula I, is produced by reacting 3:3'z4:4-tetraaminodiphenyl with nitrous acid or with a compound capable of forming nitrous acid under the conditions of the reaction, in the stoichiometric amounts required to diazotize only two of the four amino groups. The 3:3':4:4'-tetraaminodiphenyl may be treated, for example, with a mixture of an alkali metal nitrite and an inorganic acid. If desired, the reaction may be carried out under conditions similar to a conventional diazotization method, for example by treatment at a controlled temperature with an aqueous mixture of an alkali metal nitrite and hydrochloric acid, acetic acid or other inorganic or organic acid. The desired bis-triazole of Formula I is then formed by simultaneous elimination of two molecules of water under the diazotization conditions.

3:3:4:4'-tetraaminodiphenyl is produced, for instance, by reduction of 3 3'-dinitro-4:4'-diaminodiphenyl. The reduction can be carried out by treating the 3:3'-dinitro- 4:4'-diaminodiphenyl with molecular hydrogen in the presence of a cataylst; the hydrogenation cataylst can be, for example, Raney nickel. The reduction can be carried out in practice by contacting 3:3-dinitro-4:4'-diaminodiphenyl with a hydrogen-generating mixture, for instance with hydrochloric acid and iron or tin.

The 3z3'-dinitro-4:4-diaminodiphenyl is, in turn, produced by nitration of 4:4'-diaminodiphenyl. The nitration is carried out by reaction with nitric acid by a conventional method. Preferably the amino groups of the 4:4- diaminodiphenyl are protected during the nitration by conversion, for instance, into acetylamino or other acylamino groups. The conversion of the amino groups may be effected by reacting 4:4-diaminodiphenyl with the corresponding acid anyhdride or acylhalide, and after the nitration has been carried out, the amino group can be regenerated by hydroylsis, for example, with an aqueous solution of an alkali metal hydroxide.

5:5'-methylene-bis-benzotriazole of Formula II is produced by reacting 3 :3':4:4'-tetraaminodiphenylmethanc of the formula with nitrous acid or with a compound capable of forming nitrous acid under the conditions of the reaction in the stoichiometric amounts required to diazotize only two of the four amino groups. The 3:3':4:4-tetraaminodiphenylmethane is treated, for example, with a mixture of an alkali metal nitrite and an inorganic or organic acid. If desired, the reaction is carried out under conditions similar to a conventional diazotization method, for example, by treatment at a controlled temperature with an aqueous mixture of an alkali metal nitrite and hydrochloric acid, acetic acid or other inorganic or organic acid. The desired 5:S'-methylene-bis-benzotriazole is then formed by simultaneous elimination of two molecules of water under diazotization conditions.

The 3:3:4:4'-tetraaminodiphenylmethane is produced for instance, by reduction of 3:3-dinitro-4:4-diaminodiphenylmethane. The reduction is carried out by treating the 3:3'-dinitro-4:4-diaminodiphenylrnethane with molecular hydrogen in the presence of a catalyst; the hydrogenation catalyst can be, for example, Raney nickel. The reduction is carried out in practice by contacting the 3:3- dinitro-4:4'-diaminodiphenylmethane with a hydrogengenerating mixture, for instance with hydrochloric acid and iron or tin.

The 3:3-dinitro-4:4'-diaminodiphenylmethane is, in turn, produced by nitration of 4:4'-diaminodiphenylmethane. The nitration is carried out by reaction with nitric acid by a conventional method. Preferably the amino groups of the 4:4'-diaminodiphenylmethane are protected during the nitration by conversion, for example, into acetylamino or other acylamino groups. The conversion of the amino groups can be effected by reacting 4:4'- diaminodiphenylmethane with the corresponding acid anhydride or acyl halide, and after the nitration has been carried out, the amino groups can be regenerated by hydrolysis, for instance with an aqueous solution of an alkali metal hydroxide.

Alternatively, 3:3 dinitro-4:4'-diaminodiphenylmethane can be produced by rearrangement of N,N-methylenebis-o-nitroaniline of the formula NO: OzN

The rearrangement is preferably carried out initially in the presence of excess concentrated hydrochloric acid at a moderate temperature, for example, a temperature within the range of from 20 to 55 C. and subsequently at a higher temperature, for example, a temperature within the range of from 60 to 100 C. in the presence of gaseous hydrogen chloride. The 3:3'-dinitro-4:4-diaminodiphenylmethane product is isolated and purified by con ventional methods. The 3:3- dinitro-4:4'-diaminodiphenylmethane is then converted to 5:5'-methylene-bisbenzotriazole by the procedure described above.

The N,N'-methylene-bis-o-nitroaniline is, in turn, produced for example, by condensing two molecules of o-nitroaniline with one molecule of formaldehyde in an organic solvent, for instance methylated spirits, at an elevated temperature. The product is isolated by conventional methods such as distillation, and can be further purified, for example by recrystallization techniques.

Bis-benzotriazole derivatives of Formula III are produced by reacting a 3z3':4:4'-tetraaminodiphenyl derivative of the formula wherein X has the same meaning as in Formula III, with nitrous acid or with a compound capable of forming nitrous acid under the conditions of the reaction, in the stoichiometric amounts required to diazotize only two of the four amino groups. The 3:3:4:4'-tetraaminodipheny1 derivative can be treated, for example, with a mixture of an alkali metal nitrite and an inorganic or organic acid. If desired, the reaction can be carried out under conditions similar to a conventional diazotization method, for example, by treatment at a controlled temperature with an aqueous mixture of an alkali metal nitrite and hydrochloric acid, acetic acid or other inorganic or organic acid. The desired bis-benzotriazole derivative of Formula III is then formed by simultaneous elimination of two molecules of water under the diazotization conditions.

The 3:3:4:4'-tetraaminodiphenyl derivative of Formula VI is produced, for instance, by reduction of the corresponding 3:3-dinitro-4:4-diaminodiphenyl derivative of the formula NO: VII

wherein X has the same meaning as in Formula III.

The reduction iscarried out by treating the 3:3'-dinitro-4:4'-diaminodiphenyl derivative with molecular hydrogen in the presence of a catalyst; the hydrogenation catalyst can be, for example, Raney nickel. The reduction can also be carried out in practice by contacting the 3:3'-dinitro-4:4'-diaminodiphenyl derivative with a hydrogen-generating mixture, for instance with hydrochloric acid and iron or tin.

The 3:3'-dinitro-4:4'-diaminodiphenyl derivative is in turn, produced by nitration of the corresponding 4:4'-diamino-diphenyl derivative with nitric acid by a conventional method. Preferably, the amino groups of the 4:4- diaminodiphenyl derivatives are protected during the nitration by conversion, for example, to acetylamino or other acylamino groups. The conversion of the amino groups is effected by reacting the 4:4'-diaminodiphenyl derivative with the corresponding acid anhydride or acyl halide, and, after the nitration has been effected, regenerating the amino groups by hydrolysis, for instance with an aqueous solution of an alkali metal hydroxide.

Particular examples of bis-benzotriazole derivatives falling under Formula III can also 'be obtained by slightly modified methods. For instance, bis-(benzotriazolyl-S) ketone of the formula can be produced by nitrating 4:4'-dichlorobenzophenone using, for instance, fuming nitric acid at a low temperature, for example a temperature Within the range of from -10 to +10 C. and reacting the resulting 4:4'- dichloro-3:3-dinitrobenzophenone with ammonia, preferably in a closed vessel and at an elevated temperature, for example a temperature Within the range of from to 300 C. and preferably in the presence of an organic solvent, for instance ethanol, to produce 4:4'- diamino-3:3'-dinitrobenzophenone, if desired, purifying the product by recrystallization, for example, from pyridine; hydrogenating the 4:4'-diarnino-3:3-dinitro-benzophenone in the presence of a conventional hydrogenation catalyst, for example, Raney nickel, and preferably in an organic solvent, e.g. dioxan, removing the catalyst, and thereafter saturating the reaction mixture with gaseous hydrogen chloride to produce the tetrahydrochloride of 3:3'-4:4'-tetraaminobenzophenone having the formula and reacting the tetrahydrochloride with a diazotizing agent, e.g. sodium nitrite in an aqueous medium, in such stoichiometric proportions as to diazotize only two of the four amino groups, to form the desired bis(benzotriazolyl-S ketone of Formula VIII.

Bis-(benzotriazolyl-S)ketone can also be produced by the controlled oxidation of the bis-(benzotriazolyl)methane of Formula II. Similarly, bis-'(benzotriazolyl-5)sulfone can be produced by the controlled oxidation of bis (b enzotriazolyl-S sulfur.

The following examples further illustrate the present invention. Parts by weight shown therein bear the same relation to parts by volume as do kilograms to litres. Percentages and parts are expressed by weight unless otherwise stated.

EXAMPLE 1 5-methylene-bis-benzotriazole (A) 4:4-diacetamino-3 3-dinitrodiphenylmethane.- 562 parts of acetic anhydride were added to a solution of 496 parts of 4:4'-diaminodiphenylmethane in 496 parts by volume of benzene at 30 to 35 C. over a period of 3 hours. The mixture was then stirred at the same temperature for a further period of 1 /2 hours before being poured into an excess of cold water. The solid product formed was filtered ott, recrystallised from glacial acetic acid and dried in a vacuum oven. 596 parts of 4:4-diacetaminodiphenylmethane, having melting point 236 C. were obtained, representing a yield of 84.5% theoretical.

(B) 4:4 diacetamino-3:3'-dinitrodiphenylmethane.- 282.4 parts of 4:4-diacetaminodiphenylmethane were added a little at a time, With stirring, over a period of 30 minutes, to a mixture of 900.3 parts of 70% nitric acid and 1531.5 parts of acetic anhydride at a temperature of 50 C. The nitration mixture was then stirred at 50 C. for a further period of 1 /2 hours and then allowed to cool and stand at room temperature overnight. The precipitated reaction product was filtered off, washed with water and oven-dried. In this way 144 parts of 4:4-diacetamino 3:3'-dinitrodiphenylmethane were produced, having melting point 264 C. representing a yield of 38.6% theoretical.

(C) 4:4 diamino 3:3 dinitrodiphenylmethane. A mixture of 144 parts of 4:4-diacetamino 3:3'-dinitrodiphenylmethane, 62 parts of sodium hydroxide, 93 parts by volume of water and 1000 parts by volume of 2- methoxyethanol were heated under reflux conditions for 15 minutes and then allowed to cool to room temperature. The orange-red crystalline product which separated was filtered ofl, washed well with water and oven-dried. In this Way 97.7 parts of 4:4-diamino 3:3-dinitrodiphenylmethane were obtained, having melting point 238 C., representing a yield of 87.7% theoretical.

(D) 3 :3 4 4-tetraaminodiphenylmethane.--97.7 parts of 4:4-diamino-3:3-dinitrodiphenylmethane dissolved in 500 parts by volume of dioxan were hydrogenated in the presence of Raney nickel in a rocking autoclave at a temperature of 100 C. under an initial pressure of hydrogen of 50 atmospheres. The reaction mixture was cooled and filtered to remove the catalyst. The dioxan solvent was removed by distillation under reduced pressure leaving a solid residue which the then washed with methanol. In this way 51 parts of 3:3':4:4'tetraaminodiphenylmethane were produced having melting-point 135 C., representing a yield of 65.9% theoretical.

(E) 5 :5 methylene-bis-benzotriazole.27.6 parts of sodium nitrite dissolved in 48 parts of water were added, with stirring, to a solution of 45.6 parts of 3 :3:4:4-tetraaminodiphenylmethane in 48 parts of glacial acetic acid and 120 parts of water. The temperature of the reaction mixture rose rapidly to 95 C. and on cooling the reac tion mixture, a brown solid separated which was filtered 01f, washed with Water and oven dried. In this way 40 parts of 5:5'-methylenebis-benzotriazole were obtained,

having melting point 153 C. (d.), representing a yield of 79.1% theoretical.

EXAMPLE 2 A specimen from the same bright acid dipped copper foil was immersed in one of each of the following solutions: 0.01% w./v. aqueous solution of benzotriazole; 0.01% w./v. aqueous solution of 5 :5'-methylene-bis benzotriazole (as produced in the procedure described in Example l); 0.01% w./v. solution of benzotriazole in industrial methylated spirits; 0.01% w./v. solution of 5:5- methylene-bis benzotriazole in industrial methylated spirits; 0.1% w./v. solution of benzotriazole in industrial methylated spirits; 0.1% w./v. solution of 5 :5-methylenebis-benzotriazole in industrial methylated spirits. The six immersed specimens were maintained at 65 C. for five minutes and they were then washed in distilled water and dried in hot air.

The resistance to tarnishing of the copper specimens was compared with that of a seventh specimen of the same acid-dipped, but otherwise untreated, copper foil as a control, by exposing the specimens to an atmosphere containing 10 parts per million by weight of hydrogen sulphide. The time taken for the onset of visible tarnish to occur was recorded as a measure of tarnish resistance.

The results are shown in the following Table 1:

TABLE 1.-Copper specimen Industrial methylated spirits solution of 5 :5 '-methylene-bis-benzotriazole (treated with 0.1% w./v.) 30

These results demonstrate that the compound having the Formula II protects copper against tarnishing and that the protective properties are superior to those offered by benzotriazole.

EXAMPLE 3 A specimen from the same sheet of cadmium foil Was immersed in one of the following solutions: 0.01% solution of 5:5 methylene-bis-benzotriazole in industrial methylated spirtis; 0.01% solution of 5 :5'-methylene-bisbenzotriazole in water. The two immersed specimens were maintained at 65 C. for five minutes and they were then washed in distilled water and dried in hot air.

The resistance to tarnishing of the cadmium specimens was compared with that of an untreated specimen of the same cadmium foil as a control by exposing the four specimens to an atmosphere containing 10 parts per million by weight of hydrogen sulphide. The time taken for the onset of visible tarnish to occur was recorded as a measured of tarnish resistance.

The results are given in the following Table 2:

TABLE 2.Cadmiurn specimen Time (in hours) Control 2 to 4 Treated with 0.01% aqueous 5:5'-methylene-'bisbenzotriazole Treated with 0.01% industrial methylated spirits solution of 5z5'-methylenebis-benzotriazole These results demonstrate the effectiveness of the compound of the invention having the Formula II as a tarnish inhibitor for cadmium.

EXAMPLE 4 Samples of bright acid dipped copper were polished with an aqueous isopropanol suspension of an abrasive material containing 84 parts of aqueous 40% isopropanol and 15 parts of a-alumina (abrasive) both with and without the addition of 0.3% weight/weight of 5:5'-methylenebis-benzotriazole. A sample of the same copper was also polished with a similar abrasive material containing 1% of benzotriazole. The polished specimens of copper were then tested for tarnish inhibition by exposure to an atmosphere containing 10 parts per million by weight of hydrogen sulphide. The time taken for the onset of visible tarnishing to occur was recorded as a measure of the tarnish resistance imparted to the copper surface by the polish used.

The results are shown in the following Table 3:

TABLE 3.Copper specimen Time (in minutes) Polished with a polishing medium not containing a tarnish inhibitor 5 Polished with a polishing medium containing 0.3%

w./w. 5:5'-methylene-bis-benzotriazole 13 Polished with a polishing medium containing 1% benzotriazole 17 These results clearly demonstrate the tarnish inhibiting properties imparted to a copper surface by polishing with a polishing medium containing the compound of the invention having the Formula II.

EXAMPLE 5 Bis-(benzotriazolyl-S) ketone (A) 4,4 dichloro 3,3 dinitrobenzophenone.65 parts of 4,4-dichlorobenzophenone were added over 3 hours to 390 parts by volume of fuming nitric acid ((1. 1.50) at 2 C. After stirring the reaction mixture at room temperature for one hour thereafter it was poured into excess iced Water and the solid product which was precipitated was filtered oil. In this way were obtained 82 parts (92.2%) of the dinitro compound M.P. 132 representing a yield of 92.2% theoretical.

(B) 4,4 diamino 3,3 dinitrobenzophenone-31.8 parts of 4,4 dichloro 3,3 dinitrobenzophenone were divided into equal quantities and each reacted with 2.1 parts of ammonia in 20 parts by volume of ethanol in sealed glass tubes at 150 to 200 C. for 8 hours. The

total yield of diamino compound having M.P. 287 C. isolated after recrystallisation from pyridine was 14 parts representing a yield of 49.7% of the theoretical.

(C) 3,3,4,4' tetraminobenzophenone tetra'hydrochloride-14 parts of 4,4'-diamino-3,3-dinitrobenzophenone were hydrogenated in 500 parts by volume of dioxan in the presence of Raney nickel. The filtered dioxan solution was then saturated with dry hydrogen chloride gas. The tetrahydrochloride of the tetramino compound Was filtered off.

(D) Bis (benzotriazolyl ketone.-The resulting moist tetrahydrochloride of tetraminobenzophenone was dissolved in 250 parts and treated at 5 with 12.6 parts of sodium nitrite dissolved in 100 parts of water. The yellowish-brown solid that separated was filtered off and reprecipitated from the alkaline solution by addition of hydrochloric acid to neutrality. Further purification was effected by treating the concentrated hydrochloric acid solution of the product with carbon, filtering and then neutralising with caustic soda solution. In this way were obtained 4.5 parts (36.8%) of the bis-benzotriazole, having M.P. 285-6 (d.).

EXAMPLE 6 Bis- (benzotriazolyl-S) ether (A) 4,4 diacetarninodiphenyl ether.450 parts of 4,4-diaminodiphenyl ether in 900 parts by volume of henzene were treated with 450 parts of acetic anhydride at 10 30 C. to 45 C. for 1 /2 hours. After this time the product was filtered, washed with ethanol and then dried to furnish 450 parts (70.5%) of 4,4-diacetamino diphenyl ether, having melting point 229 C.

Analysis-Calculated (C H N O C, 67.59%; H, 5.76%; N, 9.85%. Found: C, 67.45%; H, 5.50%; N, 9.96%.

(B) 4,4 diacetamino 3,3 dinitrodiphenyl ether. 284 parts of 4,4-diacetaminodiphenyl ether were added over a period of 15 minutes to a mixture of 1530 parts of acetic anhydride and 900 parts of 70% nitric acid and the reaction mixture kept at 30 C. for 1 hour thereafter. The yellow solid which separated during the time was filtered, washed with glacial acetic acid and then water. In this way were obtained 290 parts (77.5%) of the dinitro compound, having melting point 215 C.

Analysis-Calculated (C H N O C, 51.34%; H, 3.77%; N, 14.97%. Found: C, 51.19%; H, 3.79%; N 14.91%.

(C) 4,4 diamino 3,3 dinitrodiphenyl ether.156 parts of 4,4 diacetamino 3,3 dinitrophenyl ether dissolved in Z-methoxyethanol 1370 parts) were treated under reflux conditions with parts of sodium hydroxide dissolved in 119 parts of water for a period of 15 minutes. The solid formed Was filtered off, washed thoroughly with water and dried. In this manner were obtained 107 parts (89.5%) of the diaminodiphenyl ether, having melting point 174 to 176 C.

Analysis.-Calculated (C12H10N4O5): C, H, 3.47%; N, 19.30%. Found: C, 49.89%; H, 3.67%; N, 19.44%.

(D) 3,3 4,4 tetraaminodiphenyl ether.- parts of 4,4 -diamino 3,3 dinitrodiphenyl ether dissolved in 500 parts by volume of dioxan Were hydrogenated in the presence of a Raney nickel catalyst. After filtering the hydrogenated solution, the dioxan was removed by evaporation to provide 75 parts of the crude tetraamino compound, having melting point C. (94.5% yield). This product was used in the stage E without further purification.

Analysis.Calculated (C H O): C, 62.59%; H, 6.13%; N, 24.33%. Found: C, 62.68%; H, 6.12%; N, 23.49%.

To 46 parts of the crude 3,3,4,4-tetraaminodiphenyl ether suspended in 48 parts of glacial acetic acid and 120 parts of water were added 27.6 parts of sodium nitrite dissolved in 48 parts of water and the temperature allowed to rise freely with stirring. The oily product initially formed was replaced by a brown solid which was filtered, washed with water and purified by precipitation from its alkaline solution by the addition of hydrochloric acid until neutrality. In this way were obtained 49 parts (99.1%) of crude benzotriazole. Two recr-ystallisations from 2-methoxyethanol after carbon treatments provided the desired bisbenzotriazole as a light brown solid, having melting point 243 to 244 C.

Analysis.Calcd. (C H N O): C, 57.15%; H, 3.18%; N, 33.34%. Found: C, 56.94%; H, 3.38%; N, 33.08%.

EXAMPLE 7 Bis-(benzotriazolyl-S) sulphone (A) 4,4-dichloro-3,3'-dinitrodiphenylsulphone.--60.3 parts of 4,4-dichlorodiphenyl-sulphone were dissolved in 301 parts of concentrated sulphuric acid and then 301 parts of fuming nitric acid (d.1.50) added slowly keeping temperature at 20 to 40 C. initially, then at 80 C. to give a clear yellow solution from which 83 parts (substantially of theoretical yield 100%) of the dinitro compound, having melting point 202 C. separated on pouring on to water.

(B) 4,4-diamino-3,3-dinitrodiphenyl sulphone.-37.7 parts of 4,4-dichloro-3,3'-dinitrodiphenyl sulphone was treated with 6.8 parts of ammonia dissolved in ethanol at C. for 9 hours. The yellow crystalline product was filtered and washed thoroughly with water until the washings were chloride free. The product, having melting point 309 C. was obtained in almost quantitative yield.

(C) 3,3',4,4' tetraaminodiphenylsulphone tetrahydrochloride.30 parts of 4,4'-diamino-3,3'-dinitrodiphenyl sulphone dissolved in 500 parts by volume of dioxan were hydrogenated in the presence of a Raney nickel catalyst. The dioxan solution was then saturated with hydrogen chloride gas and the precipitated hydrochloride (38.8 parts) separated by filtration and washed with dioxan.

(D) Bis-(benzotriazolyl-S) sulphone.-38.8 parts of the tetrahydrochloride still moist with dioxan was dissolved in 200 parts of water, this aqueous solution filtered and treated at C. for minutes, and then at 80 C. for 5 minutes with 25 parts of sodium nitrite dissolved in 100 parts of water. The buff-coloured precipitate was filtered ofi, washed with water and dried. Purification was eifected firstly by neutralising an alkaline solution of the product after filtration and secondly by neutralising, with ammonia, a hydrochloric acid solution of the product obtained after filtering. In this way were obtained 9 parts (33.3%) of the bisbenzotriazole having melting point 300 C. (d.) as a cream coloured solid.

EXAMPLE 8 Bis- (benzotriazolyl-S) and dried to provide 2.3 parts (96%) of the 'bis-benzo-' tria-zole, having melting point 320 C. and the following elemental analysis by weight:

Analysis.-Calcd.: C, 56.67%; H, 3.97%; N, 33.06%. Found: C, 56.86%; H, 3.74%; N, 32.46%.

EXAMPLE 9 Bis-(benzotriazolyl-S) methane or 5 :5'-methylene bis-benzotriazole To 200 parts o-nitroaniline dissolved in 2000 parts by volume of industrial methylated spirits was added 100 parts 40% formaldehyde solution and after heating on a steam bath for a short time, 2000 parts by volume of liquid were removed by distillation under reduced pressure.

To 186 parts of the residue, having melting point 195 C. were added 1860 parts of concentrated hydrochloric acid and the mixture maintained at 30 C. to 40 C. and then at 80 to 90 C. with the passage of hydrogen chloride gas. The initial yellow crystalline product slowly dissolved to give an orange solution from which yellow crystals later separated (reaction time 3 /2 hours). These crystals were filtered oif, washed with concentrated hydrochloric acid and then digested with hot water to provide 126 parts of the required product (67.7% yield) as an orange-red solid having melting point 230 to 234 C.

The remaining procedure for converting the 4:4'-diamino-3:3'-dinitrophenyl methane to 5 :5'-methylene bis- 'benzotri'azole is the same as that described in Example 1, parts D and B.

We have observed that although 5:5'-methylene-bisbenzotriazole melts at 153 C. it re-solidifies and results at 240 C. Possibly, therefore this substance exists in two forms one of which is more thermodynamically stable.

The elemental analysis by weight for the higher-melting form is as follows:

Analysis.(on product with melting point 240 C.): Calcd. (C H N C, 62.37%; H, 4.04%; N, 33.59%. Found: C, 62.29%; H, 4.07%; N, 33.18%.

EXAMPLE l0 Bis- (benzotriazolyl-S -1 :2-ethane (A) 4,4-dinitrodibenzyl.274 parts of p-nitrotoluene and 464 parts of isoamyl formate dissolved in 250 parts by volume of toluene were added to a suspension of 272 parts of sodium ethoxide in 500 parts by volume of toluene at 0 to 2 C. over 2 hours. The mixture was then stirred for a further 21 hours at 0 to 5 C. and poured into water. In this way, 136 parts (50% yield) of the dinitro compound, having melting point 176 to 176.5 C. were obtained.

(B) 4,4-diaminodibenzyl.150 parts of 4,4'-dinitrodibenzyl dissolved in 500 parts by volume of dioxan were hydrogenated in the presence of a Raney nickel catalyst. The filtered dioxan solution was evaporated to dryness. The crude diamino compound, M.P. 136 C. was obtained in substantially quantitative yield.

(C) 4,4 diacetaminodibenzyl.The 116 parts of crude diamino compound was suspended in 400 parts by volume of benzene and treated with 118 parts of acetic anhydride at 40 to 50 C. for 3 hours. The solid product was separated by filtration and washed with a little acetic acid, then water and finally with benzene. In this way 127.5 parts of 4:4-diacetaminodibenzyl were obtained having melting point 272 C.

(D) 4: 4'-diacetamino-3 3'-dinitrodibenzyl.-A solution of 482 parts by volume of 70% nitric acid and 731.86 parts 'by volume of acetic anhydride was made up at 5 C., and 127.5 parts of 4:4-diacetaminodibenzyl added to this solution at 25 C. over a period of 15 minutes. The resulting mixture was then heated at 50 to 70 C. for a period of one and a half hours. On cooling the reaction mixture in ice, a small amount of solid material was precipitated and the remaining solid product was obtained by adding water to the reaction mixture and cooling in ice. In this way 29 parts of 4:4'-diacetamino-3:3'-dinitrodibenzyl were obtained having melting point 270 to 272 C. and having the following elemental analysis by weight:

AnaIysis.-Calcd. (C14H14N4O4): C, H, N, 14.5%. Found: C, 56.0%; H, 5.0%; N, 13.98%.

(E) 4:4-diamino-3:3'-dinitrodibenzyl.A mixture of 23 parts of 4:4-diacetamino-3:3-dinitrodibenzyl, 9.6 parts of caustic soda, 19 parts by volume of water and 200 parts by volume of 2-methoxyethanol was heated under refiuxconditions for 15 minutes. The reaction mixture was then cooled in ice and the red solid which precipitated from the cooled reaction mixture was separated by filtration and washed with water and then with cold 2-methoxyethanol. In this way, 15 parts of 4:4-diamino- 3:3'-dinitrodibenzyl were produced (representing a yield of 82.7% of the theoretical) having a melting point of 286 to 287 C.

(F) 3:3:4:4'-tetraaminodibenzyl.15 parts of 4:4- diamino-3:3'-dinitrodibenzyl dissolved in 250 parts by volume of dioxane were hydrogenated in the presence of a Raney nickel catalyst. After filtering the hydrogenated solution, the dioxane solvent was removed by evaporation to provide the crude tetraamino compound.

(G) Bis-(benzotriazolyl-S) 1:2 ethane.-The crude tetra-amino compound was dissolved in water, this aqueous solution filtered and treated at 5 C. for 10 minutes, and then at C. for 5 minutes with sodium nitrate dissolved in water. The precipitate so formed was filtered oif, washed with water and dried. Purification of the product was efiected firstly by neutralising an alkaline solution of the product after filtration, and secondly by neutralising with ammonia, a hydrochloric acid solution of the product obtained after filtering. In this way bis(benzotriazolyl-5)-l:Z-ethane was obtained.

EXAMPLE 1 1 Bis(benzotriazolyl-5 )-1 l-cyclohexane (A) 4,4-diaminodiphenyl-l,l-cyclohexane.-To 475 parts of aniline dissolved in 440 parts by volume of concentrated hydrochloric acid was added 250 parts cyclohexanone and 52 parts by volume of alcohol and the mixture was heated on a steam bath for 12 days. By filtering off the solid that separated on cooling, dissolving this in water and treating with excess alkali, 132.3 parts of the diamino compound having melting point 114 C. were obtained.

(B) 4,4 diacetaminodiphenyl-l,I-cyclohexane.-42.5 parts of the diaminodiphenylcyclohexane dissolved in 300 parts by volume of benzene were added 36 parts of acetic anhydride and the mixture kept at 40 to 50 C. for 3 hours. The product was separated by filtration and gave 55.2 parts (98.9%) of the diacetyl compounds having melting point 266 to 227 C.

(C) 4:4 diacetamino 3:3 dinitrodiphenyl 1:1- cyclohexane.The 4:4'-diacetamino-diphenyl-l l-cyclohexane was added to a mixture of 70% nitric acid and acetic anhydride at to C. and the mixture stirred at 40 to 50 C. for a period of 1% hours after the completion of the addition. Water, in small amounts, was added to the nitration mixture to facilitate the separation of the solid product. In this way the 4:4-diacetamino- 3 3'-dinitrodiphenyl-1 l-cyclohexane was obtained.

(D) 4:4-diamino 3:3 dinitrodiphenyl 1:1 cyclohexane.-To the 4 4-diacetamino-3 3'-dinitrodiphenyl- 1:1-cyclohexane suspended in Z-methoxyethanol was added sodium hydroxide dissolved in water, and the resulting mixture heated under reflux conditions for 15 minutes. The addition of excess water to the reaction mixture after cooling caused the separation of the 4:4- diamino-3 :3'-dinitrodiphenyl1 l-cyclohexane.

(E) 3:3':4:4' tetraaminodiphenyl-1:1-cyclohexane. The 4:4 diamino-3:3-dinitrodiphenyl-1:l-cyclohexane dissolved in dioxane was hydrogenated in the presence of a Raney nickel catalyst. After filtering the hydrogenated solution, the dioxane solvent was removed by evaporation to provide the crude tetraamino product.

(F) Bis (benzotriazolyl-5) 1:1 cyclohexane.The crude tetraamino compound was dissolved in water, this aqueous solution filtered and treated at 5 C. for minutes, and then at 80 C. for 5 minutes with sodium nitrite dissolved in water. The precipitate so formed was filtered ofl, washed with water, dried and purified in the manner described in Example 10, part G. In this way bis-(benzotriazolyl-S )-1:1-cyclohexane was obtained.

EXAMPLE 12 Bis (benzotriazolyl-S -2 2-propane (A) 4,4-diaminodiphenyl 2,2 propane.To 465.6 parts of aniline dissolved in 440 parts of concentrated hydrochloric acid were added 145 parts of acetone and 52 parts by volume of ethanol and the reactants heated under reflux conditions for 12 days. Distillation of the residue after neutralisation gave a fraction with alkali having boiling point 192213 C. per millimetre of mercury pressure in which on recrystallisation from methanol gave 33 parts of the diamino compound having melting point 132 C.

(B) 4,4'-diacetaminodiphenyl 2,2 propane.-To 33 parts of the diamino compound dissolved in 60 parts by volume benzene were added 29.9 parts of acetic anhydride and the mixture kept at 40 to 50 C. for 3 hours; at the end of this time the solid product was separated by filtration and dried. In this way were obtained 38 parts (84%) of the diacetyl compound, melting point 250 to 252 C.

(C) 4,4 diacetamino 3,3 dinitrodiphenyl 2,2- propane-38 parts of the 4,4'-diacetaminodiphenyl propane were added to a mixture of 55 parts of 70% nitric acid and 198 parts of acetic anhydride at 05 C. and the mixture kept at 40 to 50 C. for 1% hours after the completion of the addition. Water, in small amounts, was added to the orange coloured nitration mixture to facilitate the separation of the product. In this way were obtained 26 parts (55.6%) of the dinitro compound having a melting point 190 C.

(D) 4,4 diamino-3,3'-dinitrodiphenyl-2,2-propane.- To 26 parts of 4,4 diacetamino 3,3 dinitrodiphenyl propane suspended in 400 parts by volume of 20 methoxyethanol were added 8.4 parts of sodium hydroxide dissolved in 11.5 parts of water and the mixture refluxed for 15 minutes. The addition of excess water to the reaction mixture after cooling caused the separation of the diaminodinitrodiphenylpropane as an orange solid, having melting point 214 C. The yield was 14 parts (66%).

(E) 3,3'-4,4-tetraaminodiphenyl-2,2-propane (in progress).14 parts of the diaminodinitrodiphenylpropane were hydrogenated in a 250 parts by volume of dioxan solvent in the presence of a Raney nickel catalyst. After filtering the hydrogenated solution, the dioxane solvent was removed by evaporation to provide 11.35 parts of the crude tetraamino compound.

(F) Bis-(benzotriazolyl-S)-2:2-propane.-The crude tetraamino compound was dissolved in water, this aqueous solution filtered and treated at 50 C. for 10 minutes, and then at C. for 5 minutes with sodium nitrate dissolved in water. The precipitate so formed was filtered ofi, washed with water, dried and purified in the manner described in Example 10, part G. In this way bis- (benzotriazolyl-S)-2:2-propane was obtained.

EXAMPLE 13 A specimen from the same bright acid-dipped copper foil was immersed in one of each of the following solutions:

0.01%, 0.1%, 0.5% weight/volume aqueous solution of benzotriazole;

0.01% weight/volume solution of bis-(benzotriazolyl-S) ketone in a mixture of parts of water and 10 parts of methylated spirits;

0.01% weight/volume solution of bis-benzotriazole in a mixture of 90 parts of water and 10 parts of methylated spirits;

0.01% weight/volume aqueous solution of 5 :5-methylene-bis-benzotriazole;

0.01% weight/volume aqueous solution of bis-(benzotriazolyl-S) ether.

The seven immersed specimens were maintained at 65 to 70 C. for two minutes and were then removed and dried in an oven at C., the tarnish so produced being of a uniform golden/ brown colour.

The resistance to tarnishing of the copper specimens was compared with that of an eighth specimen of the same acid-dipped but otherwise untreated copper foil as a control. The times indicated in the following Table 4 are the times at which the first sign of tarnish occurred.

TABLE 4.fiSolution in which copper specimen was immersed Time (minutes) The results summarized in Table 4 clearly demonstrate the improved resistance of copper to tarnishing at an elevated temperature when treated by a process of the present invention, compared with untreated copper and copper treated with benzotn'azole.

EXAMPLE 14 (A) Samples of bright acid dipped copper were polished with a water emulsifiable polish containing 0.2% weight/ weight of bis-benzotriazole, 5 :5-methylene bis-benzotriazole, bis-(benzotriazolyl-S)ketone and bis-(benzotriazolyl-S) ether. A sample of the same copper was also polished with the same water emulsifiable polish containing no bis-benzotriazole compound. The water emulsifiable soap consisted of 25 parts of red iron oxide (jewellers rouge), 1 part of hydroxymethyl cellulose, as gelling agent, 13.1 parts of soap consisting of 4.5 parts of triethanolamine and 8.6 parts of stearic acid, 3.2 parts of glycerol and 56.7 parts of water. The polished specimens were then tested for tarnish inhibition by exposing the speci- 10 parts per million by weight of hydrogen sulfide. The time taken for the onset of visible tranish to occur was recorded as a measure of tarnish resistance.

The results are shown in the following table:

mens to an atmosphere containing 10 parts per million 5 gggz i Tune (mmutes;

1 hide. The time taken for the "7" by Welght 9 hydrogein P (1) Brs-(benzotnazolyl)methane (treated with onset of visible tarnishing to occur was recorded as a 25% 15 measure of the tarnish resistance imparted to the copper (ii) Bis (benzotriazolynmethane (treated with surface by the pollsh used. 10 5 0% 25 The results are summarised in the following Table 5. 5 Bis fi ghggzfigggf igggfi ggg ga gfl TABLE 5.-Active ingredient of polish with which 2.5%)

copper specimen was treated (iv) Bis (benzotriazolyl)ether (treated with Time (minutes) 15 50%) 25 control 2 (v) Benzotriazole (treated with 2.5%) 10 Bisbenzotriazole (02%) 3 (vi) Benzotriazole (treated with 5.0%) 10 y n w n r 3 These results clearly demonstrate the improved protec- 3/ ketone 3 tion aiforded by the compositions of the present invention BiS-(bGHZOtIiaZO1YI-5) ether 3 compared with compositions containing benzotriazole. These results demonstrate the improved resistance to E A L 1 $5 3 5 3: ggggf g i pollshed with Specimens of copper foil were immersed in one of each (B) Samples of bright acid dipped copper were polished of h followmg lut1omz with a polish consisting of an aqueous isopropanol sus- Q. 001% welght/volume of 9 water pension of an abrasive material and also containing a (n) welght/Volume bls'(benzomazol.yl'5)' 0.2% weight/weight of 5:5-methylene-bis-benzotriazole i m water the remammg Procedure being as and 0.2% weight/weight of bis-(benzotriazolyl-S) ether. descmied m Example The results are Shown m the A sample of the same copper was also polished with the followmg table: same polish but containing no bis-benzotriazole compound. Copper specimen: Time (mins.) The copper samples were tested for tarnish resistance as Control 2 describe-d in Example 14A. (i) Treated with 0.01% benzotriazole 20 The results are summarised in the following Table 6. (ii) Treated with 0.01% bis-(benzotriazolyl-5)- Active ingredient of polish: Time (minutes) 1:2'ethane 30 Control 2 These results demonstrate the improved protection Bis-(benzotriazolyl-S) ether 6 aiforded by the above composition of the invention com- 5 :5 -methylene-bis-benzotriazole 8 pared with a composition containing benzotriazole. These results clearly demonstrate the improved resist- EXAMPLE 17 ance to sulphide tarnishing of copper specimens treated Synthetic ester-based lubricant compositions were pro- Wlth polishes of the present mventlon' duced and subjected to the Pratt and Whitney Type II EXAMPLE 15 oxidation-corrosion test with the iron and copper-protect- A specimen from the same bright acid dipped copper ing additives given in column 1 in the amounts (Weight foil was immersed in one of each of the following solupercent) given in column 2 of the table below. The base tions: fluid was trimethylol propane tripelargonate and each (i) 2.5% weight/volume of bis-(benzotriazolyl-5)- test was carried out for 48 hours at 425 F. with air at methane, in industrial methylated spirits the rate of 5 liters per hour and in the presence of copper (ii) 5.0% weight/volume of bis-(benzotriazolyl-5)- and steel. methane in industrial methylated spirits 50 The results are shown in the following table; the sludge (iii) 2.5 weight/volume of bis-(benzotriazolyl-5)- formation is expressed in mg; and the weight change of ether in industrial methylated spirits the specimens as mg./cm.

Percent Weight change Percent viscosity of specimens by weight increase at; Sludge Additive of additive 100 F. (mg) Cu Steel Dioctyldiphenyl-arni ne 4 52.58 0.3 2. 201 +0. 007 magenta- 0.: 64 0 Dioctyl diphenyl-amine+ 0 1 b1s-(benzotnazolyl-5)- J 31.80 0 0. 218 O. 015 methane.

(iv) 5.0% weight/volume of bis-(benzotriazolyl-5)- ether in industrial methylated spirits (v) 2.5 weight/volume of benzotriazole in industrial methylated spirits (vi) 5.0% weight/ volume of benzotriazole in industrial methylated spirits.

The six immersed specimens were maintained at 65 C. for two minutes and then washed in distilled water and dried in hot air.

The resistance to tarnishing of the copper specimens was compared with that of a tenth specimen of the same aciddipped, but otherwise untreated, copper foil as a control,

EXAMPLE 18 1 kg. of tissue paper is immersed in a 0.01% w./v. aqueous solution of 5 :5'-methylene-bis-benzotriazole, withdrawn from the solution and air-dried.

1 kg. of Wrapping paper is treated in the same manner.

by exposing the specimens to an atmosphere containing The resulting materials can be used for wrapping metal 17 articles or articles possessing metallic surfaces which require protection from corrosion and tarnishing.

We claim: 1. A bis-benzotriazole compound having the formula carbon atom, or being unsubstituted or substituted with 1 at least one alkyl group containing from one to four carbon atoms where the alkylene group contains two or more carbon atoms; (b) a 1: l-cycloalkyl residue containing five or six carbon atoms; (c) a carbonyl group; (d)

a sulfonyl group; (e) an oxygen atom; or (f) a sulfr atom.

. Bis-(benzotriazolyl-S) ether.

. Bis-(benzotriazolyl-S 1:2-ethane.

. Bis-(benzotriazolyl-S) ketone.

. Bis-(benzotriazolyl-S) sulfone.

. Bis-(benzotriazolyl-5)-1z l-cyclohexane.

. Bis- (benzotriazolyl-S -2 2-propane.

References Cited UNITED STATES PATENTS 5/1965 Carboni 260-30 r ALTON D. ROLLINS, Primary Examiner. 0

US. Cl. X.R.