BIS-(ALKYLSALICYLIDENE)ETHYLENE OR PHENYLENE DIAMINES AND TRANSITION METAL COMPLEXES THEREOF

Abstract: Preparation of N,N'-bis(alkylsalicylidene)ethylene or phenylene diamines, and transition metal complexes thereof, particularly copper, and their use as an additive to diesel fuel to reduce soot formation in diesel exhaust.

Description: BIS-(ALKYLSALICYLIDENE)ETHYLENE OR PHENYLENE DIAMINES AND TRANSITION METAL COMPLEXES THEREOF BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to novel N,N'- bis(alkyl salicylidene)ethylene or phenylene diamines and the transition metal complexes thereof, particularly Cu, Mn and Fe and the use of the complexes as an additive to diesel fuels. 2. Description of the Related Art The use of various metal compounds, particularly transition metal compounds such as compounds of manganese, lead, copper, zinc, cobalt and nickel, to name a few, in fuels to reduce soot formation and improve combustion properties of the fuel is known. U.S. Patent No. 4,673,412 teaches an oil-soluble, transition metal complex of a Mannich base and an oxime wherein the molar ratio of I:II is from about 1:10 to about 10:1 are useful in association with diesel fuels or fuel oils which give good storage stability and at the same time effectively reduce the ignition temperatures for soot particulates. The transition metal complexes of the N,N'- bis(alkylsalicylidene) ethylene or phenylene diamines according to the present invention are useful as additives in diesel fuel to reduce soot formation in diesel exhaust in the absence of mannich bases. SUMMARY OF THE INVENTION It has been surprisingly discovered that the transition metal complexes of N, N' - bis(alkylsalicylidene) ethylene or phenylene diamines are effective additives in fuels, especially diesel fuel, in reducing the soot content of the exhaust from the combustion of fuels containing the complexes. The N,N'- bis(alkylsalicylidene)ethylene or phenylene diamines according to the invention have the formula I C ID wherein R 1 is hydrogen or an alkyl group having from 1 to about 10 carbon atoms; R 2 is an alkyl group having from 1 to about 25 carbon atoms; R 3 is -CH 2 CH 2 - or and x and y are integers from 1 to 3, preferably 1. R χ is preferably hydrogen or methyl while R 2 is preferably an alkyl group having about 8 to about 15 carbon atoms. The total number of carbon atoms in the R 1 and R 2 groups should be sufficient to render the transition metal complexes thereof soluble in a diesel fuel such as kerosene. As a practical matter the total number of carbon atoms in the R 1 and R 2 groups will range from about 8 to about 50, preferably about 8 to about 30. The transition metal complexes of the compounds of formula I have the formula II and III I O C I I I wherein R λ and R 2 , x and y are as defined above and M is a transition metal preferably Cu, Mn or Fe, with Cu being most preferred. DESCRIPTION OF THE PREFERRED EMBODIMENTS Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term "about". The N,N'-bis(alkylsalicylidene)ethylenediamines according to the invention are made by reacting alkyl substituted salicylaldehydes or alkyl substituted 2- hydroxyacetophenones with ethylenediamine in the presence of an acid catalyst such as para-toluenesulfonic acid and a solvent which serves as a reaction solvent and forms an azeotrope with water to effect the removal of the water of reaction such as toluene. The alkyl substituted salicylaldehydes can be made by the method taught in U.S. patent No. 4,638,096, the entire contents of which are incorporated herein by reference. The alkyl substituted acetophenones can be made by the method of British Patent GB 1,458,695, the entire contents of which are incorporated herein by reference. The transition metal complexes of the N,N'-bis(alkylsalicylidene)ethylenediamines according to the invention can be made by dissolving an N,N'- bis(alkylsalicylidene)ethylenediamine in an aliphatic or aromatic kerosene, such as, preferably, Escaid® 110, a trademark product of Exxon-U.S. An aqueous solution of a water soluble salt of the transition metal and ammonium hydroxide is then added to the kerosene solution and the combined liquid phases are stirred together for 2 hours at room temperature after which the 2 liquid phases are allowed to separate. The kerosene phase, which contains the metal complex, is then separated. The transition metal complex is added to a diesel fuel or fuel oil in an amount to reduce soot formation, particularly in diesel exhaust, generally in an amount to provide up to about 200 ppm of the transition metal, preferably less than about 100 ppm, i.e. about 5_0 to about 100 ppm The following examples are meant to illustrate but not limit the invention. Example 1 Preparation of N, '-bis(5-dodβcylsalicylidene)ethylenediamine Dodecylsalicylaldehyde (557 g, 93% pure, 1.8 moles), ethylene diamine (54 g, 0.9 moles), para-toluenesulfonic acid hydrate (3.6 g, 0.02 moles), and toluene (1 liter) were combined in a 3-liter, 3-neck round bottom flask equipped with an overhead stirrer, a Dean-Stark trap, and a heating mantel. There was a slight exotherm (40 degrees C) upon combining the starting materials. The reaction was then heated to reflux, accompanied by vigorous stirring. After 2.5 hours, 32 ml of water were collected in the Dean- Stark trap and the reaction allowed to cool. The reaction was poured into a large separatory funnel and washed twice with 2% sodium bicarbonate (300 mis) and twice with water (300 mis) . The toluene was then removed under reduced pressure (rotoevaporation, 2 mbar/ 70 °C, 3 hours) to yield 557 g of the final product. IR and NMR showed only a trace of starting aldehyde (<1%) . Example 2 Preparation of N,N'-bis(5-nonylsalicylidene)ethylenediamine The procedure of Example 1 was followed using nonylsalicylaldehyde (560 g, 93% pure, 2.1 moles), and ethylenediamine ( 63 g, 1.05 moles) to yield 555 g of final product. Example 3 Preparation of N,N'-bis(2-hydroxy-5-nonyl-α- methylbenzylidene)ethylenediamine The procedure of Example 1 was followed using 5-nonyl- hydroxyacetophenone (631 q, 83% pure, 2 moles) and ethylenediamine (60 g, 1 mole) to yield ca. 600 g of final product. Example 4 Preparation of the Copper Complex of N,N'-bis(5-dodecylsalicylidene)ethylenediamine N,N'-bis(5-dodecylsalicylidene)ethylenediamine (236g, ca. 93% pure, 0.35 moles) was dissolved in 258 g of Escaid® 110 at 60 °C in a 2-liter round bottom flask. An aqueous solution of copper sulfate (500 g water; 85.6 g of CuS0 4 - 5H 2 0) and concentrated ammonium hydroxide (72 g of 30% in water) were added to the flask. The solution was stirred for 2 hours at room temperature using an overhead stirrer and the phases allowed to split overnight. In order to obtain a good phase split an additional 129 g of Escaid® 110 was added. The organic layer was separated and washed twice with 50 mis water. The organic solution was placed on a rotoevaporator at 20 mbar/ 70 °C for 2 hours to remove trace amounts of water. The loaded reagent in Escaid® 110 and the aqueous phase were analyzed for copper. Loaded reagent in Escaid® 110 : 32,200 ug Cu/g Aqueous phase : 3,530 ug Cu/g Example 5 Preparation of the Copper Complex of N,N'-bis(5-nonylsalicylidene)ethylenediamine N,N'-bis(5-nonylsalicylidene)ethylenediamine (236 g, ca. 93% pure) was dissolved in 258 g of Escaid® 110 at 60 °C in a 2-liter round bottom flask. An aqueous solution of copper sulfate ( 500 g water; 85.6 g of CuSO 4 -5H 2 0) and concentrated ammonium hydroxide (72 g of 30% in water) were added to the flask. The solution was stirred for 2 hours at room temperature using an overhead stirrer. The aqueous layer no longer possessed the indicative blue color, so an additional 100 ml of the CuS0 4 solution was added. The organic layer was separated and washed twice with 50 mis water. The organic solution was placed on a rotoevaporator at 20 mbar/ 70 °C for 2 hours to remove trace amounts of water. The loaded reagent in Escaid® 110 and the aqueous phase were analyzed for copper. Loaded reagent in Escaid® 110 : 42,400 ug Cu/g Aqueous phase : 5,200 ug Cu/g Example 6 Preparation of the Copper Complex of N, '-bis(2-hydroxy-5-nony1-α- methylbenzylidene)ethylenediamine N , N - b i s ( 2 - h y d r o x y - 5 - n o n y l - α - methylbenzylidene)ethylenediamine (268 g, ca. 83% pure) was dissolved in 258 g of Escaid 110 at 60 °C in a 2-liter round bottom flask. An aqueous solution of copper sulfate (500 g water; 85.6 g of CuSO 4 -5H 2 0) and concentrated ammonium hydroxide (72 g of 30% in water) were added to the flask. The solution was stirred for 2 hours at room temperature using an overhead stirrer. The phases were allowed to separate overnight. The organic layer was separated and washed twice with 50 mis water. The organic solution was placed on a rotoevaporator at 20 mbar/ 70 °C for 2 hours to remove trace amounts of water. The loaded reagent in Escaid® 110 and the aqueous phase were analyzed for copper. Loaded reagent in Escaid® 110 : 41,400 ug Cu/g Aqueous phase : 363 ug Cu/g

Claims: What is claimed is: 1. A compound of the formula I wherein R is hydrogen or an alkyl group having from 1 to about 10; R 2 is an alkyl group having from 1 up to about 25 carbon atoms, R 3 is CH 2 CH 2 or x and y are integers from 1 to 3, and the total number of carbon atoms in the R and R 2 groups is sufficient to render a transition metal complex of the compound soluble in a diesel fuel. 2. A compound as defined in claim 1 in which R χ is hydrogen or methyl; R 2 is an alkyl group having from about 8 to about 15 carbon atoms ' ; and x and y are 1. 3. A compound of claim 1 wherein R 2 is hydrogen. 4. A compound of claim 3 wherein R 2 is an octyl group. 5. A compound of claim 3 wherein R 2 is a nonyl group. 6. A compound of claim 3 wherein R 2 is a dodecyl group. 7. A compound of claim 1 wherein R χ is a methyl group. 8. A compound of claim 7 wherein R 2 is an octyl group. 9. A compound of claim 7 wherein R 2 is a nonyl group. 10. A compound of claim 7 wherein R 2 is a dodecyl group. 11. A transition metal complex of the compound defined in claim 1 in which the transition metal is selected from the group consisting of Cu, Mn and Fe. 12. N,N'-bis(5-dodecylsalicylidene)ethylenediamine 13. N,N'-bis(5-nonylsalicylidene)ethylenediamine 14. N , N ' - b i s ( 2 - h y d r o x y - 5 - n o n y l - α - methylbenzylidene)ethylenediamine 15. The copper complex of the compound defined in claim 10. 16. The copper complex of the compound defined in claim 11. 17. The copper complex of the compound defined in claim 12. 18. A diesel fuel or fuel oil containing the transition metal complex defined in claim 11. 19. A diesel fuel as defined in claim 18 wherein the transition metal is copper. 20. A diesel fuel as defined in claim 18 wherein the complex is present in an amount to provide up to about 200 ppm of the transition metal.

Inventors: KORDOSKY GARY A, SUDDERTH R BRANTLEY, KORDOSKY, GARY, A., SUDDERTH, R., BRANTLEY
Applicants: HENKEL CORP, HENKEL CORPORATION
Application year: 1995
Main classification: C07C251
IPC codes: C07C251, C10L1, C10L10