Fuel and related compositions – Liquid fuels – Containing organic -c
Reexamination Certificate
2002-06-18
2004-05-11
Medley, Margaret B. (Department: 1714)
Fuel and related compositions
Liquid fuels
Containing organic -c
C044S415000, C044S443000, C044S459000, C044S333000, C044S339000
Reexamination Certificate
active
06733551
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of improving the compatibility of a fuel additive composition. In particular, the present invention improves the compatibility of the fuel additive composition by blending together a fuel additive composition containing a Mannich condensation product, a hydrocarbyl-terminated poly(oxyalkylene) monool and a certain combination of a carboxylic acid and an anhydride.
2. Description of the Related Art
Mannich condensation products are known in the art as fuel additives for the prevention and control of engine deposits. For example, U.S. Pat. No. 4,231,759, issued Nov. 4, 1980 to Udelhofen et al., discloses reaction products obtained by the Mannich condensation of a high molecular weight alkyl-substituted hydroxyaromatic compound, an amine containing an amino group having at least one active hydrogen atom, and an aldehyde, such as formaldehyde. This patent further teaches that such Mannich condensation products are useful detergent additives in fuels for the control of deposits on carburetor surfaces and intake valves.
Generally, Mannich condensation products are utilized in combination with other fuel additive components. For example, polyolefins and polyether compounds are also well known in the art as fuel additives. It is not uncommon for the literature to refer to the enhanced benefits of the combination of two or more such fuel additives for the prevention and control of engine deposits.
U.S. Pat. No. 5,405,419, issued Apr. 11, 1995 to Ansari et al., discloses a fuel additive composition comprising (a) a fuel-soluble aliphatic hydrocarbyl-substituted amine having at least one basic nitrogen atom wherein the hydrocarbyl group has a number average molecular weight of about 700 to 3,000; (b) a polyolefin polymer of a C
2
to C
6
monolefin, wherein the polymer has a number average molecular weight of about 350 to 3,000; and (c) a hydrocarbyl-terminated poly(oxyalkylene) monool having an average molecular weight of about 500 to 5,000. This patent further teaches that fuel compositions containing these additives will generally contain about 50 to 500 ppm by weight of the aliphatic amine, about 50 to 1,000 ppm by weight of the polyolefin and about 50 to 1,000 ppm by weight of the poly(oxyalkylene) monool. This patent also discloses that fuel compositions containing 125 ppm each of aliphatic amine, polyolefin and poly(oxyalkylene) monool provide better deposit control performance than compositions containing 125 ppm of aliphatic amine plus 125 ppm of poly(oxyalkylene) monool.
In fuel additive applications, the presence of small amounts of low molecular weight amine in dispersant components such as the Mannich condensation product can lead to formulation incompatibilities (for example, with certain corrosion inhibitors or demulsifiers) and air sensitivity (for example, reaction with carbon dioxide in the air). For example, corrosion inhibitors are typically complex mixtures of organic acids of wide molecular weight range. These can react with trace amounts of low molecular weight amines in the Mannich component at room temperature to form insoluble salts and at higher temperatures to form insoluble amides. Formulation incompatibility and air sensitivity are manifested by formation of haze, floc, solids, and/or gelatinous material in the formulation over time. The incompatibility may occur in the absence of air. Consequently, the manufacturing process for amine dispersant type fuel additives may include a step to remove low molecular weight amines to low levels, or the compatibility issue may be addressed during formulation. However, the unique chemistry of Mannich condensation products must be considered with either approach. In particular, the chemical equilibrium can generate additional low molecular weight amines if the product is heated too much during the purification step or after a formulation has been prepared. Therefore, there is a need for either an economical process to reduce the unconsumed amine and the amine-formaldehyde intermediate to a low level after the Mannich reaction or a chemical scavenger that renders the water-soluble amine harmless to formulation compatibility and that reduces formulation air sensitivity.
U.S. Pat. No. 3,798,247 issued Mar. 19, 1974 to Piasek and Karil, discloses that the reaction under Mannich condensation conditions, like other chemical reactions, does not go to theoretical completion and some portion of the reactants, generally the amine, remains unreacted or only partially reacted as a coproduct. Unpurified products of Mannich processes also commonly contain small amounts of insoluble particle byproducts of the Mannich condensation reaction that appear to be the high molecular weight condensation product of formaldehyde and polyamines. The amine and amine byproducts lead to haze formation during storage and, in diesel oil formulations, to rapid buildup of diesel engine piston ring groove carbonaceous deposits and skirt varnish. The insoluble or borderline soluble byproducts are substantially incapable of removal by filtration and severely restrict product filtration rate. These drawbacks were overcome by adding long-chain carboxylic acids during the reaction to reduce the amount of solids formation from the Mannich reaction. This was thought to render the particulate polyamine-formaldehyde condensation product soluble through formation of amide-type links. In particular, oleic acid worked well at 0.1 to 0.3 mole/mole of alkylphenol. The quantity of unconsumed or partially reacted amine was not mentioned in the patent.
U.S. Pat. No. 4,334,085, issued Jun. 6, 1982 to Basalay and Udelhofen, discloses that Mannich condensation products can undergo transamination, and use this to solve the problem of byproduct amine-formaldehyde resin formation encountered in U.S. Pat. No. 3,798,247 eliminating the need for using a fatty acid. U.S. Pat. No. 4,334,085 defined transamination as the reaction of a Mannich adduct based on a single-nitrogen amine with a polyamine to exchange the polyamine for the single-nitrogen amine. The examples in this patent infer that the unconsumed amine and partially reacted amine discussed in U.S. Pat. No. 3,798,247 are not merely unconsumed, but must be in chemical equilibrium with the product of the Mannich condensation reaction. In Example 1 of U.S. Pat. No. 4,334,085, a Mannich condensation product is made from 0.5 moles of polyisobutylphenol, 1.0 mole of diethylamine and 1.1 moles of formaldehyde. To 0.05 moles of this product was added 0.05 moles of tetraethylenepentamine (TEPA) and then the mixture was heated to 155° C. while blowing with nitrogen. The TEPA replaced 80 to 95% of the diethylamine in the Mannich as the nitrogen stripped off the diethylamine made available by the equilibrium with the Mannich.
U.S. Pat. No. 5,360,460, issued Nov. 1, 1994 to Mozdzen et al., discloses a fuel additive composition comprising (A) an alkylene oxide condensate or the reaction product thereof and an alcohol, (B) a monocarboxylic fatty acid, and (C) a hydrocarbyl amine, or the reaction product thereof and an alkylene oxide. The fuel additive composition deals with cleaning of injection ports, lubricating a fuel line system in a diesel vehicle, and with minimizing corrosion in the fuel line system. However, the use of a Mannich condensation product is neither disclosed nor suggested.
SUMMARY OF THE INVENTION
We have discovered a novel method of improving the compatibility of a fuel additive composition by blending together a fuel additive composition containing a Mannich condensation product, a hydrocarbyl-terminated poly(oxyalkylene) monool, and a certain combination of a carboxylic acid and an anhydride.
Accordingly, the present invention provides a novel method of improving the compatibility of a fuel additive composition comprising blending together the following components:
a) a Mannich condensation product of (1) a high molecular weight alkyl-substituted hydroxyaromatic compound wherein the alkyl group has a number average molec
Carabell Kevin D.
Gray James A.
Chevron Oronite Company LLC
Lee Steven G. K.
Medley Margaret B.
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