Fuel and related compositions – Liquid fuels – Organic nitrogen compound containing
Reexamination Certificate
2001-02-02
2004-10-05
Toomer, Cephia D. (Department: 1714)
Fuel and related compositions
Liquid fuels
Organic nitrogen compound containing
C044S424000, C564S336000
Reexamination Certificate
active
06800103
ABSTRACT:
TECHNICAL FIELD
This invention relates to novel Mannich base condensation products and fuel compositions comprising said Mannich products that are effective in controlling intake valve deposits and minimizing valve sticking in internal combustion engines.
BACKGROUND
Despite extensive prior research activities on Mannich base fuel additives carried out over the years, a need exists for Mannich base compositions having superior performance capabilities and superior physical properties. In particular, a most welcome contribution to the art would be the provision of Mannich base compositions that are highly effective in controlling intake valve deposits in internal combustion engines, that are capable of minimizing valve sticking under standard qualification test conditions, that require, and in many cases perform better with, smaller amounts of liquid carrier fluids than are conventionally used, and that provide all of these advantages at attractive competitive costs.
This invention is deemed to constitute such a contribution. The Mannich base additives of the present invention are more active in controlling and reducing intake valve deposits than some other Mannich base products. The Mannich products of the present invention also have lower viscosities compared to other Mannich products which provides additional benefits to the product.
SUMMARY OF THE INVENTION
This invention is based on the discovery that Mannich condensation products having superior performance characteristics and excellent physical properties can be formed by selection of certain amines and hydroxyaromatic compounds to be used in the condensation reaction and by using the reactants in specific proportions relative to each other to make pure compounds with minimal undesired byproducts, which may adversely impact the performance of the additives. Further, it has been discovered that by using a di-substituted hydroxyaromatic compound which has only one site for the Mannich reaction to occur, i.e., only one ortho- or para-position being unsubstituted, in combination with a secondary amine having only one hydrogen capable of entering into the Mannich reaction, products are obtained which are more effective at controlling intake valve deposits on an active/active basis compared to Mannich base products derived from a hydroxyaromatic compound having two or three reactive sites or Mannich base products derived from primary amines or amines having more than one active hydrogen. The term “active” when used to describe the Mannich reaction products means the total mass of products, regardless of chemical identity but not including solvent. Therefore, compounds of the present invention are more effective at controlling intake valve deposits than compounds derived from a hydroxyaromatic compound substituted in only one position, or containing a different amine, when both Mannich products contain equivalent amounts of amine-containing products. Also, the desired Mannich base products of the present invention can be made in higher yields compared to products made from a hydroxyaromatic compound substituted in only one position or one made from an amine having more than one reactive hydrogen.
Thus, in one of its embodiments this invention provides a Mannich product obtained by reacting a mixture of (i) at least one substituted hydroxyaromatic compound having on the ring both (a) an aliphatic hydrocarbyl substituent derived from a polyolefin having a number average molecular weight in the range of about 500 to about 3000, and (b) a C
1-4
alkyl; (ii) at least one secondary amine; and (iii) at least one aldehyde. In one embodiment, components (ii) and (iii) may be pre-reacted to form an intermediate prior to addition of (i). Preferred products of this type are formed by heating a mixture formed from (i), (ii) and (iii), at a temperature above about 40° C. at which a Mannich condensation reaction takes place.
Another embodiment of this invention is a fuel additive composition which comprises:
a) a Mannich product as described above, and
b) at least one liquid carrier or induction aid therefor, most preferably at least one poly(oxyalkylene) compound, having an average molecular weight in the range of about 500 to about 3000.
Still another embodiment includes fuels for spark ignition engines into which have been blended the various compositions of this invention described herein, and methods for minimizing or reducing intake valve deposits and/or minimizing or reducing intake valve sticking in an internal combustion engine by fueling and/or operating the engine with a fuel composition of this invention.
In additional preferred embodiments of this invention the Mannich product is obtained by reacting a di-substituted hydroxyaromatic compound in which the hydrocarbyl substituent (a) comprises polypropylene, polybutylene or an ethylene alpha-olefin copolymer having a number average molecular weight in the range of about 500 to about 3000 and a polydispersity in the range of about 1 to about 4, one or more secondary amines, and at least one aldehyde. Because of outstanding effectiveness in the control (i.e., reduction or minimization) of the weight of deposits formed on intake valves during engine operation, an especially preferred embodiment involves use of dibutyl amine as the secondary amine, formaldehyde or formalin as the aldehyde, and a molar ratio of the above substituted hydroxyaromatic compound to dibutyl amine to formaldehyde of 1:0.8-1.5:0.8-1.5, respectively. A more preferred molar ratio for these last-named reactants is 0.9 to 1.2 moles of the dibutyl amine and 0.9 to 1.2 moles of aldehyde per mole of the above di-substituted hydroxyaromatic compound. Such Mannich base reaction products have given superlative results in an extensive number of tests.
Other embodiments and features of this invention will become still further apparent from the ensuing description and appended claims.
DETAILED DESCRIPTION
Mannich Base Reaction Product
Representative di-substituted hydroxyaromatic compounds used in forming the Mannich base products of the present invention are represented by the following formula:
in which R is H, C
1-4
alkyl, or a hydrocarbyl substituent having a number average molecular weight in the range of about 500 to about 3000, with the proviso that one R is H, one R is a C
1-4
alkyl and one R is a hydrocarbyl substituent. It has been discovered that by using a substituted hydroxyaromatic compound which has only one site for the Mannich reaction to occur, i.e., only one ortho- or para-position being unsubstituted (i.e., where one R═H) in combination with a secondary amine, as defined herein, products are obtained that are very effective at reducing intake valve deposits. Further, the Mannich base products of the present invention can be made in higher yields compared to products made from a hydroxyaromatic compound substituted in only one position (for example, hydroxyaromatic compounds where one R is a hydrocarbyl substituent and two R's are H such as a hydrocarbyl-substituted phenol).
Representative hydrocarbyl substituents include polypropylene, polybutene, polyisobutylene, and ethylene alpha-olefin copolymers). Other similar long-chain hydrocarbyl substituents may also be used. Examples include copolymers of butylene and/or isobutylene and/or propylene, and one or more mono-olefinic comonomers copolymerizable therewith (e.g., ethylene, 1-pentene, 1-hexene, 1-octene, 1-decene, etc.) where the copolymer molecule contains at least 50% by weight, of butylene and/or isobutylene and/or propylene units. The comonomers polymerized with propylene or such butenes may be aliphatic and can also contain non-aliphatic groups, e.g., styrene, o-methylstyrene, p-methylstyrene, divinyl benzene and the like. Thus in any case the resulting polymers and copolymers used in forming the di-substituted hydroxyaromatic compound are substantially aliphatic hydrocarbon polymers. Polybutylene is preferred. Unless otherwise specified herein, the term “polybutylene” is used in a generic sense to include polymers made from “pure” o
Colucci William J.
Malfer Dennis J.
Noble Andrea T.
Sheets Roger M.
Ethyl Corporation
Rainear Dennis H.
Robinson Leah O.
Toomer Cephia D.
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