Particulate Reduction in Gdi Engines Using Mannich Detergents

The present disclosure claims priority under 35 U.S.C § 119 to U.S. Provisional Application No. 63/658,076 filed on Jun. 10, 2024, which is incorporated herein by reference in its entirety.

The present disclosure relates to compositions and methods for emission particulate reductions in gasoline direct injection (GDI) engines using select Mannich detergents.

Gasoline direct injection (GDI) engines tend to produce higher levels of particulate emission when compared to port fuel injection (PFI) engines.

In one approach or embodiment, a method of reducing particulate emission in a gasoline direct injection engine is described herein. In one aspect of this embodiment, the method includes: combusting in the engine a gasoline composition including a Mannich detergent as an additive, wherein the Mannich detergent is produced by the reaction of hydrocarbyl-substituted phenol, an amine, and formaldehyde at a molar ratio of 1:1-2:2-3, and wherein the Mannich detergent is present in the gasoline composition at a concentration of about 40 to about 100 ppm.

In other approaches or embodiments, the method of the previous paragraph may be combined with one or more other features, steps, or embodiments in any combination. These other features, steps, or embodiments include one or more of the following: the molar ratio of the hydrocarbyl-substituted phenol, amine, and formaldehyde is 1:1-2:2; and/or wherein the molar ratio of the hydrocarbyl-substituted phenol, amine, and formaldehyde is 1:2:2; and/or wherein the hydrocarbyl substituent is derived from polyisobutylene and wherein at least 50 mol percent of polyisobutylene macromolecules have a tri-substituted alkene group, or wherein the hydrocarbyl substituent is derived from polyisobutylene and wherein at least 50 mol percent of polyisobutylene macromolecules have a tri-substituted alkene group and a tetra-substituted alkene group; and/or wherein the polyisobutylene having a tri-substituted alkene group has the following stereochemistry:

Wherein Ris a polymer chain and Ris —H or —CH; and/or wherein the polyisobutylene has less than 50 mol percent of terminal double bonds; and/or wherein the polyisobutylene includes one or more of a β-olefin isomer structure, a β-olefin structure, or a tetra-substituted olefin structure; and/or wherein the Mannich detergent is an oligomer; and/or wherein the hydrocarbyl substituent is derived from polyisobutylene having a number average molecular weight of about 400 to about 1500; and/or wherein at least 50 mol percent of polyisobutylene macromolecules have a tri-substituted alkene group, or wherein the hydrocarbyl substituent is derived from polyisobutylene and wherein at least 50 mol percent of polyisobutylene macromolecules have a tri-substituted alkene group and a tetra-substituted alkene group; and/or wherein the Mannich detergent is a compound having a structure of Formula I:

Wherein each Ris independently H or, together with the Ror Rmoiety in an adjacent —CH(R)NRRgroup, is a divalent —CH(R)— group; x is an integer of 1, 2 or 3; each Ris independently H or hydrocarbyl comprising 1 to 10 carbon atoms; each Rand Ris independently H, hydrocarbyl comprising 1 to 3000 carbon atoms which may be interrupted by one or more O, S and/or NRmoieties, or together with Rforms a divalent —CH(R)— group as defined above; y is an integer of 1, 2 or 3; each Ris independently hydrocarbyl comprising 1 to 3000 carbon atoms which may be interrupted by one or more O, S and/or NRmoieties; z is an integer of 0, 1 or 2; n is an integer of 1, 2 or 3; and Q is the hydrocarbyl substituent; and/or wherein, in at least 50% of the compounds of formula (I), said Q group is bonded to the central benzene ring such that it has the structure:

Wherein Ris a polymer chain, and together with the moiety —CH—C(CH) (CHCH)— through which it is attached to the central benzene ring, represents the Q group; and Ris —H or —CH; and/or wherein (1) any Q groups are para to an —ORgroup, (2) any —CH(R)NRRgroups are ortho to at least one —ORgroup, and/or (3) —R(if present) is ortho to at least one —ORgroup; and/or wherein the hydrocarbyl substituent Q is derived from polyisobutylene and wherein at least 50 mol percent of polyisobutylene macromolecules have a tri-substituted alkene group, or wherein the hydrocarbyl substituent Q is derived from polyisobutylene and wherein at least 50 mol percent of polyisobutylene macromolecules have a tri-substituted alkene group and a tetra-substituted alkene group; and/or wherein the Mannich detergent is a compound having a structure of Formula (Ia), (Ib), and/or (Ic):

wherein the —NRRgroup of Formula (Ia), (Ib), and/or (Ic) is —NH(CH)N(CH); and/or wherein the hydrocarbyl substituent Q is derived from polyisobutylene and wherein at least 50 mol percent of polyisobutylene macromolecules have a tri-substituted alkene group, or wherein the hydrocarbyl substituent is derived from polyisobutylene and wherein at least 50 mol percent of polyisobutylene macromolecules have a tri-substituted alkene group and a tetra-substituted alkene group; and/or wherein the amine is an alkylene polyamine; and/or wherein the alkylene polyamine is ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, or mixtures of alkylene polyamines of the formula HN-(A-NH—)H where A is divalent ethylene or propylene and n is an integer of from 1 to 10.

In yet another approach or embodiment, the use of any embodiment of this Summary is provided to provide improved particulate emissions reduction in GDI engines. In aspect, the use provides combusting in an engine a gasoline composition including a Mannich detergent as an additive, wherein the Mannich detergent is produced by the reaction of hydrocarbyl-substituted phenol, an amine, and formaldehyde at a molar ratio of 1:1-2:2-3, and wherein the Mannich detergent is present in the gasoline composition at a concentration of about 40 to about 100 ppm to provide improved particulate emissions.

The present disclosure relates to fuel additive packages, fuels, and methods of achieving emission particulate reductions in gasoline direct injection (GDI) engines using select Mannich detergents (e.g., reaction products of a hydrocarbyl-substituted hydroxyaromatic compound, an aldehyde, and an amine). In one approach or embodiment, the select Mannich detergents herein for emissions particulate reductions include one or more of the following characteristics: (i) certain molar ratios of the hydroxyaromatic compound, the amine, and the aldehyde; (ii) select oligomer structures; and/or (iii) certain isomeric forms of polyisobutylene substituents on the hydroxyaromatic compound.

For instance and in one approach, the select Mannich detergent(s) of the fuel additive packages, fuels, and methods herein for improved particulate emissions reduction in GDI engines include (i) a molar ratio of the hydrocarbyl-substituted hydroxyaromatic compound (e.g., a hydrocarbyl-substituted phenol) to amine (e.g., dimethylamino propylamine) to formaldehyde of 1:0.9-2.0:1.5-3.0 and, more preferably, 1:1-2:2-3, and even more preferably, 1:1-2:2, and most preferably, 1:2:2.

In other approaches or embodiments, the select Mannich detergent(s) of the fuel additive packages, fuels, and methods herein for improved particulate emissions reductions in GDI engines include (ii) one or more compounds or oligomers having structures defined by the below formulas, which are defined further herein:

In yet other approaches or embodiments, the select Mannich detergent(s) of the fuel additive packages, fuels, and methods herein for particulate emissions reductions includes (iii) certain isomeric forms of a polyisobutylene (PIB) substituent of the hydroxyaromatic group in which, in one approach, at least 50 mol % of the PIB macromolecules have a tri-substituted alkene group (e.g., a so-called conventional PIB). In another approach, the selected Mannich detergent of the compositions, fuels, or methods herein includes a Mannich reactant product having a isomeric forms of the polyisobutylene (PIB) substituent of the hydroxyaromatic comprising both (a) PIB macromolecules having a tri-substituted alkene group and (b) PIB macromolecules having a tetra-substituted alkene group, wherein the proportion of PIB macromolecules having both a tri-substituted and a tetra-substituted alkene group is at least 50 mol %, and wherein the Mannich reactant product and PIB substituent are subjected to conditions under which PIB macromolecules having a tetra-substituted alkene group will react to produce PIB macromolecules having a tri-substituted alkene group. Such PIB groups are referred to as conventional PIB, and Conventional PIB typically has less than 50 mol %, less than 40 mol %, less than 30 mol %, less than 20 mol %, or less than 10 mol % content of terminal double bonds.

In yet alternative approaches, the isomeric forms of the polyisobutylene (PIB) substituent may have greater than 50 mol %, greater than 60 mol %, greater than 70 mol %, greater than 80 mol %, or greater than 90 mol % content of terminal double bonds. In such form, this alternative PIB substituent is referred to as highly reactive PIB (e.g., “HR-PIB”). HR-PIB having a number average molecular weight ranging from about 800 to about 5000, as determined by GPC, may be suitable for use in embodiments of the present disclosure. Such HR-PIB is commercially available, or can be synthesized by the polymerization of isobutene in the presence of a non-chlorinated catalyst such as boron trifluoride, as described in U.S. Pat. No. 4,152,499 and/or U.S. Pat. No. 5,739,355. When used in the aforementioned thermal ene reaction, HR-PIB may lead to higher conversion rates in the reaction, as well as lower amounts of sediment formation, due to increased reactivity. A suitable method is described in U.S. Pat. No. 7,897,696.

In embodiments, a particular type of PIB has been developed for use in preparing lubricant and gasoline additives, namely PIB having an increased proportion of macromolecules in which the double bond is located at the end of the chain, to make the PIB more reactive. This can be achieved by using pure isobutene feedstock and a catalyst based on BF, as reported by Mach et al (Lubrication Science 11-2, February 1999 (11) pp 175-185). More recently, it has also been achieved using AlClin a form of complex with ether (Kostjuk et al, Journal of Polymer Science, Part A: Polymer Chemistry 2013, 51, 471-486).

The structural differences between the more reactive HR-PIB and the conventional PIB substituents herein, and the implications for reactivity, are summarised in by the following terms and shown in the chart below (Mach et al (Lubrication Science 11-2, February 1999 (11) pp 175-185)):

The structures indicated above are referred to herein using the following nomenclature:

PIBs containing a high proportion of exo groups (i.e. vinylidene end groups) are generally referred to as high reactive PIB (e.g., HR-PIB). On the other hand, PIBs containing a high proportion of tri, endo, and tetra groups are generally referred to as conventional PIB. In one approach, the select Mannich detergents herein may include a high proportion of conventional PIB-based Mannich reaction products. In alternative approaches, the select Mannich detergents herein may include a high proportion of HR-PIB-based Mannich reaction products.

Such PIB macromolecules are produced with select conditions, and said conditions comprise contacting the Mannich reactants and the PIB substituent with a source of protons, such as BF/HF. When using the approach with conventional PIB macromolecules, the PIB substituent is preferably one in which at least 60 mol % of the PIB macromolecules have a tetra-substituted alkene group, more preferably at least 70 mol %, more preferably still at least 80 mol %, and yet more preferably at least 90 mol %. Preferably, the tetra substituted alkene groups in the PIB macromolecules are located within or attached to a terminal C4 unit in the macromolecule. More preferably the PIB macromolecules suitable for the detergent compositions, fuels, and particulate emission reduction methods of the present disclosure are of the structure:

A preferred example of a Mannich detergent of the compositions, fuels, and methods herein is a product obtained or obtainable from a Mannich reaction between an aldehyde, an amine, and a select PIB-substituted hydroxyaromatic compound that has been prepared as described herein and having the noted PIB macromolecules. Such a PIB-substituted hydroxyaromatic reagent has been found to be enriched in compounds wherein the PIB substituent is bonded to the aromatic ring in the following manner:

Thus, the present disclosure provides a detergent obtained or obtainable from a Mannich reaction between the aldehyde, the amine, and the selected PIB-hydroxyaromatic compound wherein at least 70 mol % (such as at least 75 mol %, at least 80 mol %, at least 85 mol %, at least 90 mol % or at least 95 mol %) of the molecules has the structure depicted above.

In other approaches, the improved particulate emissions reductions of the Mannich detergents herein can be obtained using conventional PIB substituents prepared as follows and wherein the improved efficacy can be achieved by increasing the proportion of tri-PIB, i.e. the proportion of PIB wherein the alkene moiety appears at the end of the molecule and has the structure —CH—C(CH)═CHCH. Typically in this regard the tri group will have the following stereochemistry:

To prepare such a detergent having improved efficacy, PIB that is enriched in tri-PIB can be reacted with a reagent serving as a source of a group comprising a polar moiety, under conditions appropriate for the PIB to react with said reagent so as to form a compound in which the PIB is bonded to the group comprising a polar moiety.

As for the PIB that is enriched in tri-PIB, this can be prepared directly. For instance, polymerisation of isobutylene in hexane with an initiator such as HO, MeOH, tBuCl, TMPCl (2-chloro-2,4,4-trimethyl-pentane) or CumCl (cumyl chloride), in conjunction with EADC (EtAlCl) in the temperature range of −40 to 25° C. can be used to prepare a PIB product having around 70% tri-PIB and around 30% tetra-PIB, with negligible exo- and endo-PIB. (Dimitrov et al., (Macromolecules 2011, 44, 1831-40). Alternatively, PIB that is enriched in to some extent in tri-PIB can be prepared from conventional PIB or HR PIB, e.g. by exposing the PIB sample to a Lewis acid or Bronsted-Lowry (protic) acid.

In relation to both of these approaches, though, it is noteworthy that due to the preference in the art to use HR PIB (with its high levels of exo-PIB), as a general rule the preparation of PIB enriched in tri-PIB is specifically avoided, particularly when the PIB is envisaged for use in preparing a detergent additive. The consequential loss of exo-PIB is seen as undesirable.

In situations where PIB contains both tri-PIB and tetra-PIB, the effective proportion of tri-PIB can be increased by reacting the PIB with said reagent having a group comprising a polar moiety under conditions in which the tetra-PIB will react to produce tri-PIB. This enhances the effective proportion of tri-PIB in situ. Thus, tri-PIB can be formed readily from tetra-PIB under suitable conditions, e.g. in the presence of a source of protons. A mechanism for this process, following cation formation, has been described by Dimitrov et al. (Macromolecules 2011, 44, 1831-1840). That reaction pathway has been summarised by Kostjuk et al. (citation details noted above) in the scheme reproduced below, in connection with the formation of tri-substituted olefinic end groups during the EtAlCl(AlCl)-co-initiated cationic polymerisation of PIB.

In this regard, the present invention also relates to a method of preparing PIB that is highly enriched with tetra-PIB. Such a highly enriched PIB can advantageously be used as a precursor for PIB that is highly enriched in other isomeric forms.

For instance, PIB that is highly enriched in tetra-PIB can be used to prepare a PIB reagent that is highly enriched in tri-PIB, or (if different conditions are used) a PIB reagent that is highly enriched in exo-PIB. Alternatively, PIB that is highly enriched with tetra-PIB can be used to form tri-PIB in situ during the preparation of a detergent product. In this regard, the fact that the tetra-PIB can be efficiently reacted to produce other types of PIB in this way means that the high levels of tetra-PIB enrichment possible in accordance with the present invention can effectively be transferred to provide similar levels of tri- and exo-PIB enrichment.

PIB that is highly enriched with tetra-PIB can be prepared by subjecting a sample of PIB containing a high proportion of exo- and endo-PIB (such as a typical HR PIB) to double bond isomerisation in circumstances in which the back-biting step depicted in Scheme 1 above is inhibited. For instance, the PIB sample can be subjected to double bond isomerisation in a molecular sieve, wherein the molecular sieve limits the extent to which the macromolecules can adopt the conformation that is needed in order for this intramolecular cyclic reaction to occur.

As regards the mechanism for the formation of tetra-PIB in this regard, Dimitrov et al. (citation details noted above) have proposed the reaction pathway set out below. In this regard, the isomer labelled 4′ in the scheme below (i.e. one of the two tetra-PIB isomers) was reported to be most preferred.

In line with the scheme set out above, in the PIB that is enriched with tetra-PIB (and optionally also enriched with tri-PIB, as discussed above), the alkene group having the tetra structure in tetra-PIB should be located within or attached to a terminal C4 unit in the macromolecule, and typically has one of the two structures noted below, with the second structure usually being more preferred:

Also, for completeness it is to be noted that cation 1 in scheme 2 can be formed from both exo- and endo-PIB. This is illustrated by the following further reaction scheme:

As explained above, PIB that is highly enriched in tetra-PIB can advantageously be used, inter alia:

In case (3), the PIB that is highly enriched in tetra-PIB can be combined with a reagent having a group comprising a polar moiety under conditions where back-biting (see Scheme 1 above) can arise and indeed is promoted (e.g. protic conditions), thus favouring the production of tri-PIB. The more reactive tri-PIB reacts preferentially with said reagent, so as to form detergent compounds having a structure which, as discussed above, imparts altered thermal stability, and has improved detergent activity.

In case (1), similar conditions to those identified in case (3) may be used to encourage back-biting so as to produce tri-PIB. This approach might be preferable to the formation of tri-PIB in situ as in approach (3), in instances where the PIB enriched in tri-PIB is intended for use in an application wherein the presence of tetra-PIB may be undesirable for some reason.