Catalysts suitable for decreasing the cold filter plugging point of middle distillates

Abstract

Ethylene copolymers with alpha-olefins utilizable as additives to increase the properties of middle distillates at low temperatures, obtainable by polymerization in the presence of catalysts comprising the reaction product between: 1) a bis-cyclopentadienyl derivative having the general formula: (Cp 1 Cp 2 )—M—(L 2 L 3 ) containing groups with oxygen bound to the transition metal, wherein M is a metal from the IIIb group to the IIb group or of the lanthanides series of the periodic table of the elements; 2) a co-catalyst chosen from alumoxanes or boranes.

1 . Ethylene copolymers with one or more alpha-olefins from 3 to 8 carbon atoms, utilizable as additives to improve the middle distillates properties at low temperatures, obtainable by polymerization of the monomers in the presence of catalysts comprising the reaction product among: 
 1) a bis-cyclopentadienyl having the general formula:    (CP 1 CP 2 )—M—(L 2 L 3 )  containing groups with oxygen bound to the transition metal, wherein    M is a metal from the IIIb group to the IIb group or of the lanthanides series of the periodic table;    Cp 1  and Cp 2 , equal to or different from each other, represent the following groups bound to M with delocalized π bonds, in particular with an eta bond 5 when the groups are chosen among: cyclopentadiene, indene, fluorene, or their derivatives substituted (in the case of indene and fluorene also by the hydrogenated phenilic ring (rings)) and with substituents both in the phenilic and cyclopentadienylic rings, also with heteroatoms; or with π bonds for instance in the case of cyclooctatriene; or said groups CP 1  CP 2  constrained with M by a bivalent linking bridge, for instance —R— type, wherein R is an alkylene, preferably from 1 to 4 carbon atoms, —Si(R′) 2 — wherein R′ is an alkyl from 1 to 10 C atoms, preferably from 1 to 6 carbon atoms; or an aryl optionally containing heteroatoms, such as O, N, or alkylaryl or arylalkyl from 7 to 20 carbon atoms;    L 2  or L 3 , equal to or different from each other represent an OR a  group wherein R a  is an aryl group, optionally the carbon atoms of the ring being substituted by heteroatoms, and optionally containing substituents for instance of alkylic type from 1 to 10 carbon atoms with      2) a co-catalyst selected among the compounds represented by the following formulas:    2a) alumoxane, having the general formula:    (Rb—Al—O) m ,  under the form of cyclic compound or under the form of linear polymeric compound having the formula R b (R b   13  Al—O) m  Al(R b ) 2 ;    alumoxane is generally a mixture of the two mentioned forms;    R b  is an alkylic group from 1 to 5 C atoms, preferably methyl,    m is an integer from 1 to 30, preferably from 4 to 20;    m′ is an integer from 3 to 20, preferably from 4 to 20;      2b) (L 1 —H) + (A)−
 wherein (A) − is a compatible non coordinate anion, preferably  
 (B Q q ) −   
 wherein L 1  is a neutral Lewis basis,  
 (L 1 —H) + is a Bronsted acid,  
 B is an element of the group from IIIa up to VIa of the Periodic Table with metalloidic characteristics, preferably boron, phosphor or arsenic in the valence 3 or 5, silicon, more preferably boron in the valence 3;  
 Q, equal to or different from each other, are selected from the following groups: hydrides, halides, alkyls, aryls optionally substituted, for instance with halogens, preferably F, alkoxides, aryloxides, dialkylamido, or R 0 COO − wherein R 0  has from 1 to 20 carbon atoms, with the proviso that Q can be equal to halide only once,  
 q is an integer equal to the valence of B plus 1.  
   
     
     
         2 . Ethylene copolymers with alpha-olefins according to    claim 1    wherein component 2 is component 2b).  
     
     
         3 . Ethylene copolymers with alpha-olefins according to    claim 2    wherein the molar ratio between component 2b) with respect to the amount of the metal of component 1 (metallocene) is comprised between (0.1-4):1 and preferably between (0.5-2.0): 1.  
     
     
         4 . Ethylene copolymers with alpha-olefins according to claims  2 - 3  wherein the compound 2b) has the general formula  
       (L 1 —H) + (B Q 4 ) −   wherein the meanings of L 1  and Q are indicated above, B is boron in the valence 3.    
     
     
         5 . Ethylene copolymers with alpha-olefins according to claims  1 - 4 , wherein the compounds 2b) are selected among substituted ammonium trialkyl salts, for instance triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tris (n-butyl) ammonium tetraphenylborate, trimethylammonium tetrakis(ptolyl)borate, tributylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis (2,4-dimethyphenyl) borate, tributylammonium tetrakis(3,5-dimethylphenyl)-borate, triethylammonium tetrakis (3,5-ditrifluoromethyl-phenyl)borate.  
     
     
         6 . Ethylene coplymers with alpha-olefins according to claims  1 - 5 , wherein the compounds 1) are derivatives of titanium, zirconium, vanadium, hafnium, chromium, lanthanum.  
     
     
         7 . Ethylene copolymers with alpha-olefins according to    claim 6    wherein the compounds 1) are titanium or Zr derivatives.  
     
     
         8 . Ethylene copolymers with alpha-olefins according to    claim 7   , wherein the compounds 1) are bis (eta 5 cyclopentadienyl) Zr diphenate; bis (eta 5 cyclopentadienyl) Zr 2,3, 6-trimethylphenate, bis tetramethylcyclopentadienyl Zr diphenate.  
     
     
         9 . Ethylene copolymers with alpha-olefins according to claims  1 - 8  characterized in that they have the inversions X 2  and/or X 4  lower than 0.02.  
     
     
         10 . Ethylene copolymers with alpha-olefins according to claims  2 - 9 , characterized in that they have a number of terminal ethenylidene or ethenyl unsaturations lower than 30%.  
     
     
         11 . Ethylene copolymers with alpha-olefins according to    claim 10   , characterized in that they have a number of terminal ethenylidene or ethenyl unsaturations lower than 20%.  
     
     
         12 . Use of the ethylene copolymers with alpha-olefins according to claims  1 - 11  as additives for middle distillates.  
     
     
         13 . Use of the ethylene copolymers with alpha-olefins according to claims  2 - 11  as additives for middle distillates.  
     
     
         14 . Use of the ethylene copolymers with alpha-olefins according to claims  12  or  13  wherein the amount of alpha-olefins is generally comprised between 15-60by weight, preferably between 20-55% by weight, more preferably 25-45%, the amount of conjugated diolefins is comprised between 0-10% by weight.  
     
     
         15 . Use of the ethylene copolymers with alpha-olefins according to claims  12 - 14 , characterized in that they are combined with other known cold flow improvers (CFI).  
     
     
         16 . Use of the ethylene copolymers with alpha-olefins according to    claim 15    wherein CFI are ethylvinylacetates, fumarates, acrylates, propionates, optionally in the presence of a third CFI selected from the nitrogen polar compounds.  
     
     
         17 . Use of the ethylene copolymers with alpha-olefins according to    claim 16   , wherein the ratios by weight between the copolymer, the known CFI and the nitrogen polar compound is the following: 10/1:10/1:10, preferably 10/1:5/1:5.  
     
     
         18 . Catalysts according to claims  1 - 8 .  
     
     
         19 . Catalysts according to claims  2 - 7 .