Already, biochemical and genetic studies are revealing pathways of fatty acid biosynthesis in oilseeds which could be exploited for modifying the existing seed oils to make them more industrially attractive [ 5 ].
STR3 Compounds based on other ruthenium analogs such as phosphorous Wittig-type reagents or diazomethane derivatives prepared by other methods also catalyze metathesis reactions. In another embodiment, the invention is a method of forming a polycycloolefin comprising the step of polymerizing an olefin with a catalyst in the presence of a peroxide as set forth above; decomposing the peroxide in the polymer to form reactive species of the peroxide; and using the reactive species to form crosslinks in the polymer.
The polymerization can be carried out in the absence of a solvent. Generally, these catalysts may be described by the formula STR6 wherein: A method according to claim 9, wherein L and L1 are trialkylphosphine ligands.
Alkyl peroxides such as t-butyl peroxide, including di-t-butyl peroxide, provide polymers with desirably high crosslink density.
M is Os or Ru; R and R1 are independently selected from hydrogen or a hydrocarbon selected from the group consisting of C1 -C20 alkyl, C2 -C20 alkenyl, C2 -C20 alkynyl, C2 -C20 alkoxycarbonyl, aryl, C1 -C20 carboxylate, C1 -C20 alkoxy, C2 -C20 alkenyloxy, C2 -C20 alkynyloxy and aryloxy; X and X1 are independently selected from any anionic ligand; and L and L1 are independently selected from any neutral electron donor.
Olefins are polymerized via a metathesis mechanism in the presence of a crosslinking agent and a catalyst. The orange solution was stirred at room temperature for 8 minutes under argon until it became highly viscous.
However, there are few limitations with natural oils still to be overcome, namely, the fact that in major seed oils such as sunflower, rapeseed, soybean and palm oil the main fatty acids have the carbon chain length ranging from C16 to C18 and lack functionalities that give them wider industrial application such as the hydroxy and the epoxy groups [ 4 ].
Meanwhile, Engine metathesis mechanism is being made with regard to the variation of the carbon chain length of these oleochemicals and the introduction of important functionalities using chemical manipulation methods [ 6 — 9 ].
These catalysts and methods for making them are disclosed in U. The resulting norbornene polymers can be end-capped and show polydispersities of 1.
Generally, in methods according to the present invention, the "modifier" or crosslinking agent is mixed with the monomer, e. Time to exotherm of the polymerization reaction is generally between about 5 minutes and 6 hours, at which time the viscosity of the mixture increases rapidly.
The amount of peroxide in the reaction mixture is preferably between 0. Preferably, L and L1 are trialkylphosphine ligands and at least one of the alkyl groups on the phosphine ligand may be a secondary alkyl or cycloalkyl group, especially P isopropyl 3, P cyclopentyl 3 and P cyclohexyl 3.
A method of forming a polycycloolefin comprising the steps of: The monomer polymerizes via a metathesis mechanism and then the crosslinking agent decomposes, e. Polymers having high density crosslinking are desirable for their improved mechanical strength and low gel swell.
Olefins may be cyclic e. Presented in this paper is an overview of the developments in olefin metathesis involving sunflower-based feedstocks and their potential application as raw materials for the chemical industry. As shown in Table I, discussed in greater detail below, polymers prepared according to the present invention been found to have dramatically increased solvent resistance compared to polymers prepared using the same ruthenium catalysts but without peroxide addition.
STR2 In this process, the metal halide and reducing agent components are separately mixed with the monomer.Lowering the Boiling Curve of Biodiesel by Metathesis Especially during the regeneration phase, fuel bedabbles the piston walls and is taken over into the engine oil.
Unlike fossil diesel fuel, biodiesel can not evaporate out of the engine oil because The mechanism of metathesis reactions was first described by Yves Chauvin in In.
The reaction mechanism operative in olefin metathesis has been and still is a challenging area of research. Here we contribute to the discussion showing that the actual mechanism is a balance of the title effects.
In particular, we show that the electronic and solvent effects evidenced by experimental studies can be easily counterbalanced by. Ignition (HCCI) engine experiments. The surrogate mechanism developed is the present study is based on the available PRF mixtures (n-heptane and iso-octane) mechanism of Buda et al.
 and on • Metathesis of benzyl radicals with n-heptane and iso-octane leading to toluene and alkyl radicals. Carbene Rotamer Switching Explains the Reverse Trans Effect in Forming the Grubbs Second-Generation Olefin Metathesis Catalyst.
Poly(alkyl methacrylate)-Grafted Polyolefins as Viscosity Modifiers for Engine Oil: A New Mechanism for Improved Performance. A combination of ring-opening metathesis polymerization, atom transfer radical polymerization of alkyl methacrylates, and hydrogenation was used to prepare the target materials.
Viscometric measurements. Olefins are polymerized via a metathesis mechanism in the presence of a crosslinking agent and a catalyst. Romp polymerization in the presence of peroxide crosslinking agents to form high-density crosslinked polymers - Google Patents Romp polymerization in the presence of peroxide crosslinking agents to form high-density .Download