Use of at least one phenolic compound to stabilise ethylene copolymerisation reactions

A method of stabilizing radical ethylene copolymerization reactions for approximately 5 to 10 minutes, the method comprising using a phenolic compound with other comonomers, wherein the phenolic compound possesses a structure according to Formula (I):

• wherein:
• R1 represents:
• a hydrogen atom;
• a linear C1-C8 alkyl radical;
• a linear C1-C8 hydroxyalkyl radical;
• or
• a hydroxy group;
• R2, R3, R4 and R5, identical or different, represent:
• a hydrogen atom;
• a C1-C8 alkyl radical, linear or branched, optionally substituted by one or more hydroxy radicals;
• a C1-C8 alkoxy radical, linear or branched, optionally substituted by one or more hydroxy radicals;
• or
• a hydroxy group, and
• it being understood that R4 and R5 can together form a five- or six-member cycle comprising an oxygen atom;
• said cycle being substituted by a C1-C17 alkyl radical, linear or branched;
• wherein the other comonomers comprise unsaturated carboxylic acid esters (or their salts), and optionally at least one other comonomer selected from the group consisting of carboxylic acid anhydrides, vinyl esters, alpha-olefins, unsaturated carboxylic acids, derivatives of (meth)acrylic acid, vinyl ethers, aromatic vinyl compounds, carbon monoxide, and mixtures thereof;
• wherein the unsaturated carboxylic acid esters include a C1-C24 (meth)alkyl acrylate and a (meth)acrylate possessing an epoxy group;
• wherein the method further comprises performing the radical ethylene copolymerization reactions at a high pressure in the presence of one or more initiators,
• wherein the method further includes a step of introducing a reaction mixture comprising ethylene and the comonomers into a reactor with a residence time of 30 to approximately 50 seconds and does not include a step in which the comonomers are preheated prior to the introduction of said one or more initiators, and
• wherein the method limits the decomposition of the ethylene during the radical ethylene copolymerization reactions at the high pressure.