Abstract: Provided is a method for removing deposited solid residue from equipment used in the processing of (meth)acrylic acid or esters, including the steps of dissolving the solid residue in a cleaning solution comprising an organic carboxylic acid to produce a solid residue slurry; and removing the solid residue slurry from the equipment.

Abstract: This invention provides a process for reducing biacetyl in alpha-, beta-unsaturated carboxylic acid esters, particularly in acrylic or methacrylic (hereinafter “(meth)acrylic”) esters, which comprise low levels of weak acid.

Abstract: Provided is a method for removing deposited solid residue from equipment used in the processing of (meth)acrylic acid or esters, including the steps of dissolving the solid residue in a cleaning solution comprising an organic carboxylic acid to produce a solid residue slurry; and removing the solid residue slurry from the equipment.

Abstract: The present disclosure provides a composition and method for the preparation of N-oxyl hindered amine esters by contacting a compound of Formula (I), wherein R1 and R2 are independently an alkyl, with a compound of Formula (II), wherein R3 and R4 are independently an alkyl, and n is an integer from 3 to 10, in the presence of a catalyst and a solvent, wherein the catalyst comprises at least one of tin, lithium, zirconium, and hafnium.

Abstract: The present invention provides a method for reducing accumulation of solid materials when manufacturing a (meth)acrylic acid ester having low biacetyl content (less than 2 ppm) by adding an aromatic diamine under conditions which provide sufficient residence time and thorough mixing to react up to 100% by weight of the biacetyl in the crude (meth)acrylic acid ester stream, prior to separation and purification. A feedback method is also provided for reducing solids accumulation in the separation and purification equipment of such processes by measuring the biacetyl content and adjusting the aromatic diamine addition rate so that excess aromatic diamine can be minimized. A third embodiment provides a method for reversing an accumulation of solid materials during such processes, while still producing a (meth)acrylic acid ester having low biacetyl content (less than 2 ppm), by reducing or ceasing the addition rate of aromatic diamine for a period of time.

Abstract: This invention provides a process for reducing biacetyl in alpha-, beta-unsaturated carboxylic acid esters, particularly in acrylic or methacrylic (hereinafter “(meth)acrylic”) esters, which comprise low levels of weak acid.