Abstract: A process for the manufacture of methyl methacrylate includes a process for separating the methyl methacrylate from certain impurities, at least one of which has a freezing point of greater than −50° C., by a fractional crystallisation process.

Abstract: An improved joint edge assembly, of the type used in the construction of concrete slabs, is disclosed. The assembly comprises a longitudinal joint rail, preferably of steel, which is supported off the ground by temporary formwork. The joint rail is secured to the formwork by mounting brackets. The joint rail comprises first and second joint edge members that are connected to each other by connectors with self-release elements. A plurality of studs extends downward and outward from each of the joint edge members into the concrete slabs provide a positive mechanical connection between the slab and the joint rail. As the concrete shrinks during hardening, the self-release elements of the connectors allow the joint to freely open. The joint edge assembly thus provides a self-releasing expandable joint between adjacent slab sections, and protects the edges of the adjacent slab sections from damage. A dowel aligner may also be integrated into the assembly, to allow proper positioning of dowels within the slab.

Abstract: A process for the removal of formaldehyde species from a liquid carboxylic acid or carboxylic acid ester stream which forms a two-phase mixture with water is disclosed which comprises the step of subjecting the liquid organic mixture to at least one liquid liquid extraction stage wherein water is used as an extractant to produce an organic phase stream which is substantially formaldehyde free and an aqueous phase stream which contains substantially all of the formaldehyde in the output streams from the liquid liquid extraction. The process is particularly useful for reducing the formaldehyde content of a methyl methacrylate product stream.