Abstract: The invention relates to a process to separate linear 5-formylvalerate compound from a crude mixture comprising 5-formylvalerate compound and 2-, 3- and/or 4-formylvalerate compound by vacuum distillation, wherein the distillation is performed in the presence of a phenolic compound with a boiling point which is at least 10° C. higher than the boiling point of the 5-formylvalerate at 0.1-100 kPa.

Abstract: Process to separate a rhodium/phosphite ligand complex and free phosphite ligand from a hydroformylation mixture also containing high boiling hydroformylation compounds by contacting said mixture with a polymeric membrane, wherein said mixture is diluted with at least one diluent compound having a solubility parameter such that the absolute difference in relation to the solubiltity parameter of the polymeric membrane lies between 0 and 400{square root}{square root over (KJ/m3)} and the ratio of the molar volume of the phosphite ligand and said diluent compound is ≧1.5, to such an extent that the amount of high boiling compounds in said mixture is ≦50 wt. % (relative to the total amount of the mixture) and the amount of compounds with a molecular weight of between x ±200 is ≦20 wt. % (relative to the total amount of the mixture) whereby x is the cut-off of the membrane (g/mole).

Abstract: The invention relates to a process to separate linear 5-formylvalerate compound from a crude mixture comprising 5-formylvalerate compound and 2-, 3- and/or 4-formylvalerate compound by vacuum distillation, wherein the distillation is performed in the presence of a phenolic compound with a boiling point which is at least 10° C. higher than the boiling point of the 5-formylvalerate at 0.1-100 kPa.

Abstract: Process for the continuous preparation of an alkyl 5-formylvalerate by reacting an alkyl-3-pentenoate with carbon monoxide and hydrogen by hydroformylation using a catalyst system comprising rhodium or iridium and a multidentate organic phosphite ligand according to the general formula: in which n is 2-6, X is an n-valent organic bridging group, and in which the end groups R1-R2 are monovalent aryl groups, wherein the process is carried out in the presence of an acid compound having a pKa between 1 and 12 measured in water at 18° C.

Abstract: Process for the preparation of an aldehyde through hydroformylation of an unsaturated organic compound in the presence of a catalyst system comprising rhodium of iridium and a multidentate organic phosphite ligand, wherein a monodentate phosphine is present.The process according to the invention can advantageously be carried out for the preparation of methyl-5-formylvalerate, which is an intermediate product in the preparation of a caprolactam or adipic acid, which are in turn raw materials for the preparation of nylon-6 and nylon-6,6, respectively.