METHOD FOR PRODUCING BUTADIENE BY OXIDATIVE DEHYDROGENATION OF N-BUTENES BY MONITORING THE PEROXIDE-CONTENT DURING PRODUCT PROCESSING

The invention relates to a method for producing butadiene from n-butenens, comprising the following steps: A) a feed gas flow (a) containing n-butenes is provided; B) the feed gas flow (a) containing n-butenes and an oxygen-containing 10 gas is fed to at least one dehydrogenation area and is oxidatively dehydrogenated from n-butenes to form butadiene; a product gas flow (b) containing butadiene, unreacted n-butenes, water vapour, oxygen, low-boiling point hydrocarbons, optionally carbon oxides and optionally inert gases is obtained; C) the product gas flow (b) is cooled and compressed in at least one 15 cooling step and at least one compression step, said product gas flow (b) being brought into contact with a coolant (4) supplied in the circuit; at least one condensate flow (c1) containing water and a gas flow (c2) containing butadiene, n-butenes, water vapour, oxygen, low-boiling point hydrocarbons, optionally carbon oxides and optionally inert gases is obtained; D) non-condensable and 20 low-boiling point gas component parts containing oxygen, low-boiling point hydrocarbons, optionally carbon oxides and optionally inert gases are separated from the gas flow (c2) by absorbing C4-hydrocarbons containing the butadiene and n-butenes in absorption means supplied in the circuit; an absorption agent flow charged with C4-hydrocarbons and the gas flow (d2) are obtained, and subsequently the C4-hydrocarbon is desorbed from the charged absorption agent flow; a C4-product gas flow is obtained; E) the C4-product flow (d1) is separated by extractive distillation using a selected solvent for butadiene in a butadiene and the material flow (e1) containing the selective solvent and a material flow (e2) containing n-butenes; F) the butadiene and the material flow (e1) containing the selective solvent is distilled in a material flow (f1) consisting essentially of the selective solvent and a material flow (f2) containing a butadiene; wherein the samples are taken in step C) from the coolant (4) supplied in the circuit and samples are taken in step D) from absorption means supplied in the circuit, the peroxide content being determined in the taken samples using iodometry, differential scanning calorimerty (DSC) or micro calorimerty. (Fig.1)