Abstract: A method is proposed for leakage monitoring in a tube bundle reactor (2) having a bundle of contact tubes (2) vertically arranged parallel to one another, through which a fluid reaction mixture is delivered, and through whose space (3) surrounding the contact tubes a liquid heat exchanger is delivered, and having one or more vent holes (4) for the liquid heat exchanger in the upper region of the tube bundle reactor (1), which connect the tube bundle reactor (1) to one or more equilibrating vessels (5, 6, 7) for the liquid heat exchanger, wherein at least one of the equilibrating vessels (5, 6, 7) for the liquid heat exchanger has a connecting line (8) for supplying the gas phase above the liquid level therein to an analysis device (9), which determines the composition of the supplied gas phase.

Abstract: The invention relates to a method for monitoring exothermic reactions in a reactor, in which one or more starting materials react exothermically to give at least one product, and at least one gas is present in the reactor during operation as intended or during a runaway, comprising the following process: A) measurement and storage of an initial temperature and an initial pressure in the reactor, B) calculation of the amount of products and starting materials present in the reactor from an energy balance, C) calculation of a maximum pressure raise that occurs on stepwise reaction of the amount of starting materials present, and D) calculation of a runaway pressure from the maximum pressure raise that occurs, calculated in step C), and the measured initial pressure stored in step A).

Abstract: The present invention relates to a process for performing catalyzed oxidation reactions of hydrocarbons over a catalyst disposed in a reactor, which comprises cooling the product gas stream of the catalyzed oxidation reaction immediately after it leaves the reaction zone of the reactor by feeding in a temperature-controlled gas stream which is fed in through at least one feed device into the region between lower reactor plate and outlet of the product gas stream.

Abstract: The invention relates to a process for recovering 3-aminomethyl-3,5,5-trim-ethylcyclohexylamine (isophoronediamine, IPDA) having a fractionally distilled cis/trans isomer ratio of at least 73/27. The process includes the following steps: a) providing IPDA in a cis/trans isomer ratio of <73/27; b) feeding IPDA into the middle region of a distillation column having internals and distilling the IPDA in this distillation column at a temperature of from 5 to 300.degree. C.

Abstract: The invention relates to processes for preparing 3-aminomethyl-3,5,5-trimethylcyclo-hexylamine (isophoronediamine, IPDA) having a high cis/trans isomer ratio. IPDA having a cis/trans isomer ratio in the range from 63/37 to 66/34 can be obtained in any desired cis/trans isomer ratio, irrespective of temperature, by reacting IPDA with H2 and NH3 in the presence of a hydrogenation catalyst. IPDA having a cis/trans isomer ratio of at least 73/27 which is an important starting material for the synthesis of polyurethanes and polyamides can be obtained by combining this isomerization process with distillative processes.