The invention provides a process for hydroformylation of diisobutene and a C4 to C7 olefin in a common reaction zone. The hydroformylation is carried out with synthesis gas in the presence of a homogeneous catalyst system that comprises at least Co or Rh and optionally a phosphorus-containing ligand.

The invention relates to processes for preparing aldehydes by hydroformylation of alkenes, in which an alkene-containing feed mixture is subjected to a primary hydroformylation with synthesis gas in the presence of a homogeneous catalyst system, the primary hydroformylation being effected in a primary reaction zone from which a cycle gas containing at least some of the products and unconverted reactants of the primary hydroformylation are drawn off continuously and partly condensed, with recycling of uncondensed components of the cycle gas into the primary reaction zone, and with distillative separation of condensed components of the cycle gas in an aldehyde removal stage to give an aldehyde-rich mixture and a low-aldehyde mixture. The problem that it addresses is that of developing the process such that it achieves high conversions and affords aldehyde in good product quality even in the case of a deteriorating raw material position. More particularly, a solution is to be found for making legacy oxo process plants capable of utilizing lower-value raw material sources. This problem is solved by separating the low-aldehyde mixture into a retentate and a permeate by means of a membrane separation unit in such a way that alkenes present in the low-aldehyde mixture become enriched in the permeate, while alkanes present in the low-aldehyde mixture become enriched in the retentate. The alkene-rich permeate is then transferred into a secondary reaction zone and subjected to a secondary hydroformylation therein with synthesis gas in the presence of an SILP catalyst system. The reaction product obtained from the secondary hydroformylation is recycled into the aldehyde removal stage.

The invention relates to processes for preparing aldehydes by hydroformylation of alkenes, in which an alkene-containing feed mixture is subjected to a primary hydroformylation with synthesis gas in the presence of a homogeneous catalyst system, the primary hydroformylation being effected in a primary reaction zone from which a cycle gas containing at least some of the products and unconverted reactants of the primary hydroformylation are drawn off continuously and partly condensed, with recycling of uncondensed components of the cycle gas into the primary reaction zone, and with distillative separation of condensed components of the cycle gas in an aldehyde removal stage to give an aldehyde-rich mixture and a low-aldehyde mixture. The problem that it addresses is that of developing the process such that it achieves high conversions and affords aldehyde in good product quality even in the case of a deteriorating raw material position. More particularly, a solution is to be found for making legacy oxo process plants capable of utilizing lower-value raw material sources. This problem is solved by separating the low-aldehyde mixture into a retentate and a permeate by means of a membrane separation unit in such a way that alkenes present in the low-aldehyde mixture become enriched in the permeate, while alkanes present in the low-aldehyde mixture become enriched in the retentate. The alkene-rich permeate is then transferred into a secondary reaction zone and subjected to a secondary hydroformylation therein with synthesis gas in the presence of an SILP catalyst system. The reaction product obtained from the secondary hydroformylation is recycled into the aldehyde removal stage.

The present invention concerns regulating the water content in a process for production of methacrolein. Methacrolein is used in chemical synthesis particularly as an intermediate for production of methacrylic acid, methyl methacrylate or else of active, aroma or flavor chemicals. The present invention is particularly concerned with regulating the water content in a process for production of methacrolein from formaldehyde and propionaldehyde via a Mannich condensation.

The present invention concerns regulating the water content in a process for production of methacrolein. Methacrolein is used in chemical synthesis particularly as an intermediate for production of methacrylic acid, methyl methacrylate or else of active, aroma or flavor chemicals. The present invention is particularly concerned with regulating the water content in a process for production of methacrolein from formaldehyde and propionaldehyde via a Mannich condensation.

The process disclosure relates to processes for recovering rhodium from a hydroformylation process. In one aspect, a tails stream from a product-catalyst separation zone is provided to at least one organic solvent nanofiltration separation membrane, wherein a final permeate stream exits a final organic solvent nanofiltration separation membrane, wherein the rhodium concentration in the final permeate stream is lower than the rhodium concentration in the tails stream. The permeate stream is incinerated on-site to create a rhodium-containing ash.

The invention relates to a method for obtaining acetoin from a medium containing same, the method comprising a step of dehydration by pervaporation using a hydrophilic membrane. With this method, the acetoin can be satisfactorily isolated and purified, both in terms of quality and yield. Furthermore, with the method of the invention it is possible to dispense with the use of solvents and prevent impurities from being generated.

The invention relates to a method for obtaining acetoin from a medium containing same, the method comprising a step of dehydration by pervaporation using a hydrophilic membrane. With this method, the acetoin can be satisfactorily isolated and purified, both in terms of quality and yield. Furthermore, with the method of the invention it is possible to dispense with the use of solvents and prevent impurities from being generated.

The present invention relates to a method for thermolytic fragmentation of a sugar into C1-C3 oxygenates, comprising cooling the fragmentation product downstream of the reactor to a cooling temperature of from 230 C. to 390 C. and then separating solids from the fragmentation product cooled to the cooling temperature. The present invention also relates to a system for performing the thermolytic fragmentation of a sugar into C1-C3 oxygenates. The method and the system are suitable for industrial scale production.