摘要:
Processes for making trioxane, polyoxymethylene and polyoxymethylene copolymers from formaldehyde, made by the dehydrogenation of methanol in the presence of a catalytic active species set free from a sodium compound, at a temperature in the range of 300° C. to 1000° C., wherein a carrier gas stream which has a temperature above the dehydrogenation temperature is fed to the reactor.
摘要:
In a process for preparing formaldehyde from methanol by dehydrogenation in a reactor in the presence of a catalyst at a temperature in the range from 300 to 1000° C., a circulating gas stream comprising by-products of the dehydrogenation is passed through the reactor.
摘要:
In a process for separating liquid mixtures comprising formaldehyde, trioxane, alcohol, hemiformal formed from the formaldehyde and the alcohol, usual minor components and up to 5% by weight of water, the liquid mixture is distilled batchwise or continuously at reduced pressure, atmospheric pressure or superatmospheric pressure in suitable apparatuses which are to be connected to one another in an appropriate manner, and the trioxane is produced in very high purity. The other materials of value, formaldehyde and alcohol, present in the mixture can likewise optionally be separated off and recycled or used otherwise, while the minor components are ejected.
摘要:
The instant invention is a paging device which couples to a cellular telephone allowing independent use of the cellular telephone and the paging unit. The paging unit includes a speaker for converting received signals into a dial tone for placement against either a conventional land based telephone or a cellular telephone for automatically redialing of numbers received by the paging unit. The paging unit can be coupled to a compatible cellular telephone wherein the pager and telephone can be carried as a single unit allowing screening of incoming calls and an automatic callback of received paged calls.