1. A process for the production of a catalyst for the dehydrogenation of methylpiperidine to methylpyridine comprising in the order (a) to (d) the steps of
(a) providing a carrier comprising 65-100 weight % silicon oxide and 0-35 weight % aluminium oxide,
(b) impregnating the carrier with palladium, whereby the carrier is brought into contact with an aqueous solution of a palladium-ammonia-complex to obtain a catalyst,
(c) drying the catalyst with air at a temperature below 80\xb0 C. and
(d) calcinating the catalyst at a temperature below 200\xb0 C.
2. The process of claim 1, further comprising after step (d)
(e) activating the catalyst with hydrogen.
3. The process of claim 1, wherein the drying step (c) is carried out at a temperature between 20\xb0 C. and 60\xb0 C.
4. The process of claim 1, wherein the calcinating step (d) is carried out with air andor at a temperature between 80\xb0 C. and 200\xb0 C.
5. The process of claim 1, wherein the activating step (e) is carried out under active depletion of oxygen.
6. The process of claim 1, wherein the catalyst comprises 0.5 to 8 weight % palladium.
7. A dehydrogenation catalyst for the conversion of methylpiperidine to methylpyridine, obtainable by a process of claim 1.
8. A process for the production of methylpyridine from methylpiperidine, wherein methylpiperidine is contacted with a dehydrogenation catalyst according to claim 7.
9. The process of claim 8, wherein the methylpiperidine is 3-methylpiperidine.
10. The process of claim 8, wherein the reaction is carried out under a hydrogen andor nitrogen atmosphere.
11. The process of claim 8, wherein the reaction is carried out in the gaseous phase at a temperature between 180\xb0 C. and 400\xb0 C.
12. The process of claim 8, wherein the catalyst is mixed with aluminium.
13. The process of claim 12, wherein the methylpiperidine is initially contacted with a first catalystaluminium mixture, and subsequently contacted with a second catalystaluminium mixture, wherein the ration catalystaluminium in the first mixture is lower than in the second mixture.
14. The process of claim 8, wherein before the dehydrogenation reaction the methylpiperidine is produced in a cyclization reaction from methyl-1,5-diaminopentane, wherein the cyclization reaction is carried out in a first reactor and the dehydrogenation reaction is carried out in a second reactor, both reactors are interconnected and both reactions are carried out in a continuous process.
15. The process of claim 8, wherein the methylpiperidine produced in the cyclization reaction is obtained in a mixture with ammonia, and the mixture is fed into the second reactor without prior separation of the ammonia.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A transmission measuring system comprising:
(a) a pair of ultrasonic transducers, respectively mounted on upstream and downstream regions of a flow tube,
a switching device for switching an operational mode of each of the transducers alternatively to a transmitting and a receiving mode thereof such that a first one of the pair of transducers is first set in the transmitting mode then in the receiving mode and a second one of the pair of transducers is first set in the in the receiving mode and then set in the transmitting mode,
a driving power source for driving the ultrasonic transducers such that a signal is propagated through fluid in the flow tube from the first ultrasonic transducer to the second ultrasonic transducer and such that a signal is propagated through the fluid in the flow tube from the second ultrasonic transducer to the first ultrasonic transducer, whereby a signal is propagated between the ultrasonic transducers in each of an upstream-ward direction and a downstream-ward direction in the flow tube, and
an amplifier which, for each said signal propagated through the fluid and received by one of the ultrasonic transducers in the receiving mode, amplifies the signal propagated through fluid in the flow tube and received by the ultrasonic transducer in the receiving mode;
(b) an analog-digital converter which, for each of the signals output from the amplifier, converts the amplified signal into digital data;
(c) a programmable logic device for receiving the digital data for each of the amplified signals and storing the received digital data in a memory;
(d) a clock source for providing a clock signal to the programmable logic device; and
(e) a central processing unit for reading out the digital data stored in the memory and processing the read out digital data to obtain a propagation time of the signal propagated in the upstream-ward direction of the flow tube and a propagation time of the signal propagated in the downstream-ward direction of the flow tube and to compute a flow rate of the fluid flowing through the flow tube based on a difference between the propagation times,
wherein the programmable logic device delivers a start signal for measurements to the driving power source based on the clock signal from the clock signal source, generates a plurality of delayed clock signals through an internal element thereof, delivers one of the delayed clock signals to the analog-digital converter, and changes a delay time of the clock signal to be delivered to the analog-digital converter with time with respect to the start signal for measurements.
2. A transmission measuring system comprising:
(a) a pair of ultrasonic transducers, respectively mounted on upstream and downstream regions of a flow tube,
a switching device for switching an operational mode of each of the transducers alternatively to a transmitting and a receiving mode thereof such that a first one of the pair of transducers is first set in the transmitting mode then in the receiving mode and a second one of the pair of transducers is first set in the in the receiving mode and then set in the transmitting mode,
a driving power source for driving the ultrasonic transducers such that a signal is propagated through fluid in the flow tube from the first ultrasonic transducer to the second ultrasonic transducer and such that a signal is propagated through the fluid in the flow tube from the second ultrasonic transducer to the first ultrasonic transducer, whereby a signal is propagated between the ultrasonic transducers in each of an upstream-ward direction and a downstream-ward direction in the flow tube, and
an amplifier which, for each said signal propagated through the fluid and received by one of the ultrasonic transducers in the receiving mode, amplifies the signal propagated through fluid in the flow tube and received by the ultrasonic transducer in the receiving mode;
(b) an analog-digital converter which, for each of the signals output from the amplifier, converts the amplified signal into digital data;
(c) a programmable logic device for receiving the digital data for each of the amplified signals and storing the received digital data in a memory;
(d) a clock source for providing a clock signal to the programmable logic device; and
(e) a central processing unit for reading out the digital data stored in the memory and processing the read out digital data to obtain a propagation time of the signal propagated in the upstream-ward direction of the flow tube and a propagation time of the signal propagated in the downstream-ward direction of the flow tube and to compute a flow rate of the fluid flowing through the flow tube based on a difference between the propagation times,
wherein the programmable logic device delivers a clock signal to the analog-digital converter based on the clock signal from the clock signal source, generates a plurality of delayed clock signals through an internal element thereof, delivers one of the delayed clock signals to the driving power source as a start signal for measurements, and changes the clock signal to be delivered to the analog-digital converter with time with respect to the start signal for measurements.
3. A transmission measuring system comprising:
(a) a pair of ultrasonic transducers, respectively mounted on upstream and downstream regions of a flow tube,
a switching device for switching an operational mode of each of the transducers alternatively to a transmitting and a receiving mode thereof such that a first one of the pair of transducers is first set in the transmitting mode then in the receiving mode and a second one of the pair of transducers is first set in the in the receiving mode and then set in the transmitting mode,
a driving power source for driving the ultrasonic transducers such that a signal is propagated through fluid in the flow tube from the first ultrasonic transducer to the second ultrasonic transducer and such that a signal is propagated through the fluid in the flow tube from the second ultrasonic transducer to the first ultrasonic transducer, whereby a signal is propagated between the ultrasonic transducers in each of an upstream-ward direction and a downstream-ward direction in the flow tube, and
an amplifier which, for each said signal propagated through the fluid and received by one of the ultrasonic transducers in the receiving mode, amplifies the signal propagated through fluid in the flow tube and received by the ultrasonic transducer in the receiving mode;
(b) an analog-digital converter which, for each of the signals output from the amplifier, converts the amplified signal into digital data;
(c) a programmable logic device for receiving the digital data for each of the amplified signals and storing the received digital data in a memory;
(d) a clock source for providing a clock signal to the programmable logic device; and
(e) a central processing unit for reading out the digital data stored in the memory and processing the read out digital data to obtain a propagation time of the signal propagated in the upstream-ward direction of the flow tube and a propagation time of the signal propagated in the downstream-ward direction of the flow tube and to compute a flow rate of the fluid flowing through the flow tube based on a difference between the propagation times,
wherein the programmable logic device receives the clock signal from the clock signal source, generates a plurality of delayed clock signals through an internal element thereof, delivers one of the delayed clock signals to the driving power source as a start signal for measurements, delivers one of an identical delayed clock signal and a different delayed clock signal to the analog-digital converter as a clock signal based on which the analog-digital converter is to be operated, and changes the clock signal to be delivered to the analog-digital converter with time with respect to the start signal for measurements.