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Author Topic: Selective Photo-oxidatiative dehydrogenation of Cyclohexane to Benzene  (Read 67 times)

DaMoose

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Selective Photo-oxidatiative dehydrogenation of Cyclohexane to Benzene
« on: September 06, 2009, 11:43:35 PM »
Proposed
 Photo oxidative Dehydrogenation of Cyclohexane to Benzene, using a
'TiO2 Catalys coated - Fluid Bed Reactor ' .

For which moose has found cheap OTC source for: likely to be usable, as is,
to construct the bed reactor.


These first two papers found claim low yields, reaching 33%.
However, with Sulfate doping, very high selectivity can be achieved: tunable by varying the catalyse type and reaction temperatures.

If you have ever shot propylhexedrine, then you know why this sounds interesting.
This bee would be happy to try a product of 30 some percent conversion, without any post reaction isolation & purification.

Now all that needs is to work out UV wavelength's in nanometers and find a variable intensity source:  LED's perhaps.

So what were dreaming of is 33% conversion of propylhexedrine to it's corresponding benzene with a GhettoMade  'TiO2-Catalytic Fluid Bed Reactor'.

This table is from one of the attached PDF's below..


Moose
« Last Edit: September 07, 2009, 03:24:17 AM by DaMoose »

Sedit

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Re: Selective Photo-oxidatiative dehydrogenation of Cyclohexane to Benzene
« Reply #1 on: September 06, 2009, 11:55:12 PM »
The selectivity may be high but the conversion itself if pretty low. Still non the lest reusing the unreacted product due to its selectivity looks a bit appealing. I also have concerns on how one could seperate unreacted product as there really is not much difference one could use to effect seperation.

Using the TiO2 particals there are also ways to convert Toluene to Benzaldahyde in good yeilds and I requested the paper some time back at Science
madness which I will look for.


Moved to Other Chemistry due to the varying uses for TiO2 bed reactors
There once were some bees and you took all there stuff!
You pissed off the wasp now enough is enough!!!

DaMoose

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Re: Selective Photo-oxidatiative dehydrogenation of Cyclohexane to Benzene
« Reply #2 on: September 07, 2009, 01:08:29 AM »
Assuming  selectivity is optimised,
what happens to the the formed benzene if subjected to forther irradiation's without removing it from the unconverted ?

Sedit

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Re: Selective Photo-oxidatiative dehydrogenation of Cyclohexane to Benzene
« Reply #3 on: September 07, 2009, 02:01:24 AM »
Given that its 99% selective now and conversion was on the order of 33% I would have to say nothing or else side reaction with the formed benzene would lower selectivity levels. In order to convert Benzene to CO2 they used a different Vandium pentoxide catalyst.

This is all assuming that Propylhexadrine will not react differently then the alkanes they are working with which I feel it just might. Still the links you provided are both broken and I can't seem to retrive them so could you possibly Download the PDFs and attach them as a file. This will also aid in them not being lost in the future and not having to link here to off site areas.
There once were some bees and you took all there stuff!
You pissed off the wasp now enough is enough!!!

DaMoose

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Re: Selective Photo-oxidatiative dehydrogenation of Cyclohexane to Benzene
« Reply #4 on: September 07, 2009, 04:12:03 AM »
Links removed and the PDF's attached

2bfrank

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Re: Selective Photo-oxidatiative dehydrogenation of Cyclohexane to Benzene
« Reply #5 on: September 07, 2009, 05:01:42 AM »
The light intensity was regulated at 100 mW/cm2. Each UVLED
module consists of up to 20 pieces of UV-LEDs (Nichia Corporation) emitting at 365 nm.

Thats from the patent, I saw the question, etc.
« Last Edit: September 07, 2009, 05:07:31 AM by 2bfrank »

DaMoose

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Re: Selective Photo-oxidatiative dehydrogenation of Cyclohexane to Benzene
« Reply #6 on: September 09, 2009, 09:52:19 PM »
Led intensity can be accomplished either 2 ways: linear or PWM.
the simplest of course is to use an individual current limiting resistor for each LED and power them with a variable power supply: the resistance values calculated for 'that powers supplies' max voltage.


365 Nanometers is pretty short wave for the world LED's ! Leading Edge Stuff !

There are allot of UV LED's that can be had from on line electronics suppliers I.E.
 Digikey or Mouser

here's a 385 nm at less than 1$ a piece  in single qty
Mouser Part #:  593-VAOL5GUV8T4  
Manufacturer Part #:  VAOL-5GUV8T4  
Manufacturer:  VCC  
Description:  LEDs Standard Ultraviolet (UV) 385nm 80mcd 30deg
 mcd millicandelas  ( an brightness intensity rating )      


http://www.s-et.com/index.html
UVTOP Series  240-400 nm available



I'll keep looking
« Last Edit: September 10, 2009, 12:47:50 AM by DaMoose »

DaMoose

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Re: Selective Photo-oxidatiative dehydrogenation of Cyclohexane to Benzene
« Reply #7 on: September 10, 2009, 01:03:40 AM »
Just a correction to the Heading post:

The tuning PDF is
Title: Photocatalysed selective oxidation of cyclohexane to benzene on MoOx/TiO2
Authors:  P. Ciambelli, , D. Sannino, V. Palma and V. Vaiano


and

The Sulphate doping increases the overall UV absorption: I believe I claimed that it mediated the selectivity.

It's the Polymolybdate species that's responsible for changing the selectivity of Titania.
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