Production of large volumes of duterated hydrocarbons?

[Hologram0110]

Hi everyone,

I'm a nuclear engineering student so my chemistry knowledge is limited to a couple of courses in first year so please be patient with me.

I was wondering how difficult or expensive would it be to produce hydrocarbons with deuterium instead of hydrogen on a large scale? (say 100 tonnes with 95% or better Deuterium?) What about something like Monsanto OS-84 which is a mixture of partially hydrogenated terphenyls? (This has been used in the past as a coolant for nuclear reactors)

I ask because organic coolant for nuclear reactors offers some potential safety improvements but the hydrogen can absorb a significant number of neutrons compared to deuterium. I was wondering if the cost of producing duterated hydrocarbons would be more or less than the cost of the deterium to begin with.

All of the googling I've done went way over my head. I also think it was for laboratory scale production.

 

[chemisttree]

Hi everyone,

I'm a nuclear engineering student so my chemistry knowledge is limited to a couple of courses in first year so please be patient with me.

I was wondering how difficult or expensive would it be to produce hydrocarbons with deuterium instead of hydrogen on a large scale? (say 100 tonnes with 95% or better Deuterium?) What about something like Monsanto OS-84 which is a mixture of partially hydrogenated terphenyls? (This has been used in the past as a coolant for nuclear reactors)

I ask because organic coolant for nuclear reactors offers some potential safety improvements but the hydrogen can absorb a significant number of neutrons compared to deuterium. I was wondering if the cost of producing duterated hydrocarbons would be more or less than the cost of the deterium to begin with.

All of the googling I've done went way over my head. I also think it was for laboratory scale production.

It would be more since you start with deuterium (D2) when you make deutero-substituted organics.

 

[SteamKing]

1 kg of D2O from United Nuclear retails for US $695.00, so the cost of deuterated HCs is quite a bit more expensive.

 

[Hologram0110]

The cost of deuterium is a major part of the capital cost of some nuclear plants (research reactors, CANDU's, plutonium breeders).

Say you have deuterium in the for of D2O. How hard is it to make hydrocarbons without mixing deterium with hydrogen (which would down blend your D2O supply).

Could you start a process where you take nearly pure D2O add some carbon in some chemical form (with very little H) under the right temperature, pressure and catalyst to efficiently turn the D2O into deterocarbons? Can you eventually convert them to more complex longer/chain molecules (terphenyls, benzene)

My recollection from my high school organic chemistry class is yes, but all the reagents already had hydrogen in them. How would you go about it if you wanted to not introduce hydrogen to the mix? Is there a process that is conceivable at larger scales?

 

[Mike H]

As chemistree noted, synthesis of deuterated compounds typically involves D₂(g). I know there's quite a bit of older literature on the use of transition metals, deuterium oxide, and DCl to produce deuterated compounds, but my (vague) recollection is that certain compounds and/or functional groups are more likely to end up deuterated than others.

A general concern is that if you need to use deuterium oxide for this scheme of yours, you will have trouble getting some reactions to work as they'd prefer a different type of solvent. Not everything wants to behave well in aqueous solvent, especially in organic chemistry.

 

[DrDu]

You could make methane from Al2C3 and D2O.
Ethin from CaC2 and D2O. Formic acid from CO and D2O.
I suppose many other hydrocarbons can then be obtained from these compounds e.g. electrochemically.