Using Hexamethyldisilazane for Dehumidification?

What are you trying to dehumidify? A closed volume can be easily dehumdified by dry nitrogen or argon purge . . . or rinse with alcohol and heat . . .

If you have any heat exchanger whose surface temperature is less then the dew point temperature of the entering air which is to be dehumidified then you can use it in the system. Otherwise you can use desiccants for dehumidification. I assume that it is a process industry.

"Otherwise you can use desiccants for dehumidification. I assume that it is a process industry."

I am leaning towards desiccant dehumidifier, but I am challenged by time. I want to do this inline bringing from high RH down to ~30%. Any suggestion how to this?

P2O5 will do - powder or tablets to be converted to phosphoric acid by adding water, but less dangerous than H2SO4.

Calcium-chloride and magnesium-chloride will do similar - also very dangerous if used as dry powder or tablets.

Not so dangerous: silica-gel (sometimes named blue.gel if colored with humidity indicating cobalt-chloride, blue if dry, rose if humid.)

Also not dangerous: the various types of zeolites - careful choice is necessary and the oldest but still super-useful activated charcoal.

The upper ones do not need regeneration but will need waste disposal. The lower ones will need regeneration by periodic heating.

And there is the possibility of cryo- or expansion drying.

How much stuff of which composition to dry?

RHABE

<...bringing from high RH down to ~30%. Any suggestion how to this...>

Warm it up.

Hi,

HMDS will do this, you should also consider TEOS.

Usually this is done in vacuum, so the degassed water vapor is replaced by some Si-O-H? molecules.

Did you have a look into the handbooks (existing in many old and newer editions) on Thin Film Technology,

one is (was originally) by Vossen and Kern,

the other one: Maissel and Glang

RHABE

Concentrated sulfuric acid can be used in a drying column if you're talking about inline chemical processing.

Thanks to all for your brilliant contributions. I will investigate further for the least risky and costly methods.