concentration of liquid?

[tamis]

I have two alcohols that have varying degress of volatility, I assume. I am using them as inhibitors of bacterial growth and in order to do a complete comparison, I need to determine what their actual concentrations are, i.e., what percent stays in solution and which is in gas phase. There are no published Henry's Law constants, thus I was hoping to determine this using only the boiling points. Any suggestions?

[DrDNA]

??

Are you going to use them in a closed or an open system?

Are you mixing them with water? Do they azeotroph with water?

[tamis]

Thanks for your questions.

The systems are open--either as agar plates or liquid cultures. The alcohols are being added to aqueous solutions. There is no information as to whether as to whether they form azeotropic solutions. I would assume so, but wonder whether this would affect calculations much? They have reasonably high boiling points on their own (98, 130, 140 C) but are so stinky they must be volatilizing easily. The issue is that I want to compare the one with the lower boiling point with the two with higher bp.

[YT2095]

can you distill them over with some simple quickfit apparatus and a thermometer and not the temp jumps as each comes over in turn?

 

you will get temp leaps and then all you have to do at each spike is measure the amount that came over before the spike.

 

those temp jumps will also help to indicate what alcohol it is reasonably accurately

[DrDNA]

Thanks for your questions.

The systems are open--either as agar plates or liquid cultures.

I'm assuming then that they will have lids on them but not sealed?

 

 

They have reasonably high boiling points on their own (98, 130, 140 C) but are so stinky they must be volatilizing easily.

The issue is that I want to compare the one with the lower boiling point with the two with higher bp.

 

I thought you said that there were 2 alcohols.

 

Wait a minute. You said there are no published Henry's law info....and you have bps......you probably know their names, but you haven't said what they are? What are they?

[tamis]

Sorry if I am making this confusing! I'll try to clarify exactly what I'm looking for.

I do know what they are. They are 3-methyl-2-buten-1-ol (bp 143 C), 3-methyl-3-butenol-1-ol (bp 130 C) and 2-methyl-3-buten-2-ol (bp 99 C). The only published Henry's law constant is for 232 (65 atm-1). I may have said only 2 as 331 and 321 behave the same in my assays.

The growth containers do have lids, but are not air-tight.

I am asking the question because I am concerned that I cannot compare the 2 primary alcohols with the secondary alcohol with regards to their affect on cell growth at a particular concentration. They are all known volatiles emitted by various organisms. I guess a simpler question: how can I figure out their solubility?