While expensive compared to traditional commodity solvents, “Trans” (the 25-50% solvent in your mixture) is slowly replacing DCM, nPB, and other hit-list solvents in industry.  It’s a good cleaner, has a very fast evaporation rate, and exhibits a more favorable tox profile than may traditional solvents.  Only problem is it’s flammable.  However, its ability to project a flame in aerosol applications (the arena I personally work in) is easily suppressed with just 5-15% of a nonflammable fluorocarbon—often trans-1-chloro-3,3,3-trifluoropropene and/or one of the decafluoropentanes—although the mixture may still flash in closed-cup tests.

 

The data you’re supplying below doesn’t necessarily sound wrong, though the third component has the lowest vapor pressure of the trio, which is a little curious..  Is this billed as an azeotrope?  Either way, if your customer is currently using neat nPB, then there should be already flash point/flammability concerns in play.  If that is in fact the case, they may well be able to use this mixture in drop-in fashion, depending on the safety measures currently employed.  Correction—your customer may be able to get away with using less PPE (but probably not less ventilation) since “Trans” and particularly the fluorinated components don’t seem to have the same degree of health hazards that have recently been coming to light with nPB.

 

 

Hi, everyone,

 

I received an SDS and label today for a new mixture for chemicals that I don’t have experience with, and I am questioning the SDS information. Here are the components:

1,1,1,3,3-pentafluorobutane- 50-70%

1,2-trans-dichloroethylene- 25-50%

1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether- 1-8%.

 

According to the SDS, the manufacturer has tested this mixture according to ASTM D56 and found that it does not flash, but the two main components are flammable (PGII) (and the third may be as well). There is also a statement on the SDS that the mixture “may flash if there is a vapor to air concentration in the range of 5.4% to 9.4% exposed to a high energy ignition source, such as a welding torch.” Normally I would suspect that a mixture of 92% flammable components would also be flammable, but I don’t have experience with these kind of solvents. I don’t have a sample of this material to test it myself either.

 

Does anyone have experience with these sorts of solvent mixtures that could provide some insight as to why or why not this mixture might be flammable? My customer really wants to switch to this material, since it is billed as safer than the n-propyl bromide he is currently using. I’d like to be able to give him accurate information before he switches his SOP. So any help would be appreciated.

 

Thanks,

Janice

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