Is Bromothane™ an Azeotrope?
What Is an Azeotrope?
Why Is That Important?

Most of the Bromothane™ blends are azeotropes, and that's important because it lowers your costs, boosts cleaning effectiveness and enhances worker safety. In the chemical world, these are all considered really good things to do.

So the next question you're going to ask is, how does an azeotrope do that? Good question. For the answer, we have to go back to Chemistry 101.

First, an azeotrope is best described as a constant boiling blend. To be an azeotrope, the material has to be a mixture or a blend of at least two different elements or compounds. For example, "neat" nPB is not an azeotrope because there's nothing else in it but molecules of nPB. Bromothane™ R is a mixture of nPB and isopropyl alcohol. So Bromothane™ R could be an azeotrope (and is, as we will explain in a minute).

Now let's consider the boiling point of these materials.

The boiling point of nPB is about 70° C/170° F. But mix nPB with a small but precise amount of alcohol and the boiling temperature suddenly drops. This is very odd and unexpected. The two chemicals are still separate and distinct in the mixture; there has been no chemical reaction in which they actually change their chemical state. But somehow the two chemicals are working together to lower their combined boiling point. And, most importantly, when we boil some of this mixture in a beaker the two constituents will boil off at the same rate.

Let's suppose the mixture we are testing is 97% nPB and 3% alcohol. If we measure the vapors coming off the boiling liquid, we would be pleased to notice that the mixture of vapors also was at the same 97:3 mixture. When we chill those vapors and distill the material, it again will have the same 97:3 mixture. In fact, no matter what we do the mixture it always stays at the 97:3 proportions. This means we have created an azeotrope.

There is a bit of magic to making azeotropes. Not all liquids form azeotropes because the density, boiling point and surface tension all has to be exactly right.

Because azeotropes are way cool. Azeotropic behavior allows clever engineers to deliver the benefits of a mixture with the convenient handling and storage of a single compound. Perhaps one chemical is nonflammable but not a great cleaner. But mix it with a super cleaner that happens to be flammable and what happens? You get a great nonflammable cleaner. It's like getting two different solvents out of one drum.

For example, azeotropes are very easy to distill and recover. If the solvent in a vapor degreaser acts as an azeotrope then the solvent can be boiled away and distilled while the contamination -- fluxes, oils, water, belly-button lint and such -- stay "trapped" in the liquid at the bottom of the machine. In effect, using azeotropic solvents allows us to trap and concentrate the contamination by distillation instead of using filters and membranes and such.

Another important benefit of an azeotrope is the unexpected ability to mix flammable and nonflammable ingredients to produce a stable nonflammable mixture. This is an amazing chemical phenomenon. Imagine mixing flammable ingredients -- like alcohol -- into Bromothane™ R and yet still be retain the convenient and safe handling characteristics of a nonflammable chemical. This is a big boost for safety!

Lastly, azeotropes permit the "tweaking" of a blend to obtain unique physical properties which makes the blends useful across a broad range of applications. For example, nPB is a very aggressive cleaner. But add some other ingredients in azeotropic proportions, and MicroCare and Great Lakes can make Bromothane™ into a blend that is milder and easier to handle. The possibilities are almost limitless.

Here's a quick summary of the benefits of an azeotropic solvent:

• Safety: First and foremost, all of the Bromothane™ solvents are nonflammable. This makes cleaning processes simpler, safer and more reliable by an order of magnitude.

• Easy Operation: Manufacturing personnel deal with one solvent instead of a solvating agent and rinse agent. A single azeotropic solvent eliminates the need to monitor the ratio of solvating agent and rinse agent.

• Easy Monitoring: Monitoring the contamination level in Bromothane™ azeotropic solvents is much easier than determining the soil level in a solvating agent. Most manufacturing companies do not have the laboratory capability to determine the soil level in the solvating agent so they prematurely discard the solvating agent, to preserve quality production. This discarding of the solvating agent results in greater solvent consumption.

• Higher Soil-Loading Capability: Azeotropic solvents have higher soil-loading capability, which allows the solvent to be used longer and thus reduces solvent purchases.

• Faster Cleaning: Azeotropic solvents clean much faster. This can reduce the cleaning cycle time by as much as 75%, increase productivity, and eliminate production bottlenecks involving the cleaning operation.

• Minimal Odor: Bromothane™ azeotropic solvents have minimal odor (depending upon the base material) which can help minimize workplace aromas, employee complaints, and residual odor left behind on the cleaned parts. However, in the case of Bromothane™ this is a minor point because ALL nPB products have a pronounced aroma, no matter how hard we try to mask it with additives.

• Lower Constant Temperatures: Bromothane™ azeotropic solvent cleaning systems operate at lower constant temperatures, which provides greater compatibility and reduces energy costs. In co-solvent systems, the operating temperature can fluctuate dramatically as the ratio between the solvating agent and rinse agent changes.

• Less Expensive: Both solvent and energy costs are lower with Bromothane™ azeotropic solvent systems. Azeotropic solvents are normally less expensive than the combined costs of two sol-vents used in a co-solvent process. Less azeotropic solvent is consumed because it has higher soil loading capability and is reclaimable by distillation. Significant solvent loss occurs in a co-solvent process when the agent is added to an operating system because of the two vastly different boiling points.

• Versatile Equipment Use: Single-sump vapor degreasers can be used with Bromothane™ azeotropic solvents; boil-sump immersion is optional.

• One Supplier: Bromothane™ azeotropic solvents are available in Canada, the U.S. and Mexico from one supplier: MicroCare Marketing Services.

One special note: The BromoBooster ™ concentrate is a simple blend and not an azeotrope nor even a near-azeotrope. This product has special handling requirements as listed on its product specification.  

Updated: Feb. 23, 2004
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