Should you Use a Woulff Bottle with your Rotary Evaporator?

The Woulff bottle, a seemingly simple piece of glassware, is a two-necked bottle (which also has a three-necked variant) first described by Peter Woulfe (1727-1803).  In this blog post, we’ll delve into the world of Woulff bottles, exploring their design, applications, as well as both the advantages and disadvantages of using them in your lab setup.

Designed for Functionality

Crafted from robust borosilicate glass, Woulff bottles come in various sizes, from small vials to larger containers. Their defining feature is the two or three necks, often with one of more of the necks boasting a long tubereaching the bottle’s bottom.

While all such bottles are deemed “Woulff Bottles”, Woulff bottles for rotary evaporation applications should have two necks and any tube entering the bottle from the inlet neck should be truncated, reaching no more than halfway down the bottle. Unlike in many other applications which use a Woulff bottle, users of rotary evaporators should not want the vapor stream to pass through any pooled liquid at the bottom of the vessel, as this could cause bubbling, splashing, and aerosolization of liquids; exactly what we seek to protect from by adding a Woulff bottle to our rotary evaporation process stream.


Woulff bottles and Rotary Evaporation

Woulff bottles play a protective role in the efficient recovery of solvents during rotary evaporation. Attached downstream of the rotary evaporator’s condenser, the Woulff bottle captures small condensate particles which may be sucked out of the condenser by the vacuum pump, thereby protecting the vacuum pump from flooding.

Vacuum Pump Explained [1]

Vacuum pumps used in rotary evaporation are most often diaphragm pumps. If vapors reach the diaphragm pump, they will condense inside the pump. Likewise, any small liquid droplet that reaches the pump may reside inside it and not immediately be discharged. This accumulation of fluid in the pump may cause flooding, which can cease its operation and may permanently damage the pump (although many times a vacuum pump can simply be “aired out” by running it without connecting it to anything).

Woulff bottles therefore can play an important role in protecting the diaphragm pump.


Limitations to Consider

While Woulff bottles are valuable tools, they are limited in their utility in a number of important ways:

  • Limited Capacity: Woulff bottles are generally relatively small and hold a modest amount of liquid. Keep an eye on it to ensure it doesn’t get too full, and empty after each use if there is a noticeable amount of liquid accumulation.
  • Fragility: Glass Woulff bottles, like any glassware, are susceptible to breakage, especially if not handled with care. This can be a safety hazard, particularly when dealing with hazardous liquids and vapors. A small Woulff bottle can be easily knocked over by accidental contact with it or any of the tubing it is attached to. To protect your Woulff bottle from being accidentally knocked over, ensure it is secured to a study object.
  • No ability to condense vapors: A Woulff bottle is not a cold trap! It does not provide any additional cooling and while it will trap most aerosolized liquids, it will be largely unable to trap any uncondensed vapor. If your setup is not fully condensing the vapors, a Woulff bottle will offer little protection.

A Woulff bottle is therefore largely unable to prevent one of the most common problems in rotary evaporation: incomplete condensation of the vapor. Incomplete condensation is caused by one of three factors:

  1. The coolant in the condenser is not cold enough.
  2. The cooling source (eg. the chiller or dry ice condenser) does not have enough cooling capacity. That is, heat is being added to the system by the rotary evaporator’s heating bath faster than the cooling source can remove it.
  3. The residence time of the vapor in the condenser is too low. Generally, this means your vacuum pump is too large / too fast, resulting in the vapor being pulled through the condenser faster without sufficient time to transfer enough of its heat to the condenser.

All three of these problems are mitigated by having a system with a high cooling capacity, very low temperatures, and high condenser surface area. Essentially, you want to maximize the heat transfer. By using one of our Rotary Evaporators, that is exactly what you are doing. Our systems reach an extremely cold temperature while maintaining a very high cooling capacity, and our tightly wrapped metal condenser coils increase both the surface area and heat conduction. The EcoChyll evaporators render Woulff bottles (and cold traps) unnecessary.



Diaphragm Pump Explained. (n.d.). SAVREE.


What are Azeotropes?

What are Azeotropes?

An azeotrope is a liquid mixture with a unique feature: its vapor phase possesses the same composition as the liquid phase at its boiling point. This means that boiling an azeotrope does not alter the relative concentrations of its components. Unlike typical mixtures where the more volatile component evaporates first, azeotropes boil as a single entity, maintaining their equilibrium. 


Types of Azeotropes 

Azeotropes can be classified by a variety of means:

Homogenous and Heterogenous Azeotropes:

  1. Homogeneous Azeotropes: These mixtures, like ethanol-water, are miscible and for a singly, uniform phase. 
  2. Heterogeneous Azeotropes: These mixtures, like oil-water, are immiscible and exist as distinct layers within the flask. 

Positive and Negative Azeotropes:

  1. Positive Azeotropes: Also known as “minimum-boiling” azeotropes. They have lower boiling points than their components.
  2. Negative Azeotropes: Also known as “maximum-boiling” azeotropes. They have higher boiling points than their components.

Temperature-Minimum and Pressure-Maximum Azeotrope Mixtures of Chloroform and Methanol[1]

Binary and Ternary Azeotropes:

As their names suggest, binary azeotropes are made up of two constituents, whereas ternary azeotropes are made up of three constituents. 


Significance in Rotary Evaporation

Azeotropes can both hinder and aid the separation process. On one hand, if your desired compound forms an azeotrope with your solvent, complete purification through simple evaporation becomes impossible. This presents a hurdle in isolation, requiring alternative techniques like extraction or azeotrope breaking with entrainer molecules. However, you can harness azeotropes to your advantage:  If there is a contaminant in your solvent, and this contaminant forms an azeotrope with the solvent at a lower boiling point than the desired product, you can exploit this property to selectively remove the contaminant. Here’s how it works:

  1. Identify the Azeotrope Formation: Determine if there is an azeotrope formation between the solvent and the contaminant.
  2. Boiling Point Selection: If the contaminant forms an azeotrope with the solvent at a lower boiling point, you can choose a specific temperature for evaporation.
  3. Selective Evaporation: By evaporating the mixture at this specific temperature, you will selectively remove the azeotrope-forming contaminant, leaving behind the remaining desired product.


Entrainer Molecules

Entrainer agents, also called azeotropic agents, are molecules that can be added to a liquid mixture to help in the separation of components using distillation, specifically when your mixture forms an azeotrope. In rotary evaporation, entrainer agents are used to break down azeotropes and assist in separating its components. Here’s how they work:

1) Breaking Azeotropes: Entraining agents work by disrupting the vapor-liquid equilibrium, efficiently altering the azeotropic behavior. By using an entrainer, the azeotropic composition is affected, leading to separation based on the altered boiling points.

2) Improved Separation Efficiency: Entrainers can upregulate the volatility of one component compared to the other, contributing to its preferential evaporation. This selective vaporization leads to an improved separation efficiency, specifically when working with components that have similar boiling points or form azeotropes.

3) Enhancing Distillation Performance: Azeotropic agents can also alter the relative volatility of components, decreasing the temperature needed for separation. This contributes to energy savings and enhanced efficiency in rotary evaporation.

Selecting Suitable Entrainers

Choosing an entrainer depends on the following factors: the type of components that need to be dissociated, their boiling points, solubility, and compatibility with the system. Examples of entrainer molecules include ethanol, benzene, toluene, and different chlorinated solvents, among others. You will need to look up what entrainers, if any, are available for your particular azeotrope, as there are no universal entrainers.


Azeotropes in Practical Applications 

Controlled Evaporation:

  • Paint thinners and degreasers: The acetone-chloroform azeotrope (68% acetone) exhibits a controlled evaporation rate crucial for these applications. The azeotrope ensures consistent cleaning performance without flash evaporation or rapid drying, making it ideal for precise removal of grease and paint residues.
  • Drying heat-sensitive materials: Certain azeotropes can be tailored to evaporate at lower temperatures, making them suitable for drying heat-sensitive materials.

Separation and Purification:

  • Recovery of high-purity ethanol: While the ethanol-water azeotrope limits ethanol concentration in homebrewing (specially with a recent rise in the use of rotary evaporators by professional mixologists in craft bars), techniques like azeotropic distillation using benzene can break the azeotrope and yield purer ethanol (around 99.5%). This process, though not recommended for home use due to safety concerns, demonstrates the potential of azeotropic distillation in achieving high purity. It is also necessary to mention that benzene cannot be used in any applications intended for personal consumption, as it is highly carcinogenic. 
  • Extraction of essential oils: Some essential oils form azeotropes with specific solvents, allowing for their selective extraction from plant materials. 



WilfriedC at English Wikipedia, CC BY-SA 3.0 <>, via Wikimedia Commons

Teledyne LABS is new distributor of Ecodyst rotary evaporation systems for the laboratory

Teledyne LABS is now a major distributor of Ecodyst evaporation systems used in laboratories worldwide.

Ecodyst uses proprietary technology for the efficient and gentle re​moval of solvent from samples in numerous advanced scientific processes. Principle users of Teledyne LABS chromatography instruments and Ecodyst benchtop rotary evaporator (rotavap) and large-scale evaporation systems include the pharmaceutical and agrichemical industries, contract laboratories, and academic and government research institutions.

“The Teledyne LABS/Ecodyst partnership is a natural extension of Teledyne LABS’ expertise in flash and preparative chromatography and Ecodyst’s ground-breaking developments in rotary evaporation design and operation,” said Joshua Lovell, Teledyne LABS’ Product Line Manager – Pharma R&D Product. “Evaporation follows chromatography in the purification process, and the Teledyne LABS and Ecodyst partnership is a natural progression of those close ties.”

Teledyne LABS and Ecodyst share a strong, global reputation in the marketplace for the utmost in quality, service and leadership, and an intimate understanding of the chemist’s needs in sample purification. “Visiting with our customers and understanding their workflow challenges, we realize Ecodyst offers a dramatic step forward in the function of evaporation technology, and we want to deliver that benefit to our customers,” Lovell said.

Using a proprietary self-cooling technology, Ecodyst has evolved the rotavap to be more efficient, to have expanded capacity, and to be less costly to operate than traditional methods. The Ecodyst difference offers significant advantages in time and materials savings compared to outdated evaporative technologies.

By eliminating the need for consumable coolants like antifreeze, dry ice and water, Ecodyst systems also promote Green Chemistry as a step in creating a sustainable future. Ecodyst systems include:

  • EcoChyll X1: Condenser with integrated chiller for add-on to any existing rotavap system.
  • Ecodyst Hydrogen Benchtop all-in one rotavap solutions with integrated chillers.  There are two different products offered in this category.
  • Ecodyst Large-Scale vertical evaporation options in a variety of sizes and capacities to meet needs from 12 L to 200 L.

Ecodyst’s patented self-cooling technology was devised and developed by Ecodyst CEO George Adjabang, a former medicinal chemist with over 15 years of experience in the laboratory. Adjabang grew frustrated with some of the challenges in relying on dry ice as a consumable to cool the rotavap in his labs and invented a solution that vastly improved rotary evaporation.

“We are excited to partner with Teledyne LABS, a customer-centered organization with many decades of experience providing purification solutions to scientists worldwide,” Adjabang said. “Ecodyst has emerged as an innovative leader and creator of modern evaporator technology, and we approach evaporation equipment innovation with a deep understanding of the needs and challenges facing scientists in chemistry labs and industries performing chemistry.”

Lovell said ISCO’s story begins with a singular visionary as well. “Both companies emphasize innovation to improve customer workflow, robust construction and ease of use, and have throughout their existence.”

The Ecodyst solution offers many benefits:

  • Increased chilling capacity.
    • Able to have controlled temperature set-points to balance chilling capacity with the evaporation need.
    • More efficient chilling process by using proprietary condenser material with significantly better heat transfer properties versus glass.
  • Environmentally friendly and sustainable
    • Eliminates the need for consumables like dry ice or water.
    • Increased efficiency through a single heat exchange cycle versus two heat exchange cycles required with a recirculating chiller.
  • Ready to go immediately.
    • No need to preplan around the next dry ice delivery.  Ready to go when you are.
    • Faster start-up times to get the rotavap to temperature significantly more quickly compared to recirculating chillers.
  • Maximizes bench space
    • No need to reserve valuable lab space for an external recirculating chiller.

Lovell said customers will be able to purchase Teledyne LABS and Ecodyst systems separately or in economical bundles that provide an ideal pairing of chromatography and rotavap technologies. “We look forward to a long-term partnership with Ecodyst as we join forces to present solutions to perfectly suit the wide-ranging needs of our shared customer base,” he said.

About Teledyne LABS

Teledyne LABS consolidates Teledyne CETAC, Hanson, ISCO chromatography and pumps, Leeman Labs and Tekmar for Chromatography, GC Sample Prep, Elemental Analysis, Automated Liquid Handling, Pumping and Dissolution, Diffusion, and Physical Tablet Testing. These complementary brands support our commitment to delivering innovative laboratory instruments that improve our environmental sustainability and quality of life.​

About Ec​odyst

Ecodyst is the innovative creator of the next generation of rotary evaporators. Our proprietary self-cooling technology has revolutionized the rotary evaporator to increase efficiency and output while reducing the operational costs, footprint, and labor requirements. This disruptive technology will ultimately set new standards worldwide for scientific instruments. Ecodyst’s product line has a wide range of models, including benchtop systems for discovery chemistry and industrial models for process chemistry and commercial applications.​​

Back to Basics: Rotary Evaporation vs. Classical Distillation

In today’s no-holds-barred blog post, we’ll be facing off rotary evaporation and classical distillation: the different advantages each one presents over the other, and the key differences in efficiency, the process itself, the equipment used, and applications.


Some of the advantages of using rotary evaporation

1-Faster Evaporation: One of the primary advantages is the significantly faster evaporation rate achieved with rotary evaporation. The rotating flask creates a thin film of the liquid, maximizing the surface area exposed to the vacuum and heat. This accelerates the evaporation process compared to classical distillation.

2-Efficient for Heat-Sensitive Compounds: Rotary evaporation is particularly beneficial when working with heat-sensitive compounds. The gentle rotation and reduced pressure in the system minimize the exposure of the sample to high temperatures, preserving the integrity of thermally sensitive substances (you can read about how to set the right temperature for your rotary evaporator here).

3-Enhanced Concentration Capability: The increased efficiency of evaporation allows for better concentration of the desired components in the sample. This is advantageous in applications where obtaining a more concentrated solution is essential, such as in the preparation of concentrated extracts or in the concentration of dilute solutions.

4-Reduced Degradation of Compounds: The lower risk of thermal degradation is an advantage, especially when dealing with compounds that may break down or undergo chemical changes at elevated temperatures. Rotary evaporation’s controlled and efficient process helps maintain the stability of delicate compounds.

5-Versatility in Sample Types: Rotary evaporation is versatile and suitable for a wide range of sample types, including those with complex compositions or containing volatile and temperature-sensitive components. This versatility makes it applicable in various fields, from chemistry and biology to the preparation of pharmaceuticals and natural product extractions.


Some of the advantages of using Classical distillation

1-Simplicity: Classical distillation is a simpler and more straightforward process compared to rotary evaporation. It involves heating a liquid mixture to create vapor, which is then condensed and collected. There are fewer components and moving parts involved, making it easier to set up and operate.

2-Scale: Classical distillation can be easily scaled up for large-scale industrial applications. It’s commonly used in industries such as petrochemicals, pharmaceuticals, and the production of alcoholic beverages, where large quantities of liquids need to be separated (however, our rotary evaporators allow for more scaling than any other rotary evaporator on the market, scaling up to 200L true capacity).



Classical Distillation:

Classical distillation is a well-established and straightforward method that is widely employed for various separation processes. Its simplicity makes it accessible for routine application in labs and industries. However, classical distillation may have limitations in terms of speed, especially when dealing with mixtures that require precise temperature control. Maintaining specific temperatures throughout the process can extend the overall duration of distillation. In terms of energy consumption, classical distillation does not offer any edge over rotary evaporation. 

Rotary Evaporation:

Rotary evaporation is recognized for its efficiency, particularly in scenarios where speed is essential. The unique design of rotary evaporators enhances the evaporation process, making it more efficient for certain applications. On top of this, our rotary evaporators at Ecodyst are far more energy efficient (they use over 50% less electricity) than classical rotary evaporators. 


The Process

Classical Distillation:

In classical Distillation, heat is applied to the entire liquid mixture in the flask. As the liquid reaches its boiling point, and vapor rises through the column, condensation occurs in the condenser leading to the collection of the liquid in a separate flask.

Rotary Evaporation:

The rotation of the flask serves a crucial role in the process: by increasing the liquid’s surface area, a thin film of the liquid is created on the inner surface of the flask, maximizing the exposure to vacuum, and promoting faster evaporation. Vapors are condensed in a separate condenser and collected in a receiving flask. 


Equipment Used

Classical Distillation:

  • Typically involves a round-bottom flask containing the liquid mixture
  • Vapors rise through a column and enter a condenser, where they are cooled and condensed
  • Recirculating chiller
  • The condensed liquid is collected in a separate flask

Rotary Evaporation:

  • Rotary evaporator, which includes a round-bottom flask attached to a rotating mechanism
  • A condenser is used to collect and condense the vapors, similar to classical distillation
  • Vacuum pump
  • Recirculating chiller or other cooled condenser ( In the case of the EcoChyll X1,  a chiller with no tank, no coolant liquid, and which achieves its setpoint temperature in just one minute!)

Classical Distillation:

  • Routine Separations 
  • Routine Purifications
  • Isolation of components

Rotary Evaporation:

  • Purification of Volatile or Temperature-Sensitive Compounds
  • Laboratory Synthesis in Sensitive Environments (synthesis of compounds with low boiling points)
  • Chemistry and Biochemistry 
  • Routine Separations 
  • Routine Purifications
  • Isolation of components


To sum things up, while classical distillation is cheaper to set up, and has less chances of running into technical problems (due to the simplicity of its setup), the practical advantages offered by rotary evaporation outweigh those of classical distillation. 


Rotary Evaporation 1 – 0 Classical Distillation

Tips and Tricks to Avoid Rotary Evaporator Glassware Implosions

When using your rotary evaporator, you are at a constant risk of glassware implosion. In this blog post, we’ll go over the different reasons why glassware implosions occur, the different dangers that are involved, and the different mitigative measures that you can undertake to prevent or reduce the risk of glassware implosions.

Why does rotary evaporator glassware implode?

Using vacuum with your rotary evaporator comes with a significant set of advantages, but if we were to list the disadvantages, one stands out: Glassware implosion. Besides throwing your samples down the drain, all over the wall, and all over you (Wear your PPE), implosions can result in projectiles of glass shards. The risk of implosion is directly proportional to the increase in vacuum: the higher the vacuum, the higher the chance of your glassware turning into a gnarly lab accident. The risk is exponentially increased when glassware is damaged. 


How to prevent glassware implosion


1-Checking Your Glassware for Cracks and Signs of Wear: 

You should routinely inspect your glassware for damage before every rotary evaporator run, and you shouldn’t use it if it’s visibly damaged. Look for cracks, chips, and scratches.  If your glassware isn’t safety coated you could always use filament tape in a crisscross pattern, which will help keep the different pieces of glass together in case of both implosions and explosions. Mesh or netting can also be applied for a similar effect.


2-Choosing the Right Glassware:

When choosing glassware, you should make sure that it is designed to withstand vacuum. And while certain rotary evaporators come with the option of safety-coated glassware, it’s always better to stay on the safe side, and double check the specs yourself. You should also bear in mind that evaporation flasks aren’t usually safety coated given the high bath temperatures that they need to withstand that could degrade the plastisol coating.


3-Using a Fume Hood:

While certain applications force you to run your rotary evaporator under a fume hood, you might want to consider that option to mitigate the risks presented by imploding glassware. You’ll want to keep the sash closed at all times, which will make it difficult to control and operate your rotary evaporator.


4-Increase the Vacuum Slowly:

An incremental increase in vacuum during your operation comes with a solid set of advantages, like decreasing the risk of bumping and foam formation, and a decreased risk of glassware implosion.

Tips and Tricks to Speed Up your Rotary Evaporation Process

In rotary evaporation, as in a lot of other things happening in your lab, time is of the essence. Maybe you need those APIs purified ASAP, or maybe your clients needed that ethanol removed from the cannabis they sent you yesterday. Bottom line is a rotary evaporator can only spin so fast, but we got your back. In today’s blog post we’ll give you a few tips and tricks to speed up your rotary evaporation process.


Increase your Vessel Size

It might  sound counterintuitive to use a vessel that is considerably larger than your sample size. However, increasing your vessel size is the way to go if you’re aiming for a more efficient process. A larger vessel means an increased surface area, which means that a bigger portion of your flask will be in contact with the water in the water bath, which paves the way for a quicker and more even heating process. At the same time, using a large vessel also means that the sample inside of the flask is exposed to more air, making evaporation more efficient!


Increase your Vacuum Level

As discussed in one of our previous blog posts, using a controllable vacuum source gives you the luxury of adjusting the pressure with surgical pressure, thus providing you with your desired evaporation rate. Variating the pressure (increasing it to be more specific), will decrease the pressure, and thus make your process faster. And while this is generally true, you need to avoid a few pitfalls, like bumping and foaming. A sharp decrease in pressure can also lead to a hasty evaporation, not allowing the solvent to evaporate properly. The uncondensed vapor might end up inside of the vacuum pump, which is undesirable to say the least. Oh, and did we mention that sharp drops of pressure in your flask might make it implode?


Increase your Bath Temperature

This one’s pretty straightforward: a higher bath temperature means a higher rate of evaporation, and a more efficient process. Just make sure that your sample can handle an increased temperature without any side reactions occurring, do your best to avoid bumping, and follow the rule of 20 to avoid too much solvent vapor formation.


Increase your Rotation Speed

Last but not least, increasing the rotation speed of your evaporation flask. To better understand how this works, we need to take a closer look at the two main functions achieved by rotating the flask: It improves the heat transfer from the water bath to the solvent and the flask, and it increases the evaporation rate by increasing the surface area of the liquid inside of the flask. However, reaching too high of a speed can lead to the sample being pressed against the sides of the flask, thus greatly reducing the efficiency of the process. You want to aim for 250-280 rpm to reach optimal turbulence.

How to Prevent Foam Formation and Bumping in your Rotary Evaporator

It is a common occurrence for samples being evaporated in a rotary evaporator to foam up, or starting bumping. This usually leads to sample loss, and possibly contamination. Foaming occurs when the sample’s surface tension decreases, leading to the production of bubbles. Bumping however refers to the sudden and vigorous release of vapor bubbles from the liquid phase, which can result in the sample splattering or even ejecting from the evaporator flask. Both situations can be problematic as they may lead to sample loss, reduced efficiency, or potential hazards. In this blog post, we’ll discuss a few steps you can take to mitigate the risk of foaming and bumping.


Reduce your sample’s concentration:

Foaming can occur if your sample is too concentrated. Diluting it with an appropriate solvent can help reduce foaming tendencies.


Adjust the vacuum pressure:

Lowering the vacuum pressure can significantly decrease the risk of bumping. You’ll want to ensure that the vacuum level is set correctly based on the sample’s boiling point to maintain a controlled evaporation process. As a rule of thumb, you’ll want to go slow by starting with  little vacuum, and gradually decreasing the pressure while visually inspecting your sample to make sure no bumping occurs.


Use an appropriate flask size:

Make sure that the flask size you’re using can comfortably fit your sample. This will prevent both foaming and bumping. You want to avoid overfilling your flask.


Use anti-bumping agents:

Glass beads and boiling chips can provide your sample with a nucleation site for bubble formation which ultimately reduces the risk of bumping.


Control the heating rate:

Just like the vacuum pressure, you want to keep a tight control of the heating rate of your sample. Gradually increase the temperature to avoid the  formation of large bubbles. A slower, more controlled heating process promotes gentle evaporation.


Optimize solvent selection:

Different  solvents have varying tendencies to foam or bump. Selecting a solvent with lower foaming characteristics or employing an appropriate solvent mixture can mitigate these issues.


Use Personal Protective Equipment (PPE):

As always, safety first! Even if you follow all the aforementioned steps, surprises still happen. Make sure to don your lab coat, gloves, and safety goggles to protect yourself in case of splattering or sample ejection.


There you have it! Next time you use your rotary evaporator, make sure to follow these steps for a foaming-free bumping-free process. Stay tuned for more!

Dry Ice: The Phantom Menace

Years after “Star Wars: Episode 1 – The Phantom Menace ” was released, George Lucas revealed that the title was a reference to Palpatine concealing his identity as an evil Sith Lord behind the façade of a good-willing public servant. And while dry ice slurries aren’t nearly as evil as Sith Lords, they do pack a few “evil” disadvantages that we’ll discuss in today’s blog post (keep reading all the way for a little surprise at the end of the blog).

Rotary evaporators are widely used in chemical and biological laboratories for distillation, solvent removal, and concentration of samples. One of the techniques employed in rotary evaporation is the use of dry ice slurries to maintain low temperature during the process. However, this seemingly routine procedure can pose serious safety hazards if not handled correctly.

A director at BMS recently noted the safety concerns that arise from the use of dry ice. As experienced scientists, we understand the potential risks of exploding condensers when water builds up in the cold finger and is not emptied and/or mistaken for acetone. The resulting rapid expansion of the slurry can lead to shattered condensers, posing the risk of physical injury to the scientists.

Exploding condensers are a significant issue that is not adequately addressed particularly in university Labs. Injuries can range from Minor cuts to serious lacerations that require medical attention. According to a report published by the Centers for Disease Control and Prevention (CDC), from 2001 to 2018 there were 2578 reported lab associated injuries involving rotary evaporators with 20% of these injuries resulting from shattered glassware.

The report also revealed that rotary evaporators were the second most common equipment involved in lab-associated injuries, after pipettes. The most common type of Injuries associated with rotary evaporators were cuts, punctures, and abrasions, with the hand being the most frequently affected body part. In addition to physical injuries, exploding condensers can also lead to equipment damage and downtime, negatively impacting productivity, research progress, and causing delays. Replacing damaged or broken equipment is often costly, and the unavailability of spares can further exacerbate the situation.

To mitigate these risks, it is crucial to ensure that proper training and education are provided to scientists who use rotary evaporators. This includes educating lab personnel on the correct use of the dry ice/acetone slurries, the importance of monitoring for water build-up in the cold finger, and appropriate disposal of the mixture after use. The use of protective gear such as gloves and eye protection should be mandatory to minimize the risk of physical injury.

Expanding on the negative impact of damaged or broken equipment due to exploding condensers, it is essential to highlight the financial cost that can be incurred. Replacing a damaged or broken condenser can be an expensive affair, and in many cases, there may not be any spares readily available in the lab. This can result in a significant delay in replacing the broken part, which can negatively impact productivity and research progress. Even if the replacement part is ordered immediately, it may take several days or weeks to arrive, which can be a major setback for ongoing experiments.

Lab guidelines and procedures should be established to ensure that all laboratory personnel are aware of the risks associated with dry ice/acetone slurries and the necessary precautions to prevent accidents and injuries. Spare parts should be readily available to facilitate the timely replacement of damaged or broken equipment.


In the style of master Yoda:

Widely used in chemical and biological labs, rotary evaporators are, hmmm. For distillation, solvent removal, and concentration of samples, they are employed, yes.

One technique, dry ice slurries, is used to keep temperatures low during the process. Safety hazards, however, can arise if not handled correctly, hmmm.

A director at BMS, safety concerns recently noted. Potential risks of exploding condensers, we understand. When water builds up in the cold finger and is mistaken for acetone or not emptied, rapid expansion of the slurry can lead to shattered condensers, and physical injury to the scientists, posing a significant risk, hmmm.

Not adequately addressed, exploding condensers are, particularly in university labs. Injuries, they can cause, ranging from minor cuts to serious lacerations requiring medical attention. A report by the CDC revealed 2578 lab-associated injuries involving rotary evaporators from 2001 to 2018, with 20% resulting from shattered glassware. The second most common equipment involved in lab-associated injuries, they were, after pipettes.

Cuts, punctures, and abrasions, the most common type of injuries associated with rotary evaporators were, with the hand being the most frequently affected body part. Equipment damage and downtime, they can also lead to, negatively impacting productivity and research progress, and causing delays.

To mitigate these risks, proper training and education are crucial for scientists who use rotary evaporators. Educating lab personnel on the correct use of dry ice/acetone slurries, monitoring for water build-up in the cold finger, and appropriate disposal of the mixture after use is essential. The use of protective gear such as gloves and eye protection should be mandatory to minimize the risk of physical injury.

Expanding on the negative impact of damaged or broken equipment due to exploding condensers, essential it is to highlight the financial cost that can be incurred. An expensive affair, replacing a damaged or broken condenser can be, and in many cases, no spares readily available in the lab there may be. Result in a significant delay in replacing the broken part, this can, productivity and research progress negatively impacting. Even if the replacement part is ordered immediately, several days or weeks to arrive it may take, a major setback for ongoing experiments, this can be.

Lab guidelines and procedures should be established, to ensure that all laboratory personnel are aware of the risks associated with dry ice/acetone slurries, and necessary precautions are taken to prevent accidents and injuries. Spare parts should be readily available to facilitate the timely replacement of damaged or broken equipment, hmmm.

Don’t Worry About the Dry Ice Supply Chain Going Dry

Don’t worry about the dry ice supply chain going dry – with Ecodyst

If you’ve been keeping up with logistics news, you might have heard of the dry ice supply chain,  and how it’s taken a significant hit during the COVID-19 pandemic: with vaccines requiring temperatures as low as -70°C during transport and storage, the demand for a constant supply of dry ice really put a strain on its supply chain. On top of that, the drop in oil prices didn’t help either: Oil refinery plants produce a lot of CO2, which is then used in the production of dry ice. When oil prices dropped, production went down, and in tandem with it, dry ice production. 

Dry ice is also used in food processing facilities, which includes but isn’t limited to wineries, meat processing facilities, and bakeries. It helps maintain critical temperatures which reduces spoilage during production, slows yeast growth which also delays fermentation, and inhibits the growth of different bacteria. However, the rapid and reproducible freezing of small samples isn’t the only use of dry ice: if you’re operating a rotary evaporator in your lab, you need a good coolant for your solvent to vaporize properly inside of the rotary evaporator. With the dry ice supply chain going dry, this might be an issue. 


No dry ice and no coolants to replace with the Ecochyll X1 and Hydrogen

Traditionally, recirculating chillers have been the go-to for most labs dealing with dry ice shortages. However, chillers come with a prominent set of draw backs. First of all, they take almost forever to get cold (anywhere between 30 minutes to an hour), their cooling power decreases rapidly at lower temperatures, so achieving certain temperatures requires extremely powerful chillers with a substantial price tag, and they’re quite heavy and bulky. And they need a significant amount of coolant liquid, which is rarely water due to its relatively high freezing temperature (that and the risk of the inside of the chiller freezing up). 

The Ecochyll X1 and the Hydrogen by Ecodyst both bypass all these drawbacks.  

“Since we switched to the EcoChyll X1, we can now avoid the use of dry ice for evaporating compounds. Sometimes there is no more dry ice in the building, and so that accelerates our research quite a bit. We don’t have to wait for dry ice to arrive, we can just keep working.” -Vincent Lindsay, Assistant Professor at NCSU

Here’s a bit more info on the Ecochyll X1 and the HYDROGEN

Ecochyll X1 Hydrogen
Tankless Cooling System Shortens run times
Cools to -10°C in 1 min and -40°C in 5 min Cools to -10°C in 1 min and -40°C in 5 min
Footprint under 1 ft2 0.1 m2 Reduces electricity consumption by 50%
No dry ice, no coolants to replace Smaller footprint than a rotovap and chiller
Virtually no maintenance  Eliminates the need for all coolants and dry ice

The Importance of Proper Vacuum for Rotary Evaporation

Using a vacuum source with your rotary evaporator comes with a significant set of advantages, like making your processes safer, more efficient, cleaner, and overall, easier. In this blog post, we’re going through all the reasons why owning a rotary evaporator is typically paired with using a vacuum source (either built-in or a vacuum pump).

Depending on the rotary evaporator you’re using, you might already have a built-in vacuum controller and you’ll only need to add a vacuum pump. However, if this isn’t the case, you’ll need to invest in both a pump and a manual (or digital) controller. Controllers don’t come cheap, but there are a few ways to decrease your cost (That we’ll discuss in a future blog post – stay tuned!).  

Controllable vacuum sources allow you to adjust the pressure with surgical precision, providing you with the desired evaporation rate. An increase in evaporation rate can therefore be achieved without having to upscale your bath’s temperature, which will allow you to achieve evaporation rates previously unattainable using a bath alone. Using a vacuum source also leads to improved solvent-product separation thanks to the controlled and even evaporation rate. It also decreases the risk of bumping (the formation of bubbles due to hasty boiling of samples; This can lead to your sample splashing out of the flask.). 

In regard to safety, using a vacuum source mitigates many risks. The decrease in boiling point of certain temperature-sensitive compounds reduces the odds of them reacting in your mixture. By reducing the pressure inside of the flask, and in tandem with it, the boiling point of your solvents, you can remove high boiling solvents in a quicker (we’re talking a few minutes, or even seconds) and safer manner. Inherently, you can work at lower bath temperatures, and use water instead of oil in heating baths. This is a safer option since using oil can leave behind residues in your evaporation flask which constitutes a fire hazard in the presence of flammable gas vapors. 

To sum it up, vacuum makes your processes safer, cheaper, and even easier (specially in cleaning – ever tried cleaning up oil off of your machine?).