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?).  

Setting the Right Rotational Speed for your Rotary Evaporator

When operating a rotary evaporator in your lab, you want to make sure that you’re being as efficient as possible. One of the main factors to be considered is the rotational speed of your rotary evaporator, and while it might seem like maxing it out is your best option, it might not always be the case. You wouldn’t want things to spin out of control now, would you? Some of the factors that you need to keep in mind when operating your rotary evaporator at its upper rotational speed is mechanical damage to your equipment caused by high speeds, and the decrease in evaporation rates beyond said speeds. And while certain studies postulate that the optimal speed lies somewhere between 250 to 280 rpm, it isn’t truly a definite rule of thumb. In this post, we’ll discuss the factors you need to take into consideration when setting the rotational speed of your rotary evaporator to make the best out of your processes. 


High Speeds and Potential Equipment Failure

High speeds are synonymous with an increased risk of equipment damage, mainly in two forms:

  • Vibratory forces which increase the wear and tear of the evaporator
  • Mechanical problems with the evaporator

Studies have shown that there is a linear relationship between mechanical failure and higher rotational speeds. Another thing worth noting is the increase in spillage risk due to the higher turbulence in water baths when operating at higher speeds. 


High Speeds and Evaporation

The rotation of the flask in a rotary evaporator leads to an increase in the surface area of the liquid inside of the flask, which increases the evaporation rate. The rotation also leads to an increase in the agitation of the liquid in the water bath. This improves the heat transfer to the flask, and the solvent. Both of the aforementioned factors depend on the rotation of the flask. Intuitively, one would think that an increase in the rpm of the evaporator would result in quicker evaporation, but this applies only to a certain degree. A study by Buchi showed that at rates above 400 rpm, the rate of evaporation started decreasing. The sharp increase in centrifugal forces eventually leads to the particles inside of the flask pressing up against the walls, decreasing the turbulence and eventually the evaporation rate. 

Simply put, you want to maximize the turbulence to achieve the highest evaporation rate. This will require you to factor in the flask size, the fill level (make sure to minimize the risk of both foaming and bumping to avoid contaminating your sample), the solvent, and sample consistency. 

One last thing you want to avoid  is any liquid sealing off your vapor tube. This could lead to the formation of a bubble that pushes the liquid up the vapor tube, contaminating the collection flask almost instantaneously. 


Optimal Rotation Speed

While 250 to 280 rpm works best for most rotary evaporators, some of them operate better at other speeds. This is particularly true when considering different sizes of rotary evaporators; a larger rotovap will almost always have a lower ideal speed (and lower maximum speed) than a smaller rotary evaporator of the same brand. Similarly, flask size will play a role in the ideal rotation speed as well, with smaller flasks meriting a higher rotation speed. The takeaway: read your user manual, and find the sweet-spot between speed and equipment wear. 

NIRvana Sciences Purchases EcoChyll X1 Rotovap Chiller

RESEARCH TRIANGLE PARK, NC, May 1, 2022 – NIRvana Sciences, Inc., the leading developer of synthetic bacteriochlorins and chlorins, today announced that it is purchasing an environmentally friendlier chiller for its rotovap system from Ecodyst, a local company in Apex, North Carolina.

Chris MacNevin, VP of Operations, said “We recently retrofitted one of our existing rotovaps with the Ecochyll X1 chiller unit and are very happy with its performance. A simple flip of the switch and the chiller is ready to go in minutes. It’s great to be free from the hassles of dry ice – no more constant refilling of the trap during solvent collection. So far it has worked well with all typical solvents with no noticeable solvent pass through. Convenient temperature control also allows for removal
of water without excessive frost buildup. Thanks to George and the team at Ecodyst for putting together a great product!”

About NIRvana Sciences
NIRvana Sciences is a spin-out from North Carolina State University with a mission to commercialize red and nearinfrared fluorescent dyes and associated probes and beads with narrow spectral properties for use in life science applications. In addition to support from NIH, NIRvana has also received support from angel investors in North and South Carolina, North Carolina Biotechnology Center (NCBC), NC IDEA and Blackstone Entrepreneurs Network. NIRvana facility is located at Alexandria Innovation Center in Research Triangle Park, NC USA.


Source: NIRvana Sciences

North Carolina State University Case Study

EcoChyll X1 & Hydrogen accelerating organic synthesis R&D at North Carolina State University.

NC State Case Study Brochure

The Rule of 20: setting the right temperature for your rotary evaporator

You just bought your rotary evaporator, you set it up on your benchtop after making sure to follow the manual instructions word for word. Everything’s all set and you’re ready to get some work done with your evaporator. And then it hits you: What temperature should you set your rotary evaporator to? Enter the “Rule of 20”, AKA the “20/40/60 Rule” AKA the “Delta 20 Rule”. 


The Theoretical How

In a nutshell, the Rule of 20 states that the temperature of your coolant should be at least 20 lower than the vapor’s temperature, and that your bath’s temperature should be 20 higher than the vapor temperature or boiling point your are trying to reach. Let’s say that the boiling temperature of your substance is 30. You’ll need a coolant temperature of 10 and a bath temperature of 50 to be operating under optimal conditions. 


The Why

By following the Rule of 20, you’re trying to find the perfect balance between energy usage and process efficiency: Higher bath temperatures merged with lower coolant temperatures increase the distillation’s efficiency. But there’s a catch: the higher the temperature of your bath and the lower your coolant temperature, the more energy you end up spending. This means that at a certain point, investing more energy into your process won’t be impactful on the overall efficiency of the process anymore. 

The Rule of 20 bypasses this issue by ensuring an efficient distillation. 

You should keep in mind that in certain scenarios, like working with heat-sensitive compounds, you might be forced to keep your bath’s temperature at levels lower than the one advise by the Rule of 20.


The Practical How

Now that you’re all set, it’s time to evaporate some solvents! In certain scenarios, and with a bit of luck, you might be able to apply the 20/40/60 rule literally: Simply set your bath temperature to 60, your coolant to 20, and your vapor temperature to 40 using your vacuum controller. By applying vacuum and reducing the boiling point, you can use the same temperature settings for most common solvents. We thought we’d save you some time: you can find the vacuum pressures of some common solvents below. 

Solvent Boiling Point (°C) Solvent
Acetic Acid 118.0 Ethyl Acetate
Acetic Acid Anhydride 139.0 Ethyl Ether
Acetone 56.3 Ethylene Dichloride
Acetonitrile 81.6 Ethylene Glycol
Benzene 80.1 Heptane
iso-Butanol 107.7 n-Hexane
n-Butanol 117.7 Hydrochloric Acid
tert-Butanol 82.5 Methanol
Carbon Tetrachloride 76.5 Methylene Chloride
Chlorobenzene 131.7 MTBE
Chloroform 61.2 Pentane
Cyclohexane 80.7 Petroleum Ether
Cyclopentane 49.3 iso-Propanol
Dichloromethane 39.8 n-Propanol
Diethyl Ether 34.6 Pyridine
Dimethyl Acetamide 166.1 Tetrahydrofuran
Dimethyl Formamide 153.0 Toluene
Dimethyl Sulfoxide 189.0 Trifluoroacetic Acid
Dioxane 101.0 Water
Ethanol 78.3 Xylene

While the rule of 20 is a good rule of thumb for most evaporative procedures, there is one aspect where it doesn’t hurt to overshoot: cooling. There is no downside to having the coolant even colder than 20 below the vapor temperature, and in fact it can help improve evaporation rates to do so. This increases solvent recovery, making your process as efficient as possible.  This is where chillers come in, but there’s a trick: chillers lose cooling power as they operate at colder temperatures due to less efficient heat transfer. Enter EcoChyll: by pumping refrigerant directly through the condenser coils from the compressor, the EcoChyll gets colder much faster, and can maintain very low temperatures better than what would be considered a suitably sized chiller hooked up to a rotary evaporator.




To Fume Hood or not to Fume Hood: Should you use a Fume Hood with your Rotary Evaporator?

Rotary evaporators can be spotted in labs under fume hoods or directly on benchtops. While both options are valid, there are multiple factors that need to be taken into account when deciding whether to use a fume hood or not. This blog post puts everything on the table (or benchtop) to help you answer the age-old question: to fume hood or not to fume hood?

1-Using the Right Equipment

We know, it’s an obvious one, but if your set up is too big to fit under the fume hood, you won’t be able to use it. Your choice of hood usually boils down to the amount of space available in your lab: if your condenser is vertical, you will probably need a larger fume hood as compared to diagonal condensers that are more “space-friendly”. Both ways, safety always comes first, so we’ve compiled multiple criteria to help you make the right choice when deciding whether or not to purchase a fume hood.


Implosions are most likely to occur if your glassware has cracks or fractures in it. When the glass is put under different stressors, it’s prone to break, which might lead to injury. In that case, it is advised to keep the sash closed at all times.


Some applications of your rotary evaporators come with a risk of explosion; this includes but isn’t limited to the use of different chemical mixtures that carry a high risk of explosion when put under certain conditions. For instance, multiple reports have emerged recording the presence of azide with the use of halogenated solvents leading to explosions shattering the glassware of rotary evaporators.

If an explosion was to occur, bystanders would be at risk of exposure to chemical splashes and being hit by flying glass shards. Using your rotary evaporator with your fume hood’s sash always closed is one of the easiest ways to mitigate the risk of different injuries caused by an explosion.

4-High-Temperature Applications

Another reason why you might consider getting your rotary evaporator a fume hood is high temperature applications. Say you’re using an oil bath and you’re heating it to temperatures at or above 100°C to perform a high-temperature evaporation; leaving it unattended might pose a prominent safety concern. You might be wondering what the best way is to mitigate that risk, and you guessed it: fume hoods.

5-Health Risks due to Fumes

Rotary evaporators should be used in well-ventilated areas. Removing volatile solvents is not a risk-free process: sometimes volatiles escape, and if present in high concentrations, might lead to explosions, irritation, and/or different respiratory illnesses. Sometimes, proper ventilation might not be accessible in your lab. In that case, once again, fume hoods are the answer.

It’s worth mentioning that some applications of your rotary evaporator might lead to the generation of toxic fumes or vapors. In that case, no matter how well ventilated your lab is, fitting your equipment under a fume hood becomes a necessity.

Getting the Job done without a Fume Hood

For whatever reason, getting a fume hood for your lab might not be an option. However, compromising your safety isn’t. That’s why we added a couple more alternatives to using a fume hood that provide you with the protection and ventilation you need to carry on your work in your lab worry and risk free.

1-Building a Safe Environment

Building a safe environment starts with you donning the right Personal Protection Equipment (PPE) if handling hazardous materials. Having the proper measures implemented inside of your lab if operating in special environments is also worth considering. For instance, certain applications should be carried out in labs that have preexisting built-in ventilation systems, and that are fully explosion proof.

2- Using an Enclosure instead of a Fume Hood.

Enclosures can be a great alternative to using a fume hood in your lab when trying to minimize exposure to fumes and vapors. It is worth mentioning that not all enclosures provide protection against both vapors and shattered glassware/ splashes,


Fume hoods serve one main purpose: minimizing exposure to the different risks you might be exposed to when using your rotary evaporator, namely noxious vapor and fumes, and flying shards of glass caused by implosions and explosions. Other options to consider when fume hoods are not available are either using an enclosure, or carrying out your experiments in a pre-made special environment.

Solvent Recovery vs Distillation: Which is Best?

Solvent recovery and distillation are critical processes in a range of industries. Both processes are used to separate and purify elements meaning they are helpful means of recovering a range of chemical components. This article will detail both processes and how they measure up against one another.

What is Solvent Recovery

Solvent recovery or solvent extraction is a technique in which chemical compounds are isolated in accordance with their solubilities. Solvent recovery is employed in a range of industries from vegetable oils, perfume, food, cosmetics, pharmaceuticals, manufacturing, cannabis production and mining. Solvent recovery is important because it is used to isolate hazardous materials from sediments and sludge and separate the helpful components from the debris.

An example of this is solvent recovery in the petrochemical refining industry, where it is used to separate petrol by causing them to float to the top or sink to the bottom for easy removal.

Solvent recovery is also important in the hazardous waste industry as it decreases the levels of hazardous waste that needs to be treated. Solvent recovery does not damage the substance which is extracted, just separates the compounds. These compounds are then extracted to be used for a range of purposes according to the industry. Solvent recovery is a means of purifying elements and identify different chemical components.

Rotary evaporators use evaporation to gently and efficiently remove solvents from a range of sample types, including both organic and inorganic analytes and polymeric materials. The sample is heated whilst its boiling point is lowered by a vacuum which is formed by the rotary evaporator. This means that solvent recovery is possible at a much lower temperature.

What is Solvent Distillation?

Solvent distillation is the solvent separation involving application of heat to separate a mixture of liquid of two or more two or more substances. The solvent mixture is heated to boiling point and as a vapor its piped away to a new storage container in which is will cool and condense to an almost pure quality. This results in a distilled solvent which can be reused and wastage which can be disposed of accordingly.

Rotary evaporators are sometimes used in distillation applications as it is faster than traditional techniques as solutions are distilled under reduced pressure at a lower temperature, speeding up the process because of the larger surface area.

The Key Differences Between Solvent Recovery and Distillation

The key difference between solvent recovery and distillation is that solvent recovery purifies a substance whether it is in a solid or liquid phase whereas solvent distillation can only purify a substance in the liquid phase. This means that solvent recovery can be used for more applications and is a more cost-effective solution.

Rotary evaporators from Ecodyst can be used for both distillation and solvent recovery. If you would like to find out more about how we can help you, contact us today.

Understanding how Cold Traps are Used in Vacuum Applications

Cold traps are used to condense vapors present in vacuum applications into a solid or liquid state (excluding permanent gases). The main function of a cold trap is to ensure that there is no contamination inside vacuum applications. Whilst experiments are conducted, containers must sit airtight so no vapor can escape and no extra gas can enter the chamber and cold traps work to stop this.

How Does a Cold Trap Work?

Cold traps are usually made up of two parts, the bottom being a large, thick round tube with ground glass joints. The second is a cap that also has ground-glass connections. The length of the tube is selected so that the cap reaches about half the length.

Cold traps should be assembled so that the down tube connects to the gas source whilst the cap is connected to the vacuum source. This means that vapor phase condensate is unlikely to move up the tube.

Cold traps condense incoming vapors in the chamber to inhibit contamination. It is particularly useful for the removal of large quantities of liquid in freeze-drying.

Cold Trap Applications

Cold traps are used in applications in which the process is coming over in the form of a vapor and must be trapped. There is a range of different traps that can be tailored to the chemical composition of the process.

Some processes have gasses that travel in a vapor form and can easily be trapped once rapidly cooled. This means that the vapor condenses and the condensation can be collected in the trap.

Cold traps are often used in applications that require low-temperature conditions via evaporators such as distillation and condensation. In these applications, the cold trap contains a freezing mixture of dry ice or a coolant and acetone.

Cold Traps and Rotary Evaporators

Cold traps play a critical role in traditional rotary evaporators as it traps gas on a cooled surface in a coagulated manner. The cold trap is placed in between a vacuum vessel and a pump for trapping oil vapor or adsorbing gas. The cold trap is lined with a lead gasket and connected to the vacuum pump and suction container.

The cold trap adsorbs heat from the condenser, keeping the temperatures low, and when gas passes through the water vapor and other gases solidify on the condenser. This then increases the degree of vacuum.

Why Ecodyst’s Revolutionary Technology Replaces Cold Traps

Traditional rotovaps used cold traps that require material such as liquid nitrogen or anti-freeze to cool them. However, Ecodyst’s new revolutionary technology uses continuous cooling, eliminating the need for excess, expensive, and energy inefficient cooling technology.