1

Lab Manager’s

Product Resource Guide: Evaporators

Rotary Evaporators: Must Have Features 2 Angelo DePalma PhD

Choosing the Best Evaporator For Your Application (Video) 4 Lab Manager

Tips for Choosing an Evaporator for Your Lab 5 Ryan Ackerman

Reducing, Distilling, Recycling and Concentration 7 Angelo DePalma PhD

Selecting a Vacuum Pump for Rotary Evaporation (Video) 8 Lab Manager

All-in-One Versions and Other Options to Enhance Efficiency 10 Mike May PhD

Nitrogen Evaporators: Making Concentration Easier & Greener 12 Mike May PhD

Evaporator Product Finder 15 Lab Manager

Manufacturer List 15

2

Rotary Evaporators: Must-Have Features Rotary evaporators, or “rotovaps,” may be found wherever processes require sample concentration or . By Angelo DePalma PhD

Rotary evaporators are standard laboratory equipment found in nearly all laboratories. Chemical, pharmaceutical, food, and environmental industries are the most common users, but rotary evaporators, or “rotovaps,” may be found wherever processes require sample concentration or solvent distillation.

All rotary evaporators include a heating bath, , collecting vessel, and rotating sample or distillation flask. BUCHI Corporation (New Castle, DE), a leading manufacturer of rotovaps, sells a large number of those simple units to academic and even industrial labs. But another world of rotary evaporation exists for laboratories that value application versatility, automation, and connectivity.

“Our largest-volume market has been and remains pharmaceuticals, and they’re willing to pay for a high degree of automation, for many features that go beyond simple rotovaps,” says Jason Wagner, VP of marketing at BUCHI. “But there’s still a big market for stripped-down, no-frills models.”

3

A “full system” has a chiller to replace the use of cold tap water in the condenser unless dry ice is readily available. In place of the simple aspirator or house vacuum you may now be using, you could enjoy the benefits of a real vacuum pump, which is chemically inert and quiet. Worried about samples bumping into the condenser and collection vessel? A vacuum controller will solve that problem without the user having to give it a second thought.

Unlike with some laboratory products where purchasers must outsource upgrades and modifications, top rotovap vendors supply all the necessary components.

Since modern rotary evaporators operate at up to 5 L at benchtop scale and at 20 to 50 L for industrial models, general solvent recycling becomes an attractive alternative to dedicated distillation systems. Low-temperature condensation traps even volatile like ether and methylene chloride, while high vacuum enables recycling of polar aprotic solvents like or distillation of essential oils.

Every user of rotary evaporators has experienced bumping. Vacuum controllers virtually eliminate such mini-disasters by allowing a vacuum gradient. “That’s where automation really comes in,” Wagner says. “The controller and AutoDest sensor measure whether the condenser is heating and adjust vacuum accordingly.” Similarly, a foaming sensor can tell whether the distillation is getting out of control. “And all the user has to do is say go.”

The wide variation in features and price and the low potential dollar entry point for rotary evaporator acquisition are somewhat unusual in the world of laboratory equipment. Yet despite the lingering fondness for simple rotovaps, nearly every laboratory can benefit from automation, says Thomas Ketterer, head of application support at IKA Works (Staufen, Germany). “The reasons are enhanced safety, the capability for unattended operation, consistency of conditions, and results.”

A call for simplicity?

Jim Dawson, president of Heidolph North America (Elk Grove Village, IL), believes that automation may be overhyped. “Researchers want to be able to run their processes uninterrupted but to get involved easily if the need arises. Chemists are hands-on, highly visual types of researchers. They may wish they could walk away from what

4 they’re doing completely and still achieve the desired result, but they don’t do that in practice. They want simplistic automation, not something complicated. They want automated vacuum control and measurement, and want to know that when the evaporation is completed the flask will come out of the bath, but it has to be simple. And they don’t want to spend a lot of money on it if they don’t have to.”

The ability to have many options at varying price points is a hallmark of rotary evaporators. “Chemists don’t want to be boxed in to one level of sophistication; they want to pick and choose specific options and do that with an associated price as well,” Dawson says.

Choosing the Best Rotary Evaporator for Your Application

Join Linda the lab manager and her team as they explore what some of the features to consider when purchasing a new rotary evaporator for your lab.

 Watch Video

5

Tips for Choosing an Evaporator for Your Lab As it does with most lab instruments and equipment, the sample plays a major role in which evaporator will be best for your lab

How will sample type affect which evaporator is ideal?

The sample in question will play a key role in the evaporator setup. For example, if acids are being used, the system must be properly coated to prevent corrosion (especially on the pump), and will need proper ventilation. Solvents can damage rubber and plastic components, and should be protected against as well. Another important consideration is that different samples are condensed at different temperatures, and may require different cold traps: typically a -50°C cold trap is ideal for aqueous-based samples, a -85°C cold trap traps most solvents, and a -105°C cold trap is recommended for alcohols.

6

How are safety concerns addressed for evaporators?

Due to the nature of heating up aqueous samples, acids, and solvents, a variety of safety accessories can be used to ensure the safety of the operators. As glassware is under extreme pressure due to the vacuum pump as well as being heated, coated glassware can be used to ensure flasks don’t shatter during operation. Shields and protective hoods with ventilation can also help ensure operator safety. Some manufacturers offer advanced options, such as motorized lifts and shutoff procedures for power outages or if the heating bath goes dry.

What environmentally friendly options are available for evaporator usage?

For the condensing and collection of samples, many options exist. Condenser coils or cold fingers are generally paired with circulating tap water or dry ice. While these methods are adequate for the purpose, constant changing of water to prevent algae buildup can get wasteful, along with a constant need for dry ice. Many manufacturers now offer circulating chillers which can be attached to evaporators, allowing for highly efficient condensation without the waste associated with using tap water or dry ice.

7

Reducing, Distilling, Recycling, and Concentration. Rotary evaporators have for decades been staples in labs and industries performing chemistry

By Angelo DePalma PhD

Key applications include sample concentration, solvent recycling, extractions, and separation of solvent mixtures

In their simplest embodiment, “rotovaps” consist of a temperature bath, rotating flask, condenser, collection flask, and vacuum source. Solvent distills from the sample under the combined effects of heat and vacuum, and collects after condensation in the collector. Recovered single-phase organic solvents may be dried and re-used; binary, tertiary, or quaternary solvent mixtures are also re-used but may need adjustment for composition.

Water is the fluid of choice for the bath, but some laboratories use oils to reach heating temperatures of up to 180°C. Several choices are available for the condenser coolant. Until about 10 years ago, almost everyone used house water. Concerns over water consumption caused many labs to switch to a chiller to recirculate coolant into and out of the condenser coils. Chillers provide more precise cooling, greater control over

8 condensation, a greatly reduced environmental footprint, and are overall less expensive to use than water. High-efficiency trapping of low-boiling solvents is achieved with a “cold finger” charged with dry ice and acetone.

Vacuum options

Of all the rotovap options, vacuum is probably the broadest. At one time, water aspirators were the most common vacuum sources. That practice has gone by the wayside for the reasons given for water coolers and due to environmental concerns related to solvent vapors venting down the drain.

The next most common source is house vacuum, which is limited but inexpensive and reliable. Users typically insert a Woulff bottle or cold trap between the vacuum spigot and the rotovap, to trap volatiles that the condenser missed and protect the house vacuum system.

Increasingly, users employ vacuum pumps to achieve reproducible and rapid solvent removal. The vacuum must be applied carefully, however, to avoid bumping and foaming.

Traditionally, vacuum control was achieved by slowly closing a glass stopcock. Increasingly, users are turning to more sophisticated vacuum control, which Kristof O’Connor, product manager at Heidolph Brinkmann (Elk Grove Village, IL), describes as “probably the number-one improvement in rotary evaporators over the past two decades.” Control became necessary, he says, because “vacuum pumps are very stupid machines. They try to achieve as high a vacuum as they can, as quickly as possible, which often results in bumping and foaming.”

Lisa Sprenger, account manager at IKA Works (Wilmington, NC), agrees on the importance of vacuum control and the full and volume regulated distillation method implementations, and adds the following:

 Larger graphic displays with increased data storage capacity  Additional safety features to regulate heating baths and motor units  Implementation of full and volume- regulated distillation methods  Motorized lift systems  Clockwise and counterclockwise rotation of the distilling flask to increase speed and efficiency for powder drying applications

Newer rotovaps may incorporate thermocouple-controlled operation, in which a pump integrates with a controller and a thermocouple located in the vicinity of the condenser coils. As the coil temperature rises through heat transfer between the condenser and the evaporated solvent, the vacuum is bled out through valving to maintain steady

9 distillation. Another technique, known as “RPM” control, speeds or slows the pump’s inner workings to control the delivered vacuum.

Whereas valve control is generic, RPM control locks users into pumps from a single manufacturer. “Our RPM control pump only works with our precision controller,” Mr. O’Connor tells Lab Manager Magazine.

Coupled with software and solvent databases, vacuum control allows users to plug in bath temperature and solvent for ultimate fine-tuning of evaporation rate, to the point of allowing of multi-component solvents, followed by final drying.

“These features provide reproducibility, and make it easier and faster to optimize operating parameters,” Mr. O’Connor says.

An important new concept in laboratory rotary evaporation is systems integration. To put it simply, in such an arrangement, the main components of the evaporation solution--the evaporator, the vacuum pump, the vacuum controller, and the recirculating chiller--are fully integrated with respect to parameters and control. The benefits of such an integrated solution include: up to 75 percent reduction in energy consumption, reduced heat emissions in the lab, optimized distillation capacity, and increased process safety due to the connectivity of all the components. “Chillers that are not fully integrated with the entire evaporation system waste a lot of energy and generate heat between the distillation runs because they do not shut off automatically,” advises Michael Stern, director of marketing at BUCHI Corporation (New Castle, DE). “On the other hand, fully integrated systems provide many performance, safety, and sustainability benefits,” he adds.

Purchase factors

Potential purchasers should consider several vacuum and condenser cooling options before buying a rotovap.

Cooling method, which dictates the type of condenser used, should be decided based on the expected solvent load. More vigorous cooling is demanded for high volumes, rapid distillation, and very low-boiling solvents like ethyl ether.

Purchasers should consider whether automated, volume-dependent rotary evaporation is desired. This feature combines precise distillation with walk-away automation.

10

Selecting a Vacuum Pump for Rotary Evaporation Join Linda the lab manager and her team as they examine what features the best pumps can (and should) offer.

 Watch Video

All-In-One Versions and Other Options Enhance Efficiency and Safety

More options available than ever before By Mike May PhD

In 1950, the late biochemist Lyman C. Craig of The Rockefeller University developed a simple rotary evaporator. The first commercial version came from Walter Buchi in 1957. A rotary evaporator is a lab instrument that allows people to do chemical separation or purification by using heat and agitation—or stirring—

11 under vacuum. “You’ll find one in any chemistry lab,” says Jim Dawson, president of Heidolph North America (Elk Grove Village, IL).

As Jeff Reid, product specialist at BUCHI Labortechnik AG (Flawil, Switzerland), points out, “You can use a rotary evaporator to separate a solvent from a compound of interest.” He adds, “Solvent recycling is big as well.” This technology can also be used in other applications, such as crystallizing samples.

Evolving evaporators

“There used to be just a few configurations of rotary evaporators,” says Dawson, “but now there are more options—different configurations to choose from and more manufacturers.”

Enhancing safety is a key trend in this technology. “Many researchers want the ability to safely control a rotary evaporator outside the fume hood or away from the chemistry,” Dawson says. “This doesn’t mean a remote such as a TV remote, but a small wired operating panel that allows the chemist to control the process going on inside the hood at a safe distance.” He adds, “It basically helps to protect the scientist from the chemistry.” Still, chemists often want to watch the process. “Chemists still do lots with their eyes, like visualizing [whether] something is changing,” Dawson explains.

Beyond safety, users want very low maintenance. “All researchers now have to run at higher levels of productivity, and downtime has to be minimized,” Dawson says. “So price isn’t always the game.” He adds, “The keys are the total cost of lifetime ownership and productivity.”

All-in-one control

Beyond controlling a rotary evaporator from outside a hood, some users want additional control with the technology itself. When asked about recent trends, Reid says, “Researchers want a system where you can control all of the components—the chiller, the vacuum pump, and the rotary evaporator itself—together.” He adds, “An all-in-one system can save 75 percent in energy. In such a system, for example, the vacuum pump produces the needed level of vacuum and then holds it, instead of running continuously.”

Users can also build a system from various vendors and run them all from one controller. John Pollard, vice president of sales at BUCHI, says, “Our controller and some of our competitors’ controllers can control other brands, but you lose the green functionality.” When building a system from various components, for instance, the controller might display the vacuum but not turn off the pump when it reaches the

12 desired level. “It’s more automated when it all comes from a single manufacturer,” Pollard says.

An all-in-one system also enhances the simplicity of using a rotary evaporator, which Pollard says is near the top of the list among customer desires. “In an academic market, you could have 100 users of one rotary evaporator.” So that machine needs to be easy to use.

In some cases, the use is easy enough but, as Reid says, “The trick is to find the right parameters.” He adds, “So we provide those for the most common solvents.”

From the field

For a rotary-evaporator customer, two questions should be considered. First, will the rotary evaporator work as the manufacturer says it will? Second, if something goes wrong, will the customer have support to get it running again? “Chemists know things will go wrong,” Dawson says, “because they are using volatile chemicals and acids.”

Alfred Bacher, Ph.D., of the department of biochemistry at the University of California, Los Angeles, teaches lower-division organic laboratory courses and the upper-division inorganic/organometallic laboratory course. He says, “In all of these courses, we use rotary evaporators very heavily, particularly in the lower-division courses, because the solvents being used are flammable.” Based on working largely with undergraduate students, Bacher would like a range of improvements in rotary evaporators. For one thing, he’d like lower-cost versions because, he says, “The cost of the rotary evaporators is too high to be used in larger numbers in undergraduate laboratory courses.”

In addition, Bacher desires some design improvements. “Overall, the design seems to be very intimidating to many of my undergraduates,” he says. He’d also like the design to “allow for an easier disassembly of the setup for maintenance.” In fact, he’d like less maintenance overall. For example, he says the seals that connect the condenser unit with the motor are “not as robust” as they could be. Maybe, Bacher suggests, a rotary evaporator could include fewer joints in general to reduce the sources of leaks. For example, he says, “While I do understand why the receiving flask is attached with a ball joint, I feel it generates a significant problem as well because most round-bottom flasks used in the lab have normal ground glass joints.” Even adding a simple pressure gauge would be nice, Bacher notes.

Some problems can even be costly. As Bacher says, “The speed of lowering the assembly is too high in some models or a low point cannot be set to avoid the destruction of the vapor duct, which happens frequently in undergraduate laboratories.”

13

Nonetheless, Bacher realizes that many factors come into play in device design. So he describes his suggestions as “some of them being realistic, others probably not so much.”

Beyond the lab, rotary evaporators also appear in new markets. For example, some chefs use a rotary evaporator to distill liquids that they use over foods, like pouring on a high-tech reduction. The increasing simplicity of using this technology, such as the availability of all-in-one systems, should lead to even wider circles of use.

Nitrogen Evaporators: Making Concentration Easier and Greener When a scientist needs to concentrate a sample that’s in a volatile liquid— like acetone, acetonitrile, or methanol—a nitrogen evaporator can do the job.

By: Mike May PhD

14

Kelly Williams, product manager for nitrogen evaporators at Labconco (Kansas City, MO), says that nitrogen evaporators are typically used “to concentrate samples before analysis or to concentrate samples before a solvent exchange.”

How a scientist uses a nitrogen evaporator depends largely on the industry, says David Oliva, sales and marketing manager at Organomation (Berlin, MA). “For example,” he says, “our environmental laboratory customers might mainly use our equipment while conducting the 500-level EPA methods.”

At Pharmacore (High Point, NC), senior director of GMP analytical chemistry Mark Shapiro says, “We use this technology to evaporate large quantities of solvent to do cleaning verifications.” As a company that provides chemistry services—from custom organic synthesis to manufacturing of controlled substances—Shapiro and his team need efficient processes and instruments.

Tweaking the technology

A variety of changes keep improving nitrogen evaporators. As an example, Williams points out “advancements that have made nitrogen blowdown evaporation more convenient.” These include the addition of a dry block heater instead of a water bath. The latter, says Williams, “requires maintenance and generates condensation, leading to cross contamination.” In addition, she says that endpoint determination comes in handy with samples that cannot go to dryness but need to be concentrated to a specific volume for analysis. Williams says, “This frees end users up so they do not have to babysit their samples.” Last, she adds that mechanical vortex motion or placing samples at an angle to create vortexing action in the sample increases the rate of evaporation by increasing the surface area.

Other advances in the technology also benefit many scientists. Oliva says, “In my opinion, the most interesting advance in laboratory evaporation as a whole is the ability to recapture solvent in an efficient manner.” In part, state and federal regulations drive this advance, because today’s laboratories must be more environmentally friendly. As an example, Oliva says that Organomation makes solvent evaporators “capable of up to 97 percent solvent recovery.” He adds that these evaporators “for round-bottom flasks can be purchased with a nitrogen manifold option, which aids evaporations that will be going to dryness.”

For nitrogen evaporators specifically, Oliva sees flexibility as the biggest advance. He says, “While some products in the laboratory space are increasingly specialized for a specific application, customers demand that nitrogen evaporators can be utilized in a broad range of applications.” For example, some scientists want a device that works with different sample holders, such as vials or 96- well plates. That is available in existing devices.

For Pharmacore’s needs, Shapiro says that his existing nitrogen evaporator “does everything we need. It has variable speeds and temperatures.” If he could get an improvement, he’d like a valve on the nitrogen delivery line that slowly actuates once the lid is closed—instead of being completely

15 open right away. For now, he and his colleagues just close the lid on the evaporator and slowly turn on the nitrogen by hand.

The breadth of use for nitrogen evaporators means that the devices must work in different conditions. That can require variations in the technology. For instance, Oliva says, “If the nitrogen evaporator is being used with harsh solvents, I would extremely recommend a unit with acid-resistant coatings.” The right features and a little TLC can keep a nitrogen evaporator working for years.

Lab Manager Product Finder

Laboratory evaporators are used to prepare analytical and biological samples that need to be dry, as well as for solvent recovery in many labs.

Start searching for the perfect evaporator now.

 Get Started

16

Manufacturer List

Glas-Col is a worldwide leader in the field of laboratory products and industrial heating and mixing equipment. Recognized as an industry leader in quality, reliability, and flexibility, we offer the highest quality products with the highest level of customer support. We strive to provide products that are safe, efficient, reliable, and of the highest quality, and support our products with customer service which is timely, accurate, and fair.

Regardless of the field you work in, we are all striving for the same goal: to alleviate and fight diseases, to generate healthier food and to develop new innovative materials... in short: to enhance people’s health and living conditions. You do the research and we provide you with the necessary support.

KNF Neuberger, Inc. is a leading manufacturer of reliable oil-free laboratory vacuum pumps, systems, and controllers; liquid dosing/metering and transfer pumps; and rotary evaporators. All KNF laboratory products offer compact design, long service life, and dependable performance. Contact KNF Neuberger today to discuss your specific laboratory needs.

Buchi www.buchi.com Porvair Sciences www.porvair-sciences.com EYELA www.eyelausa.com Thermo Fisher Scientific www.thermoscientific.com Genevac www.genevac.com VACUUBRAND www.vacuubrand.com Hiranuma www.hiranuma.com Yamato Scientific www.yamato-usa.com IKA www.ika.com JEOL www.jeolusa.com Labconco www.labconco.com Organomation www.organomation.com

17