productivity handbook for industrial evaporation · productivity handbook for industrial...
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Productivity HandbookFor Industrial Evaporation
Get the most out of your application and improve your distillation rate by adjusting the relevant parameters.
Efficiency
Append handy accessories for extra convenience to gain time and increase comfort.
Comfort
Ensure the glass configuration is appropriate for the desired application, product and solvent.
Setup
Let the instrument work by itself with minimal user interaction and monitor the process remotely.
Automation
Improve your industrial evaporationTips and tricks for the Industrial Rotavapor® R-220 Pro
Achieve best results and performance of your application with handy expert advice. This interactive guide provides a wide range of general recommendations for your industrial evaporation as well as specific suggestions for the Industrial Rotavapor® R-220 Pro.
Applications Appendix
Setup description and choice ........................................2 Overview of glass configurations....................................3Descending and reflux assemblies.................................4Special assemblies and receiving flasks.......................5
Learn more
Distillation rate and calculation example.......................7 Influencing factors..............................................................8Effect of cooling..................................................................9Table of maximum distillation rates................................9
Learn more
Find out about integrated safety features or add further protection measures for special demands.
Safety
Built-in automation features...........................................10 Additional automation accessories..............................10
Learn more
Included safety features..................................................11 Additional safety add-ons...............................................11
Learn more
Further equipment............................................................12 Examples of customized items.....................................13
Learn more
Concentration Solvent recycling Solvent listDrying
2 ©Büchi Labortechnik AG 2017
The temperature of the heating bath (and particularly the difference to the vapor temperature) is crucial when it comes to efficiency. In terms of safety, various safety mechanisms exist related to the heating bath.
Heating bath
Several factors associated with the flask affect the distillation rate of the system and are hence important to optimize performance. Further, handy accessories facilitate flask handling and customized flasks are tailored to your needs.
Flask
The boiling point of the solvent depends on the pressure applied. Adjusting the vacuum results in altering the vapor temperature - a vital system parameter with effects on efficiency as well as several automation options.
Vacuum
In the condenser the vapor cools down and forms the condensate collected in the receiving flask. Cooling is an important parameter related to efficiency (distillation rate) as well as automation.
Condenser
The glass configuration is crucial in every concentration or purification process and careful consideration is one of the keys to good results. The glass configuration strongly depends on the desired application, the product to be distilled as well as the solvent. A number of different configurations are available, each designed to deal with common challenges in industrial evaporation.
Glass assembly
Setup: The right choice is key Quick and easy description of the Industrial Rotavapor® R-220 Pro
Learn about the major components of the Rotavapor® R-220 Pro. Using the correct setup for the intended application is the basic prerequisite to achieve best performance and maximum productivity.
Learn more
More on efficiency
More on efficiency More on efficiency
More on efficiency
More on comfort
More on automation
More on automation More on safety
3 ©Büchi Labortechnik AG 2017
Glass configuration
D
175 cm total
height
C
Type
Applicable for
Setup: Glass configurationVariety of glass assemblies for your needs
The choice of the glass configuration strongly depends on the desired application. There are basically two types of configurations: reflux and descending. Both come in different sub-variations, each designed for a specific pur-pose. Scroll over the versions below to learn more about their intended use and further benefits.
RefluxSpecifically designed assembly for distillations under reflux and high boiling solvents.
Low temperture coolingFor example dry ice is used as cooling agent.
Foaming samplesTendency to foam or bump during distillation.
Recrystallizations
System requirements
Applications
Solvent recycling
DescendingUniversal assembly for most standard distillations and low boiling solvents.
Reduced heightHeight restrictions for the instrument exist.
Low boiling pointHighly volatile solvents are used.
Drying samples
Concentration of samples
Reactions under reflux conditions
R
RC
4 ©Büchi Labortechnik AG 2017
D DB2 RD2 RBDB C
Interactive
Glass configuration
D2
175 cm total
height
C
Type
Applicable for
Setup: Glass configurationVariety of glass assemblies for your needs
The choice of the glass configuration strongly depends on the desired application. There are basically two types of configurations: reflux and descending. Both come in different sub-variations, each designed for a specific pur-pose. Scroll over the versions below to learn more about their intended use and further benefits.
RefluxSpecifically designed assembly for distillations under reflux and high boiling solvents.
Low temperture coolingFor example dry ice is used as cooling agent.
Foaming samplesTendency to foam or bump during distillation.
Recrystallizations
System requirements
Applications
Solvent recycling
DescendingUniversal assembly for most standard distillations and low boiling solvents.
Reduced heightHeight restrictions for the instrument exist.
Low boiling pointHighly volatile solvents are used.
Drying samples
Concentration of samples
Reactions under reflux conditions
R
RC
5 ©Büchi Labortechnik AG 2017
D DB2 RD2 RBDB C
Glass configuration
DB2
150 cm total
height
C
Type
Applicable for
Setup: Glass configurationVariety of glass assemblies for your needs
The choice of the glass configuration strongly depends on the desired application. There are basically two types of configurations: reflux and descending. Both come in different sub-variations, each designed for a specific pur-pose. Scroll over the versions below to learn more about their intended use and further benefits.
RefluxSpecifically designed assembly for distillations under reflux and high boiling solvents.
Low temperture coolingFor example dry ice is used as cooling agent.
Foaming samplesTendency to foam or bump during distillation.
Recrystallizations
System requirements
Applications
Solvent recycling
DescendingUniversal assembly for most standard distillations and low boiling solvents.
Reduced heightHeight restrictions for the instrument exist.
Low boiling pointHighly volatile solvents are used.
Drying samples
Concentration of samples
Reactions under reflux conditions
R
RC
6 ©Büchi Labortechnik AG 2017
D DB2 RD2 RBDB C
Glass configuration
DB
150 cm total
height
C
Type
Applicable for
Setup: Glass configurationVariety of glass assemblies for your needs
The choice of the glass configuration strongly depends on the desired application. There are basically two types of configurations: reflux and descending. Both come in different sub-variations, each designed for a specific pur-pose. Scroll over the versions below to learn more about their intended use and further benefits.
RefluxSpecifically designed assembly for distillations under reflux and high boiling solvents.
Low temperture coolingFor example dry ice is used as cooling agent.
Foaming samplesTendency to foam or bump during distillation.
Recrystallizations
System requirements
Applications
Solvent recycling
DescendingUniversal assembly for most standard distillations and low boiling solvents.
Reduced heightHeight restrictions for the instrument exist.
Low boiling pointHighly volatile solvents are used.
Drying samples
Concentration of samples
Reactions under reflux conditions
R
RC
7 ©Büchi Labortechnik AG 2017
D DB2 RD2 RBDB C
Glass configuration
RB
R
143 cm total
height
C
Type
Applicable for
R
Setup: Glass configurationVariety of glass assemblies for your needs
The choice of the glass configuration strongly depends on the desired application. There are basically two types of configurations: reflux and descending. Both come in different sub-variations, each designed for a specific pur-pose. Scroll over the versions below to learn more about their intended use and further benefits.
RefluxSpecifically designed assembly for distillations under reflux and high boiling solvents.
Low temperture coolingFor example dry ice is used as cooling agent.
Foaming samplesTendency to foam or bump during distillation.
Recrystallizations
System requirements
Applications
Solvent recycling
DescendingUniversal assembly for most standard distillations and low boiling solvents.
Reduced heightHeight restrictions for the instrument exist.
Low boiling pointHighly volatile solvents are used.
Drying samples
Concentration of samples
Reactions under reflux conditions
R
RC
8 ©Büchi Labortechnik AG 2017
D DB2 RD2 RBDB C
Glass configuration
R
R
163 cm total
height
C
Type
Applicable for
R
Setup: Glass configurationVariety of glass assemblies for your needs
The choice of the glass configuration strongly depends on the desired application. There are basically two types of configurations: reflux and descending. Both come in different sub-variations, each designed for a specific pur-pose. Scroll over the versions below to learn more about their intended use and further benefits.
RefluxSpecifically designed assembly for distillations under reflux and high boiling solvents.
Low temperture coolingFor example dry ice is used as cooling agent.
Foaming samplesTendency to foam or bump during distillation.
Recrystallizations
System requirements
Applications
Solvent recycling
DescendingUniversal assembly for most standard distillations and low boiling solvents.
Reduced heightHeight restrictions for the instrument exist.
Low boiling pointHighly volatile solvents are used.
Drying samples
Concentration of samples
Reactions under reflux conditions
R
RC
9 ©Büchi Labortechnik AG 2017
D DB2 RD2 RBDB C
Glass configuration
C
R
158 cm total
height
C
Type
Applicable for
R
Setup: Glass configurationVariety of glass assemblies for your needs
The choice of the glass configuration strongly depends on the desired application. There are basically two types of configurations: reflux and descending. Both come in different sub-variations, each designed for a specific pur-pose. Scroll over the versions below to learn more about their intended use and further benefits.
RefluxSpecifically designed assembly for distillations under reflux and high boiling solvents.
Low temperture coolingFor example dry ice is used as cooling agent.
Foaming samplesTendency to foam or bump during distillation.
Recrystallizations
System requirements
Applications
Solvent recycling
DescendingUniversal assembly for most standard distillations and low boiling solvents.
Reduced heightHeight restrictions for the instrument exist.
Low boiling pointHighly volatile solvents are used.
Drying samples
Concentration of samples
Reactions under reflux conditions
R
RC
10 ©Büchi Labortechnik AG 2017
D DB2 RD2 RBDB C
Using a reflux configuration with an open reflux valve, the condensate can therefore run out directly to the receiving flask avoiding potential flow back to the evaporation flask as is possible with the descending setup.
Second condenserThe descending assembly can be extended by an additional condenser. The second condenser acts as a post condenser and reduces emissions of low boiling solvents. Hereby, the distillation rate is not affected as the solvent is fully condensed in the first condenser.
Distillate coolerAs the vapor path indicates, the condensed solvent comes close to the hot vapor entering the condenser. This heats up the condensed solvent and may lead to solvents boiling in the receiving flask, particularly if the boiling point is close to ambient temperature. Hence, the distillate cooler cools down the potentially warm solvents.
High boiling solvents may condense in the expansion vessel due to the difference in vapor and ambient temperature. The condensed solvent may flow back into the evaporating flask and can cause a reduction of the distillation rate of up to 5%.
Setup: Glass configurationVariety of glass assemblies for your needs
Descending configurationThe descending glass configuration is applicable for most standard distillations. Due to its design, it is particularly suitable for low boiling solvents as well as for foaming and bumping products. Compared to the reflux configuration, the vapor path of a descending assembly is unidirectional and the condensate is clearly seperated from the entering hot vapor.
Reflux configurationThe reflux assembly is particularly designed for reactions under reflux (e.g. extractions or recrystallizations). In addition, the reflux configuration is preferred for high boiling solvents. The vapor condenses in the expansion vessel partially flowing back before it escapes to the receiving flask.
The descending setup is ideal for foaming and bumping products and can even be automated with the optional foam sensor.
vessel
reflux valve
vapor path
vapor path
2nd condenser
distillate cooler
Go to foam sensor
11 ©Büchi Labortechnik AG 2017
Setup: Glass configurationSpecial assemblies and receiving flasks
Glass assembly C (Reflux) Based on the reflux setup, the glass configuration C is equipped with a cold trap instead of a standard condenser. The cold trap can be filled with various cooling mixtures, such as dry-ice/acetone or others. Very low cooling is required if highly volatile solvents are to be collected.
Glass assembly VThe V assembly is a basic glass configuration only available for the Rotavapor® R-220 Pro Essential. Although similar to the reflux setup, the V assembly is not capable of reflux applications (no reflux tap). This assembly fulfills the same specifications as the equivalent of the lab-size Rotavapor®. The 3-way valve can be used as a feed or for aeration.
Receiving vessels All glass assemblies (expect V) are available with a single or dual receiver. The scaled flask has a volume of 10 liter. The receiving flasks can be drained without interrupting the distillation with the use of a shut-off tap. The dual receiver setup further allows for continuous distillations with one flask being drained while distillation takes place in the second flask.
Different boiling pointsDistillation of solvents of different boiling points is made easy with two receiving vessels. Solvent separation is possible without interrupting the distillation by simply collecting the distinct solvents in different flasks. Once the first solvent (lower boiling point) is distilled, close the tap and distill the second solvent with a lower vacuum in the second receiving flask. This prevents the first solvent from boiling in the receiving flask.
This glass configuration is therefore particularly suitable for reactions under reflux and/or solvents of a very low boiling point.
The V assembly is applicable for most distillations, however, not for foaming or bumping products, and only with one receiving flask.
cold trap
shut-off taps
Single receiver Dual receiver
feed valve
aeration valve
12 ©Büchi Labortechnik AG 2017
The distillation rate mainly depends on the available heating power of the system. The heating element of the Rotavapor® and the heat of vaporization of the product to be distilled together define the theoretical distillation rate. In practice, the theoretically determined distillation rate is unachievable as each setup has distinct system characteristics and ideal system parameters are often not feasible. First of all, it is important to understand the basics to evaluate the distillation rate, as well as the system limitations.
Heat of vaporizationEvery solvent has a unique heat of vaporization (also known as heat of evaporation or enthalpy of vaporization). The heat of vaporization is the energy required to transform a given quantity of a substance into a gas at a given pressure. In other words, the heat of vaporization is the energy needed to evaporate a substance. Please find a list of a wide range of solvents in the instruction manuals of all Rotavapors® and vacuum controllers or in relevant literature. The heat of vaporization is usually stated as ∆Hvap and is defined in J/g.
Different heating elementsConsidering that the distillation rate directly depends on the heating power, three heating elements of different capacities are available for the Rotavapor® R-220 Pro. The standard heating unit has a power output of 3600 W, there are more powerful units offering a 4200 W heater and a high perfomance unit at 6300 W. The chart to the right shows the maximum achievable distillation rate of acetone using each version of the Rotavapor®
R-220 Pro.
Important system parameters The maximum distillation rate is calculated assuming ideal conditions for a fast distillation. Several system parameters influence the distillation rate which should be considered. For the Rotavapor® R-220 Pro these are:
Water: ∆Hvap = 2261 J/g = 2261 Ws/gEnergy required to evaporate 1 kg of water:
Heating capacity R-220 Pro = 3600 WTheoretical distillation rate:
Effectiveness: 70% 4 kg/h
Max. distillation rate of water: 4 l/h
Calculation
2261 W · s · h · 1000 gg · 3600 s · kg
3600 W628 Wh
628 Wh
5.7 kg/h=
=
• Maximum rotation speed• Temperature difference between bath
and boiling point of about 40 °C• Cooling temperature at least 10 °C
(better 20 °C) below vapor temperature • Adequately high cooling flow (outlet
temperature about 5 °C below vapor temperature)
• Cooling medium: water• Strong vacuum source
Ideal setup
However, for various reasons the ideal system parameters may often not be realistic, such as:• maximum rotation is not possible (foaming or
bumping product)• unable to achieve the required temperature
difference (thermosensitive product)• the solvent to be distilled is usually not pure• oil is used as heating medium (lower heat
transfer properties than water)
3600 W
30
15
25
10
20
5
04200 W 6300 W
Dis
tilla
tion
rate
(L/h
)
Maximum distillation rate of acetone
Table of distillation rates
13 ©Büchi Labortechnik AG 2017
Efficiency: Increase the performance Distillation rate and influencing parameters
Temperature difference between bath and vapor (°C)
5
10
15
20
25
10 20 30 40Dis
tilla
tion
rate
of
acet
one
(L/h
)
Acetone distillation as a function of
Temperature
20 L, 130 rpm
10 L, 130 rpm
20 L, 30 rpm
Flask
Rotation
In order to achieve the maximum distillation rate at a specific heating power, it is important to consider the following critical system parameters; temperature difference, rotation speed and flask size as well as flask immersion.
Tsample ≈ Tvapor
∆Tbath - vapor = 35 - 40 °C
The higher the temperature difference between the sample in the flask and the bath, the better, in general, is the heat and energy transfer to the sample. Sample and vapor temperatures are approximately the same. Hence, adjusting the vacuum not only affects the boiling point but also the temperature in the flask.
Temperature difference
Best perfomance is reached at a temperature difference of 35 - 40 °C. With temperature differences above this value are difficult to achieve due to the limited heating capacity.
In general, the faster the rotation, the faster the distillation. This is due to the increase in surface of the liquid as well as the intensity of the agitation generated by the rotation.
Rotation speed
The flask size and thinkness as well as the immersion depth also influence the distillation rate. However, the flask properties account for the smallest share of the three principal factors.
Flask size & immersion
Tbath
Tsample
Tvapor
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Efficiency: Increase the performance Distillation rate and influencing parameters
Cooling may not have an equally strong effect on the distillation rate as the temperature difference and the rotation have. However, it is necessary to provide sufficient cooling to facilitate complete condensation. Poor cooling results in less condensation and in vapor escaping the system through the vacuum pump. Solvent emissions in the lab pose serious health and environmetal risks and should be avoided. Further, insufficient cooling may result in a reduced recovery rate.
ExamplesMaximum distillation rates of selected solvents
SolventMaximum
distillation rate in liter / hour
Ethyl acetat 25.5Heptane 35.4Hexane 37.2Isopropyl alcohol 16.53-Methyl-1-butan 18.8Methylethylketone 23.8Methanol 9.3Pentane 37.9n-Propylalcohol 14.31,1,2,2-Tetrachloroethane 231,1,1-Trichloroethylen 23.8Toluene 24.4Trichloroethylene 26.4Water 4Xylene 26.7
Crucial cooling parametersTwo parameters are important when it comes to cooling; the coolant flow rate and the temperature difference between coolant and vapor. It is vital to maintain sufficient coolant flow throughout the system. For the Rotavapor® R-220 Pro 120-150 L/h are required whereas 200-250 L/h are adequate for the Rotavapor® R-250. In terms of temperature difference between coolant and vapor, approximately 10 °C are sufficient.
SolventMaximum
distillation rate in liter / hour
Acetic acid 12.4Acetone 20.7Acetonitrile 13.6n-Pentanol 18.7Benzene 18.8n-Butanol 18Chloroform 23.1Cyclohexane 29.8Dichloromethane 18.3Diethylether 32.61,2-Dichloroethane 21.9Diisopropylether 39.3Dioxane 21.5Dimethylformamide 16.5Ethanol 13
Insufficient cooling:
condensation
vapor
Emissions
TvaporTcoolantsufficient flow rate
∆Tcoolant - vapor = 10 °C
15 ©Büchi Labortechnik AG 2017
Efficiency: Increase the perfomance Cooling influence
Further automation accessories:
The Rotavapor® R-220 Pro offers various levels of automation; built-in features of the standard R-220 Pro already allow for certain degree of automation while a fully automated system requires some additional accessories. The following modes are included in any Rotavapor® R-220 Pro model:
• Timer: Automatic switch into standby and rotation stop after a set time. Further, the heating is stopped and the heating bath is lowered.
• Method: Program and store different methods or SOPs.• App: Process supervision by smartphone or tablet. Push notifications if the distillation is complete or an error
occurs. Simply download the free app and connect to the Rotavapor® via the internet.
The automatic distillation sensor is the perfect add-on to your Rotavapor® R-220 Pro: Based on the current cooling and bath temperatures respectively, the ideal vacuum settings are determined and adjusted automatically. Furthermore, the sensor notices when the distillation is complete and stops the instrument.
Automatic distillation
This sensor detects the level of condensed solvent in the receiving flask and allows for concentration of a defined volume, e.g. from 10 L starting volume to 3 L. Simply position the level sensor at 7 L on the receiving flask. The sensor also acts as safety feature and prevents from overflowing.
Level sensor
Cooling water valve
Once the distillation is complete, the cooling water valve ensures the cooling water inflow is stopped and no additional water is wasted.
The foam sensor detects rising foam in the flask and helps to control foam formation. In order to disrupt developing foam, short aeration impulses are released. This allows for unattended distillation even of challenging samples.
Foam sensor
To applications
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Automation: Get more out of your system Minimize user interaction
OverpressureExcess pressure in the system automatically triggers the aeration valve resulting in immediate pressure release. At the same time, an error message appears informing the user.
Blocked rotationThe system automatically stop and prompts an error message if the rotation is blocked for 20 seconds or longer. In addition, the slow rotation start gives the user enough time to react should a problem arise (e.g. open clamp).
OvertemperatureThe unit automatically stops heating if the bath exceeds the set temperature by 15 °C. Further, the heating element has a mechanical temperature exceedance switch at 200 °C.
STOP
STOP
Additional safety add-ons:
The Rotavapor® R-220 Pro includes various safety aspects as standard features, such as plastic coated glass parts ("P+G" certificate) or the snap flange coupling for the evaporation flask. Depending on its use and environment, additional measures may be necessary to further protect the system.
OverflowThe bath overflow feature prevents from overspill if the bath content is filled too quickly. Once a certain level is reached, the bath starts to drain the content at the critical level.
The bath shield protects the operator from splashes and in case of a flask breakage. The evaporation flask is uncoated, therefore the bath shield is available for additional safety. The rotation stops if the shield is open.
Bath shield
User protection is guaranteed by P+G coating of the glass assembly. However, if the glass assembly itself should be protected from external influences, the safety shields are recommended.
Safety shields
Depending on the installation location, the Rotavapor® might be at risk of falling objects (e.g. walkway above). These special grids protect the flask and glass assembly in combination with the bath and safety shields.
Protection grids
17 ©Büchi Labortechnik AG 2017
Safety: Always well-protected Included and additional safety features
The Rotavapor® R-220 Pro is designed for easy and safe operation. For even further comfort, a range of additional accessories are availble.
Manual flask handlerThis multifunctional tool ensures safe and easy handling of hot and wet flasks. The handler is designed for a single person to safely mount, dismount and carry large flasks.
Flange adapterIn case a smaller amount of sample should be distilled and a lab-size Rotavapor® is not at hand, this handy flange adapter allow easy mounting of 1-3 L flasks on the Rotavapor® R-220 Pro.
Vacuum pump V-600This PTFE membrane vacuum pump runs quietly and smooth, allows speed controlled operation and guarantees a continuous and steady distillation process.
Recirculation chiller F-325 The strong 2500 W chiller allows for maximum flexibility by supporting the Rotavapor® as a sufficient cooling source as well as providing space for the vacuum pump including a secondary condenser. The compact combination is a convenient mobile distillation unit independent of a local vacuum or cooling source, secured by lockable wheels.
TrolleyThis trolley is specifically designed for the Rotavapor® R-220 Pro and allows either for fixed and safe installation (4 lockable wheels) or for mobile movement to different places. It further offers space for a vacuum pump.
Vacuum valveThis valve is required to controll vacuum sources other than the V-600.
Cooling temperature sensorKnowledge of the cooling temperature is one of the prerequisites to optimize the distillation process and ensure sufficient condensation. This sensor is not needed, if a chiller is used.
Vapor duct sinter plateDrying processes often produce fine dust. The vapor duct with sinter plate prevents the dust from entering the condenser and avoids product loss.
18 ©Büchi Labortechnik AG 2017
Comfort: Further accessories Make your life easier
In some applications, it is required to cool down the evaporating flask. The customer requesting a solution had so far added ice for cooling, however, this was neither precise nor practical. An inlet cooling coil is connected to the recirculating chiller allowing for exact bath temperature control, also below room temperature.
Inlet cooling coil
In addition to the coated glass parts, this customer asked for more metal protection of the glass parts. Special protection for all cylindrical glass parts was designed and custom made. The material used is a combination of a metal net and the BÜCHI plastic coating.
Additional protection
This customer expressed the desire to wash down the assembly by additional ports on the top of the Rotavapor®. Three large openings with caps were added to the glass part.
Additional glass ports
Dealing with light sensitive products is challenging. For the Rotavapor® R-220 Pro, a straighforward solution could be found. Amber coating is applied to the evaporating flask to protect the product. Branding of the coating guarantees equally good performance as the standard flask.
Amber glass flask
Contact us to discuss your requirements and ideas. We are always happy to help and develop ideal customer solutions tailored to your needs. In general, the following components can be modfied: • glass parts (type and number of connections,
dimensions or even new parts)• mechanical parts (depending on suppliers)• electronic and software modifications (time-
and test intensive)
Much more
Customization of various system components are easily possible. The following represents a small selection of customized parts, however, many more have been realized.
Several glass assemblies are available at reduced height, however, this customer requested an even shorter setup. BÜCHI glass assemblies are made in house. Hence, adaptations to special demands are easily possible. Further height reduction was achieved by redimensioning the glass assembly.
Modified glass assembly
19 ©Büchi Labortechnik AG 2017
Comfort: Customize to your needs We are happy to help
My product is...
However, many products require adjustments to achieve best results. The following section lists the most common challenges in concentration applications and according solutions given by experts.
The most common use of the industrial Rotavapor® is the concentration of products. As wide as the range of products to be processed by the Rotavapor®, as various are the methods to do so. Generally, the goal is to achieve a gentle concentration of the product in the shortest possible time. For regular and trouble-free samples (e.g. heat resistant, no tendency to foam or bump during distillation), the following settings are recommended: • bath temperature: 60 °C• vacuum: recommended pressure according to the solvent list (b.p. of 40 °C)• cooling: 20 °C or lower• rotation speed: maximum
...heat sensitive
bath: 40 °C
vacuum: solvent list or 10 °C < bath cooling: 10 °C < vapor
...aggressive
vacuum: reduced pressure cleaning: rinse and dry thoroughly
cooling: sufficient flow
...heat sensitive
Set the bath temperature to 40 °C (or other adequate temperature of the product).Adjust the vacuum to the recommended pressure according to the solvent list (b.p. of 30 °C) or 10 °C below bath temperature. Make sure the cooling is 15 °C (or at least 10 °C below vapor temperature)
Further recommended:Cooling water temperature sensor
...aggressive (acid)
Ensure the distillation is always under reduced pressure (vacuum) to prevent acid vapor passing the vacuum seal and entering the gear head (corrosion). Clean and dry the instrument entirely after such a distillation. Provide sufficient cooling to avoid emissions to the environment.
20 ©Büchi Labortechnik AG 2017
Applications: Concentration Recommendations for your application
My product...
...is viscous
Reduce rotation
...foams or bumps
rotation: 40 rpm
vacuum: according solvent list. Lower cautiously. aeration: quickly when foam rises
bath: > 60 °C vacuum: according solvent list or min. ∆Tbath - boiling point = 20 °C
...contains high boiling solvents(>100°C at ambient pressure)
...foams or bumps
Moderate rotation speed (about 40 rpm) is mostly beneficial. However, the product may also foam less at high rotation or the foam formation changes during the evaporation process. Trials are required. The most critical parameter is the vacuum. It is strongly recommended to slowly lower the vacuum in small increments.Aerate as soon as foam starts rising.
Further recommended:• foam sensor• descending glass assembly • use of methods on integrated
control unit I-300
...is viscous
Reduce rotation speed: the product should not stick on the flask as it does in a centrifuge.
Set the bath temperature above 60 °C (maybe oil as heating medium).Set the vacuum at the recommended pressure according to the “solvent list” (b.p. of 40 °C). Is this impossible (e.g. because the required pressure would be below 20 mbar), set the pressure higher but ensure a temperature difference between bath temperature and the boiling point of at least 20 °C.
Further recommended:• splash protection• glass assembly R or RB
...contains high boiling solvents (>100 °C at ambient pressure)
21 ©Büchi Labortechnik AG 2017
Applications: Concentration Recommendations for your application
Purification or solvent recycling Unlike in the concentration use, the main interest in purification applications lies in the solvent and not the product. Here, the goal is to purify or recycle a solvent with minimal loss. In general, the recommendations are equivalent to those given in the concentration section, however, the focus is somewhat different.
DryingAnother important application is drying of a product. The product to be dried in the flask may already be concentrated or can even be a slurry. The main goal is to dry the product with minimal loss in the shortest time possible. Generally, the recommendations are equivalent to those given in the concentration section, however, with a slightly different focus.
Other applicationsNumerous applications can be performed using an Industrial Rotavapor®. The tips given above help to optimize almost any application. Test your application on a lab-size Rotavapor® and scale it up.
Solvent recycling
Distillation rate: slow
Bath / vacuum: high temp / low vacuum Attention: azeotropic mixtures
Drying
Distillation rate: maximum
Attention: foaming and bumping products.
Cleaning: avoid sample carryover
Solvent recycling
Maximum solvent purity requires a "slow" distillation rate. The faster the distillation, the higher the risk of transferring impurities via vapor. In addition, foaming or bumping should be avoided - where possible. For high boiling solvents, an elevated bath temperature as well as a lower vacuum (i.e. higher pressure) is recommended. Be aware of azeotropic mixtures (separation impossible by distillation).
Further recommended:• descending glass assembly (D, DB, D2
or DB2)• use of methods on integrated control
unit I-300
Drying
For maximum efficiency, it is important to keep the distillation rate as high as possible. Further, be aware of thermo sensitive, foaming or bumping products. The bumping risk increases if the product turns into a slurry. In addition, bumps may carry some of the product to the condenser resulting not only in product loss but also in cleaning challenges.
Further recommended:• descending glass assembly (easy to
clean)• vapor duct with sinter plate
22 ©Büchi Labortechnik AG 2017
Applications: Purification & Drying Recommendations for your application
23 ©Büchi Labortechnik AG 2017
Appendix: Solvent list Important parameters
Solvent Formula Molar mass in g/
mol
Heat of vaporiza-tion in J/g
Boiling point at
1013mbar in °C
Density in g/cm3
Recommended vacuum for a
boiling point of 40°C in mbar
Acetic acid C2H4O2 60.0 695 118 1.049 44
Acetone CH3H6O 58.1 553 56 0.790 556
Acetonitrile C2H3N 41.1 853 82 0.780 208
n-amylalcohol, n-pentanol C5H12O 88.1 595 37 0.814 11
Benzene C6H6 78.1 548 80 0.877 236
n-butanol C4H10O 74.1 620 118 0.810 25
tert. butanol
(2-methyl-2-Propanol)
C4H10O 74.1 590 82 0.789 130
Chlorobenzene C6H5Cl 112.6 377 132 1.106 36
Chloroform CHCl3 119.4 264 62 1.483 474
Cyclohexane C6H12 84.0 389 81 0.779 235
Diethylether C4H10O 74.0 389 35 0.714 850
1,2-dichloroethane C2H4Cl2 99.0 335 84 1.235 210
1,2-dichloroethylene(cis) C2H2Cl2 97.0 322 60 1.284 479
1,2-dichloroethylene(trans) C2H2Cl2 97.0 314 48 1.257 751
DiisoPropyl ether C6H14O 102.0 318 68 0.724 375
Dioxane C4H8O2 88.1 406 101 1.034 107
Dimethyl-formamide (DMF) C3H7NO 73.1 73.1 153 0.949 11
Dimethylsulfoxide C2H6OS 78.1 678 189 1.104 4
Ethanol C2H6O 46.0 879 79 0.789 175
Ethylacetate C4H8O2 88.1 394 77 0.900 240
Heptane C7H16 100.2 373 98 0.684 120
Hexane C6H14 86.2 368 69 0.660 360
IsoPropylalcohol C3H8O 60.1 699 82 0.786 137
Isoamylalcohol
(3-methyl-1-butanol)
C5H12O 88.1 595 129 0.809 14
Methylethylketone C4H8O 72.1 473 80 0.805 243
Methanol CH4O 32.0 1227 65 0.791 337
Methylene chloride,
dichloromethane
CH2CI2 84.9 373 40 1.327 850
Pentane C5H12 72.1 381 36 06.26 850
n-Propylalcohol C3H8O 60.1 787 97 0.804 67
Pentachloroethane C2HCl5 202.3 201 162 1.680 13
Pyridine C5H5N 79.1 511 115 0.980 61
1,1,2,2-tetra-chloroethane C2H2Cl4 167.9 247 146 1.595 20
1,1,1-trichloroethane C2H3Cl3 133.4 251 74 1.339 300
Tetra-chloro-ethylene C2Cl4 165.8 234 121 1.623 53
THF
(tetrahydrofurane)
C4H8O 72.1 72.1 67 0.889 374
Toluene C7H8 92.2 427 111 0.867 77
Trichloroethylene C2HCl3 131.3 264 87 1.464 183
Water H2O 18.0 2261 100 1.000 72
Xylene (mixture)
o-xylene
m-xylene
p-xylene
C8H10
C8H10
C8H10
C8H10
106.2
106.2
106.2
106.2
389
144
139
138
0.880
0.864
0.861
25
24 ©Büchi Labortechnik AG 2017
Appendix: Solvent list Recommended vacuum for different boiling points:
Solvent Boiling point0 °C
Boiling point10 °C
Boiling point20 °C
Boiling point30 °C
Boiling point40 °C
Boiling point50 °C
Boiling point60 °C
Acetic acid 4 8 15 26 44 72 113
Acetone 91 150 239 370 556 815 Atmos.
Acetonitrile 29 50 83 134 208 315 465
n-amylalcohol, n-pentanol 1 1 3 6 11 19 33
Benzene 36 60 98 155 236 352 511
n-butanol 2 4 7 14 26 47 80
tert. butanol
(2-methyl-2-Propanol)
11 23 43 78 136 231 378
Chlorobenzene 4 7 13 22 36 56 86
Chloroform 77 126 199 306 457 665 947
Cyclohexane 40 66 107 166 252 372 536
Diethylether 242 382 585 871 Atmos Atmos Atmos
1,2-dichloroethane 30 51 83 132 203 304 444
1,2-dichloroethylene(cis) 77 127 204 317 479 705 Atmos
1,2-dichloroethylene(trans) 129 209 330 505 751 Atmos Atmos
DiisoPropyl ether 63 104 164 251 375 545 776
Dioxane 14 25 42 68 108 165 246
Dimethyl-formamide (DMF) 1 2 3 6 10 17 28
Dimethylsulfoxide 0 1 1 2 4 7 12
Ethanol 16 31 58 102 175 289 463
Ethylacetate 33 57 95 153 240 366 544
Heptane 16 28 47 77 120 183 273
Hexane 60 99 156 241 360 525 750
IsoPropylalcohol 11 23 43 78 136 231 378
Isoamylalcohol
(3-methyl-1-butanol)
1 2 4 9 16 29 49
Methylethylketone 38 64 103 160 243 359 518
Methanol 38 70 122 206 337 534 824
Methylene chloride,
dichloromethane
178 288 451 685 Atmos. Atmos. Atmos.
Pentane 245 377 563 819 Atmos. Atmos. Atmos.
n-Propylalcohol 5 10 20 37 67 115 193
Pentachloroethane 1 3 5 8 13 21 34
Pyridine 7 13 22 38 61 95 146
1,1,2,2-tetra-chloroethane 2 4 7 12 20 32 50
1,1,1-trichloroethane 49 81 129 200 301 442 634
Tetra-chloro-ethylene 6 12 20 33 53 83 126
THF
(tetrahydrofurane)
53 91 148 234 360 539 788
Toluene 10 17 29 48 76 118 177
Trichloroethylene 22 39 65 106 167 257 383
Water 6 13 23 42 72 120 194
Xylene (mixture) 3 5 9 15 25 40 63
(Atmos. = atmospheric pressure)
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