Pressure reactor

Key takeaways

Pressure reactor belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pressure reactor to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pressure reactor from memory before moving on to harder problems.

Reference excerpt

A pressure reactor, sometimes referred to as a pressure tube, or a sealed tube, is a chemical reaction vessel which can conduct a reaction under pressure. A pressure reactor is a special application of a pressure vessel. The pressure can be caused by the reaction itself or created by an external source, like hydrogen in catalytic transfer hydrogenation.

Advantages A pressure reactor can offer several advantages over the conventional round-bottom flask. Firstly, it can conduct a reaction above the boiling point of a solvent. Secondly, the pressure can reduce the reaction volume, including the liquid phase, and in turn increase concentration and collision frequency, and accelerate a reaction. Increase in temperature can speed up the desired reaction, but also speed up the decomposition of reagents and starting materials. However, pressure can speed up the desired reaction and only impacts decomposition when it involves the release of a gas or a reaction with a gas in the vessel. When the desired reaction is accelerated, competing reactions are minimized. Pressure generally enables faster reactions with cleaner reaction profiles. The above benefits from a pressure reactor has been shown in microwave chemistry. E.g., if a Suzuki Coupling takes 8 hours at 80°C, it only takes 8 minutes at 140°C in a microwave synthesizer. The microwave effect is a controversial topic. Later experiments show some of these early reports to be artifacts and rate enhancement is strictly due to thermal effects. If a pressure reactor is engineered properly, it can meet 4 out of 12 green chemistry principles

1, less solvent and cleaner reaction profile result in less waste 5, less solvent is needed 6, short reaction time can save up to 92 percent electricity and 200 gallons of cooling water per refluxed reaction 12, closed vessel can prevent releasing toxic gas and explosions.

Types of Pressure Reactors

Standard glass pressure reactor Glass Pressure reactors are typically used when an operator needs to observe how a reaction takes place. Although the pressure ratings on these systems are lower than most metal pressure reactors, they are still an efficient set up for reaching responsible pressure limits. The ratings on glass vessels are directly related to the diameter of the vessel. The larger the diameter, the lower the allowable pressure. Integrated bottom valves can also impact the pressure ratings. A bottom valve on a glass vessel typically relates to a lower allowable working pressure. These are all variables determined by the process and parameters of each individual reaction. Glass pressure vessels can also be used in inert applications. These vessels are used in reactions included but are not limited to Hydrogenations, Polymerizations, Synthesis, Catalytic, petrochemical, crystallization, and so on. One of the drawbacks of a standard glass pressure reactor is the potential explosions due to hard-to-predict excessive internal pressure and lack of relief mechanism. However, with proper safety implementation provided by the manufacturer, the operator can perform most reactions in a safe manner.

Fisher-Porter tube A Fisher-Porter tube or Fisher-Porter vessel is a glass pressure reactor used in the chemical laboratory. Manufactured by Andrews Glass Co. of Vineland NJ

Metal pressure reactor Metal Pressure reactors are typically used for high pressure reactions. They have a much higher pressure rating than glass reactors. Although they have a higher pressure rating, they still have their own distinct flaws. One of which would be that metal vessels are more susceptible to corrosion. The material of construction (MOC) is particularly important during the design phase of a metal pressure reactor. The correct MOC can reduce or even eliminate the corrosion seen in the vessel but, depending on the material chosen, could increase the price of a system. Metal vessels are also much heavier and should be handled carefully when performing maintenance. Metal high pressure reactors are used in reactions included but are not limited to Hydrogenation, Polymerization, Synthesis, Catalytic, Petrochemical and so on. They are also used to perform research such as Upstream, Biomass, Biopolymer, Zeolite, etc. The drawbacks of a metal pressure reactor (bomb) are set-up, maintenance, and corrosiveness.

Microwave synthesizer The drawbacks of a microwave synthesizer are solvent limitation

See also Pressure cooking Pressure vessel

References

Illustrations

Worked examples

Example 1 — a first encounter with Pressure reactor

Start with the simplest possible case. Write down what Pressure reactor claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pressure reactor before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pressure reactor ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pressure reactor

In research: Pressure reactor appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pressure reactor in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pressure reactor is common in secondary-school and first-year university syllabi. It links to neighbouring topics Laboratory equipment, Laboratory techniques, so understanding it makes those chapters shorter.
In everyday life: Look for Pressure reactor outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Pressure reactor in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pressure reactor means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pressure reactor out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pressure reactor in simple terms?

A pressure reactor, sometimes referred to as a pressure tube, or a sealed tube, is a chemical reaction vessel which can conduct a reaction under pressure. A pressure reactor is a special application of a pressure vessel.

Why does Pressure reactor matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pressure reactor?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pressure reactor.