A jacketed glass reactor is the workhorse at the center of a lot of process chemistry labs, and it's also one of the easier pieces of equipment to buy wrong. Order a reactor that's too small and you cap your batch size on day one. Order one that's too big for your heating and chilling setup and you'll wait hours for it to reach temperature. This jacketed glass reactor buying guide walks through the sizing, features, and supporting equipment that actually matter, so you can spec a system that fits your process instead of forcing your process to fit the reactor.
What a Jacketed Glass Reactor Actually Does
A jacketed glass reactor is a double-walled borosilicate vessel. Your reaction happens in the inner chamber, while a heat-transfer fluid circulates through the outer jacket to precisely control temperature. Because the walls are glass, you can watch the reaction the entire time — color changes, phase separation, crystallization, and mixing behavior are all visible, which is a real advantage over stainless steel vessels.
These reactors handle mixing, heating, cooling, and reactions under vacuum, all in one vessel. Common uses include crystallization, synthesis, extraction, distillation, and controlled cooling for winterization. The combination of visibility, temperature control, and vacuum capability is why they show up in everything from academic labs to full production suites.
Sizing: Match the Reactor to Your Batch
Reactor size is quoted by the working volume of the inner vessel, and the useful range spans from benchtop 1L and 2L units up to 100L and 200L floor-standing systems. The mistake most first-time buyers make is buying for the batch they hope to run someday instead of the batch they run today.
Small (1L–5L): R&D and Method Development
Benchtop reactors in the 1L to 5L range are ideal for developing a method, running small test batches, or teaching. They reach temperature quickly, use very little heat-transfer fluid, and fit on a standard bench. If you're proving out a process before committing to scale, start here — the fluid and energy savings alone make it worth having a small unit even after you scale up.
Mid-Size (10L–20L): The Workhorse Range
10L and 20L reactors are the most common purchase for working labs. They're large enough to produce meaningful output but still manageable for one or two operators, and they run on chillers and heaters that don't require enormous capacity. If you're not sure what to buy, a 20L reactor is the safe default for most process work.
Large (50L–200L): Production Scale
Once you're past 50L you're into production territory. These systems are floor-standing, need substantial heating and chilling capacity, and often require a hoist or lift to load and unload. Don't buy at this scale until you've validated your process on a smaller unit — the cost of a failed 100L batch is a lot higher than a failed 5L one. Browse the full range across our reactors collection to compare sizes side by side.
Single vs. Double Jacketed Reactors
You'll see two jacket configurations, and the difference matters more than the price gap suggests.
A single jacketed reactor has one outer jacket for the heat-transfer fluid. It's simpler and less expensive, and it's fine for processes that don't demand tight thermal insulation or extreme temperatures.
A double (triple-wall) jacketed reactor adds a vacuum insulation layer around the heating/cooling jacket. That insulation dramatically reduces heat loss to the room, which means you hold low temperatures more easily, waste less energy, and get far less condensation frosting up the outside of the vessel when you're running cold. If your process runs below 0 °C — winterization and crystallization are the classic cases — a double jacketed reactor is worth the premium. For ambient or high-temperature work, a single jacket is usually enough.
Temperature Range and the Equipment Behind It
A reactor's usable temperature range is defined not by the glass but by the circulator you pair with it. Borosilicate glass itself tolerates roughly -80 °C to +200 °C, but you'll only reach those extremes if your heat-transfer system can.
This is where a lot of reactor setups fall short. The reactor is only half the system — the other half is a chiller or heater (circulator) that pumps heat-transfer fluid through the jacket. To hit -40 °C in the vessel, your circulator needs to reach a colder setpoint than that, because there's always a temperature gradient across the jacket wall. As a rule of thumb, size your circulator to reach at least 10–20 °C beyond the vessel temperature you actually need, and make sure its cooling capacity in watts is rated at your target temperature, not just at room temperature where every chiller looks powerful.
Match your heat-transfer fluid to the range too: silicone oils cover a wide span, but for deep-cold work you may need a low-viscosity fluid that still flows at -40 °C or below. A fluid that turns to syrup at your target temperature will choke circulation and wreck your temperature control.
Vacuum Capability and Supporting Equipment
Most jacketed reactors are rated for full vacuum in the inner vessel, which lets you lower boiling points for distillation, degas solutions, and pull solvent off a mixture at gentle temperatures. To use that capability you'll need a vacuum pump matched to the vessel size, plus the right vacuum fittings and a cold trap to protect the pump from solvent vapor.
Think of the reactor as the center of a small system that usually includes: the reactor itself, a circulator for temperature control, a vacuum pump if you're running under vacuum, and often a rotary evaporator downstream for solvent recovery. Budgeting for the reactor alone and forgetting the supporting gear is the single most common planning mistake we see.
Features Worth Paying For
Beyond size and jacket type, a few features genuinely affect how the reactor performs day to day.
Overhead stirring. A quality PTFE stirrer with a variable-speed motor (a useful range is roughly 50–600 RPM) gives you consistent mixing across viscosities. Cheap stirrer motors bog down on thick slurries — don't skimp here.
Bottom discharge valve. A PTFE bottom-outlet valve lets you drain product cleanly without tipping or disassembling the vessel. It's a small feature that saves enormous hassle on every single batch.
Adequate ports. Look at the reactor lid: you'll want ports for the stirrer, a condenser or reflux setup, a thermometer or temperature probe, an addition funnel, and a vacuum line. Running out of ports mid-process is frustrating and hard to fix after purchase.
Explosion-proof / C1D1 rating. If you're working with flammable solvents in a classified area, you may need an explosion-proof motor and controls. Confirm your facility's requirements before ordering — retrofitting for compliance later is expensive.
Common Mistakes to Avoid
A few pitfalls come up again and again. Undersizing the circulator is the biggest one — the reactor reaches temperature painfully slowly, or never hits the low end you bought it for. Forgetting the supporting equipment is a close second; the reactor arrives and you realize you still need a chiller, a pump, and fittings before you can run anything. Buying too large too early wastes fluid and energy on every batch and makes small R&D runs impractical. And overlooking chemical compatibility — borosilicate and PTFE handle most solvents, but strong bases and hydrofluoric acid attack glass, so verify compatibility with your specific chemistry.
Which Reactor Is Right for You?
If you're developing methods or running small batches, start with a 1L–5L benchtop single jacketed reactor and a modestly sized circulator. If you're doing routine process work, a 10L or 20L double jacketed reactor paired with a properly sized chiller/heater is the reliable default. If you're scaling to production and have already validated your process, step up to 50L–200L — but budget for the heavy-duty chilling, heating, and handling equipment that scale demands.
Not sure how to match a reactor to your chiller, pump, and downstream equipment? That's exactly the kind of question our team answers every day. Browse our jacketed glass reactors, or request a quote and we'll spec a complete, correctly sized system for your process — reactor, circulator, vacuum, and all the fittings in between. If you're planning a full lab build, ask about our consulting services and we'll help you get the whole setup right the first time.