The main difference between a single-layer and a double-layer jacketed glass reactor is the presence of an additional jacket around the inner vessel in the double-layer design.
A single-layer jacketed glass reactor has a single jacket around the inner vessel, which is used to circulate heating or cooling fluids to control the temperature of the reaction. The jacket is typically made of stainless steel, and the inner vessel is made of glass. This design is simple and easy to use, but it may not provide sufficient insulation for some reactions, particularly those that require precise temperature control or long reaction times.
A double-layer jacketed glass reactor has an additional jacket around the inner vessel, which provides additional insulation and allows for greater temperature control during the reaction. The space between the two jackets is filled with an insulating material, which reduces heat loss and improves temperature control. The outer jacket is typically made of stainless steel, and the inner jacket and vessel are made of glass. This design is more complex and requires additional equipment to circulate fluids through both jackets, but it provides better temperature control and insulation for more demanding reactions.

Differences between single-layer and double-layer jacketed glass reactors:
- Temperature control: Double-layer jacketed glass reactors provide better temperature control than single-layer reactors, due to the additional insulation provided by the outer jacket. The double-layer design allows for precise regulation of the temperature of the reaction, which is important for many types of chemical reactions.
- Insulation: The double-layer design provides better insulation than single-layer reactors, which is important for reactions that require long reaction times or precise temperature control. The space between the two jackets is filled with an insulating material, which reduces heat loss and improves temperature control.
- Heat transfer: Double-layer jacketed glass reactors may have slower heat transfer than single-layer reactors, due to the additional insulation provided by the outer jacket. This may be a disadvantage for reactions that require rapid heating or cooling.
- Complexity: Double-layer jacketed glass reactors are more complex than single-layer reactors, due to the additional equipment required to circulate fluids through both jackets. This may make them more difficult to use and maintain, and may require additional training for laboratory personnel.
- Cost: Double-layer jacketed glass reactors are typically more expensive than single-layer reactors, due to the additional equipment and materials required for the double-layer design. However, the improved temperature control and insulation may make them a better choice for certain reactions that require precise temperature regulation.
In summary, double-layer jacketed glass reactors provide better temperature control and insulation than single-layer reactors, but may be more complex and expensive. The choice of reactor design depends on the specific requirements of the reaction and the level of temperature control and insulation needed.