What is the Difference Between Buchner and Hirsch Funnel

The key difference between Buchner and Hirsch funnel is that Buchner funnel is used to collect a desired solid from a liquid by vacuum filtration method, whereas Hirsch funnel is a smaller Buchner funnel used to separate a solid from a small volume of liquid.

Buchner funnel and Hirsch funnel are important analytical instruments we use in laboratories in order to separate solids from liquids through the filtration technique. The Hirsch funnel differs from the Buchner funnel according to the size and design; the Hirsch funnel is smaller, and the walls of this funnel angle outward, whereas the walls of the Buchner funnel are vertical.

1. Overview and Key Difference
2. What is Buchner Funnel
3. What is Hirsch Funnel
4. Buchner vs Hirsch Funnel in Tabular Form
5. Summary – Buchner vs Hirsch Funnel

What is Buchner Funnel?

Buchner funnel is an analytical instrument used in the laboratory to filter liquids to separate a desired solid from the liquid. Traditionally, this equipment is made from porcelain. However, we can see glass and plastic funnels as well. In this Buchner funnel, there is a cylindrical part at the top, which is fitted with a fritted glass disc or a perforated plate.

We can use a funnel with fritted glass disc immediately. But if the funnel contains a perforated plate, the filtration material is a filter paper that is usually placed on the plate. There, we need to moisten the filter paper with the liquid in order to prevent any initial leakage. Thereafter, we can pour the analyte liquid into the funnel and let it draw through the perforated plate or the fritted glass disc through vacuum suction.

Using a Buchner funnel is very advantageous because it proceeds much more quickly rather than allowing the liquid to freely pass through the filter medium under gravity. Moreover, it is very important to measure the amount of liquid that we are going to use in this apparatus because it should not overflow the flask under the funnel.

Mostly, the Buchner funnel is useful in organic chemistry for the collection of recrystallized compounds. Vacuum suction can be useful for drying the wet recrystallized compound. However, it almost always needs a further drying step in an oven to reduce the residual liquid amount as much as possible.

The Buchner funnel is typically used along with the Buchner flask, Buchner ring, and sinter seals. During the process of filtration, it is important to have a vacuum-tight seal and stability of the Buchner flask and filter.

What is Hirsch Funnel?

Hirsch funnel is a type of Buchner funnel but with smaller dimensions and a different shape. Unlike the Buchner funnel, the Hirsch funnel contains walls that angle outwards, and the size of the funnel is comparatively small. Therefore, this funnel is important in separating solids from a small volume of liquid. Typically, this funnel can be used for essentially small quantities that range from 1 mL to 10 mL. Similar to the Buchner funnel, the Hirsch funnel also contains a perforated plate or a fritted glass. Furthermore, the Hirsch funnel is lightweight, easy to clean, and autoclavable.

What is the Difference Between Buchner and Hirsch Funnel?

Buchner funnel and Hirsch funnel are important analytical instruments we use in laboratories in order to separate solids from liquids through filtration techniques. The key difference between Buchner and Hirsch funnel is that the Buchner funnel is useful in collecting a desired solid from a liquid by vacuum filtration method, whereas the Hirsch funnel is a smaller Buchner funnel that we can use to separate a solid from a small volume of liquid.

The below infographic presents the differences between Buchner and Hirsch funnel in tabular form for side by side comparison.

Summary – Buchner vs Hirsch Funnel

The Hirsch funnel differs from the Buchner funnel according to the size and design; the Hirsch funnel is much smaller, and the walls of this funnel angle outward, whereas the walls of the Buchner funnel are vertical. Therefore, their uses are also different from each other. The key difference between Buchner and Hirsch funnel is that the Buchner funnel is useful in collecting a desired solid from a liquid by vacuum filtration method, whereas the Hirsch funnel is a smaller Buchner funnel that we can use to separate a solid from a small volume of liquid.