Kipp generators

Manufacture. Small cylinders of hydrogen sulfide are readily available for laboratory purposes, but the gas can also be easily synthesized by action of dilute sulfuric or hydrochloric acid on iron sulfide, calcium sulfide [20548-54-3], zinc sulfide [1314-98-3], or sodium hydrosulfide [16721 -80-5]. The reaction usually is mn in a Kipp generator, which regulates the addition of the acid to maintain a steady hydrogen sulfide pressure. Small laboratory quantities of hydrogen sulfide can be easily formed by heating at 280—320°C a mixture of sulfur and a hydrogen-rich, nonvolatile aUphatic substance, eg, paraffin. Gas evolution proceeds more smoothly if asbestos or diatomaceous earth is also present. 

Take the 250-mi volumetric flask contg material extracted by carbon tetrachloride as shown here under H- Analytical Procedures, step 1, and transfer from it 25 ml (using a calibrated pipet, previously rinsed with CC14 and dried, to the titration flask F, Evaporate the CC14 to dryness with a slow stream of air and then sweep the air off with a stream of C02 from a cylinder (or from a Kipp generator). While continuing to pass C02 thru the flask, introduce... 

The hydrogen chloride may be generated after the methods used in Org. Syn. 2, 30, and 8, 113-114, or in a Kipp generator from fused ammonium chloride and concentrated sulfuric acid. 

It consists of a storage bottle, A, of 0.1 N titanium chloride titrant maintained under hydrogen produced by a Kipp generator an Erlenmeyer flask, B, equipped with a source of C02 or N2 to maintain an inert atmosphere in which the reaction takes place a stirrer and the buret, C. 

Titanium Chloride Solution (0.1 N) Transfer 73 mL of commercially prepared 20% TiCl3 solution into a storage bottle, and carefully add 82 mL of concentrated HC1 per L of final solution. Mix well, and bubble C02 or N2 through the solution for 1 h. Before standardizing, maintain the solution under a hydrogen atmosphere for at least 16 h using a Kipp generator. 

It is important that the gases (H2S and HCI) be passed very rapidly through the solution. Hydrogen sulfide from a pressurized cylinder can be used instead of a Kipp generator, enabling the gas to be passed at a very rapid rate. However, in this case, it is advisable to use a three-necked, round-bottomed flask fitted with two drying tubes to serve as pressure releases, since there is a pressure buildup as the temperature of the solution rises. 

FIG. 6-. The Kipp generator —a convenient apparatus for preparing hydrogen and other gases. 

In a 2-1. Kipp generator, 69 g. (1 mol) of sodium nitrite in stick form is treated with 2 M sulfuric acid. Thereby, a readily controlled flow of nitrogen(II) oxide is produced. 

The most widespread apparatus is still the Kipp generator. For production of air-free gas, e.g., COg for driving gases into nitrometers, it can be provided with an attachment that keeps the upper chamber completely filled with the gas and prevents the penetration of air into the decomposition acid. The operation of this apparatus is shown in Fig. 56. Honisch s variant of the Kipp generator, which assures complete utilization of the acid and prevents mixing of the used with the fresh acid, is increasingly popular, although the somewhat complex stopcock construction is sometimes troublesome. 

A Kipp generator can also beusedfor oxygen production. In this case, 3% H3O3 is used and the generator is charged with cubes made of MnOg and a binder. 

A layer of NaN03 is covered with two to three times its weight of water, and dilute sulfuric acid is added dropwise. Rod-shaped solid nitrite can also be decomposed with dilute sulfuric acid in a Kipp generator. Caution is recommended because the riser of the generator is easily plugged ty the precipitated Na3S04. The liberated gas is washed with 4N KOH it is quite pure. It may be purified further as above. 

A small Kipp generator may also be used for the reaction. 

Indeed, the old Kipp generators still found in out-of-the-way corners of most chemistry departments were designed expressly for the purpose of safely generating H2S in this way. If you have never seen a Kipp generator, ask around your department and see if anyone knows where you could find one. 

A convenient laboratory method for the preparation of SO2 in a Kipp generator has used the decomposition with dilute H2SO4 of cubes made of three parts calcium sulfite and one part calcium sulfate. 

The standard lab preparation is to gently heat ferrous sulfide (FeS) with a strong acid in a Kipp generator. 

---