DE608360C - Process for the preparation of monohalogen substitution products of propane, butane and pentane - Google Patents

Description

GERMAN EMPIRE

ISSUED ON JANUARY 22, 1935

REICH PATENT OFFICE

PATENT LETTERING

M 608360 CLASS 12 ο GROUP 2oi

in the Hague, Holland

Butane and pentane

Patented in the German Empire on November 29, 1929

The invention relates to a process for the production of monohalogen substitution products of propane, butane and pentane and consists in first producing a gaseous mixture from the halogen and the hydrocarbon with the exclusion of light at the lowest possible temperature and this immediately without preheating and with the exclusion of light the reaction temperature is heated. This reaction temperature is advantageously from 360 to 380 ° in the chlorination of propane, 330-380 ° in the chlorination of butane and 250-330 ⁰ in the chlorination of pentane.

It has already been proposed to add paraffinic hydrocarbons in the gas phase halogenate. All of these methods suffer from the drawback that explosions are very easy and undesired side reactions occur which result in the formation of uniform reaction products complicate and often lead to the deposition of soot. To these disadvantages To avoid, in particular, the risk of explosion, it has already been proposed with considerable excesses of gaseous To work with hydrocarbons, which of course means that the capacity of the plant is not fully used and furthermore, not always uniform reaction products are obtained. It is also known per se that light affect the reaction between halogen and gaseous hydrocarbons can, and this known fact is also made use of, for example by providing artificial exposure by mercury lamps for chlorination of hydrocarbons used. Finally, it has already been proposed to mix pentane and chlorine with one another in the dark and then first preheat the mixture to about 100 °, whereupon it is then is heated to the reaction temperature. Here, too, there is a risk of explosion +5 present, because in this known method a system with a warning and display system must be used will. The reaction products obtained are also not uniform.

The new process differs advantageously from these known processes in that it enables the production of uniform monohalogen substitution products of propane, Butane and pentane without the risk of explosion, without having to deal with large excess

608860

Shots of hydrocarbons must be worked and without the use of artificial light sources to promote the reaction.
Examples

i. Pentane and chlorine are in a ratio of 3: ι separately to the reaction vessel supplied and heated to about 330 ^0th Carbonization takes place; when the chlorine content increases, increased symptoms of combustion occur.

However, if the pentane is evaporated in a chamber that is just heated enough that the pentane changes into vapor form, and this pentane is mixed with chlorine in the dark before the mixture enters the actual reaction chamber, in which the heating takes place, so carbonization and combustion cannot be detected, even if the amount of chlorine is increased. A reaction product is then obtained which contains less than ι o ° / ₀ dichlorides. All of the chlorine is consumed during the reaction.

2. A stream of chlorine and a stream of butane are separated at ordinary times Temperature fed to a mixing device which is designed so that light does not can kick. The mixture is then fed to a heated reaction chamber, which Access of light is also not permitted.

In this chamber 760 1 and 225 1 is chloro butane are heated to 330 ⁰ for 5 hours. 715 g of monochlorobutanes are then obtained, which consist mainly of the primary monochlorobutane and 53 g of dichlorobutanes. All chlorine is consumed in the reaction, which can be determined from the fact that free chlorine does not escape from the apparatus. 3. In the same way as in Example 2, a stream of chlorine and a stream of technical propane in a volume ratio of 1: 3, for example 10.6 liters of chlorine and 33.11 propane per hour, are mixed with one another in the cold and in the absence of light. This mixture is then passed through a 380 ⁰ heated reaction chamber. Since the monochlorides of propane ^{boil between 43 and 56 0} and are therefore extremely volatile, some pipes with activated carbon are connected behind the cooler in order to obtain non-condensed propyl chloride through the cooling device. After 6 hours, 107.4 g of condensate obtained by cooling are obtained, while a further 54.4 g of condensate are obtained from the activated carbon.

In the distillation of these products is 88 g monochlorides receives boiling 43-56 ⁰ next 21.5g dichlorides.

All of the chlorine is consumed by the reaction.

4. butane is mixed at 15 ⁰ in the dark with bromine in amounts such that a mixture of 3 moles of butane to 1 mole of bromine is produced. This mixture is passed through a glass tube heated in an electric furnace, which is completely protected against the ingress of light.

The reaction product emerging from the tube is condensed with dilute Washed alkali and water, dried over anhydrous sodium sulfate and fractionated.

a) A mixture of 28.5 l of butane with 31 g of bromine was passed through the tube in ^{3 1 1} _{2 hours.} The temperature of the pipe is 345 to 365 °. 16 g of a liquid with a strong tingling odor, which still contains butane and HBr, are collected in a receiver connected behind the pipe and cooled by ice water. After washing and drying it is fractionated; between 88 and 100 ° 10.6 g of a mixture of monobromobutanes pass over; Boiling point of the pure 1-Brombutans ioo °, of pure 2-Brombutans 90 to 93 ^0th If the residue is distilled further, HBr development and carbonization occur.

The bromine has been completely used up, the escaping vapors are colorless. "Theoretically 26.5 g of monobromobutane can be obtained from 31 g of bromine, so that the yield g | Xioo = 40%. .

b) A mixture of 31 g of bromine and 28 l of butane are passed through the tube. The temperature is kept at 250 to 255 ⁰ . The reaction product is collected under ice water. After completion, the receiver is fitted with a reflux condenser and shaken with the addition of lye. Most of the dissolved butane escapes. In the distillation, the washed and dried reaction liquid yields a good 18 g of monobromobutane fraction boiling between 84 and 10 °, while only ^1, ₂ g of higher-boiling bromides are found. So the yield of monobromobutane is no

- ¹ ^ _ X ioo = 70 ° / ₀ . All of the bromine has been used up.

c) The temperature of the tube is kept at 205 to 20 °. 29.5 l of butane with 31 g of bromine are sent through. In the distillation of the condensed in the ice-water reaction product are 21 g Monobrombutane, 8o ° / ₀ of the theoretical amount, the pass 85-102 ⁰ is obtained. The residue of higher bromine compounds is only 2 g.

Claims (2)

Patent claims:
ι. Process for the preparation of monohalogen substitution products of propane, butane and pentane by heating a mixture of hydrocarbon and halogen, in which the mixture of the gaseous starting materials is prepared in the absence of light at the lowest possible temperature, characterized in that the gas mixture is produced with the exclusion of light without Preheating heated to the reaction temperature. 2. Process for the preparation of alkyl monochlorides according to claim i, characterized in that the chlorination of propane between 360 and 380 ⁰ , of butane between 330 and 380 ° and of pentane between 250 and 330 ⁰ is carried out.