DE2048841A1 - Carbon tetrachloride and phosgene - from chlorine and compounds containing carbon, hydrogen and oxygen - Google Patents

Abstract

A mixture of CCl4 and COCl2 is prepared in the absence of catalyst by reacting Cl2 at 400-800 degrees C and 50-800 atmos. with either (a) cpds. contg. C,H, and O, where there is at least one more C-atom than O-atoms; or (b) a mixture of a (C,H, and O)-contg. cpd. CO, CO2, or H2O with an aromatic hydrocarbon, or a chlorinated aliphatic cycloaliphatic, or aromatic hydrocarbon. Cheap starting materials may be used, e.g. combustion gases.

Description

Process for the production of carbon tetrachloride and phosgene ( Addition to the German patent ... (patent application P 20 33 786.4) Subject of the main patent. .. (patent application P 20 33 786.4) is a process for the preparation of a mixture of carbon tetrachloride and phosgene through the reaction of oxygen-containing carbon-hydrogen compounds either alone or in a mixture with aromatic, chlorinated aromatic, chlorinated aliphatic or chlorinated cycloaliphatic hydrocarbons with chlorine in the absence of catalysts at temperatures between 400 ° and 800 ° C and pressures between 50 and 800 atm.

It has been shown that one can use a mixture of carbon tetrachloride and phosgene by the abovementioned process in the absence of catalysts, too then obtained if, instead of the oxygen-containing carbon-hydrogen compounds Carbon monoxide, carbon dioxide or water mixed with the aromatic, chlorinated aromatic, chlorinated aliphatic or chlorinated cycloaliphatic Uses hydrocarbons.

The invention now relates to a method for producing a Mixture of carbon tetrachloride and phosgene in the absence of catalysts according to patent ... (patent application P 2033786.4), which is characterized in that carbon monoxide, carbon dioxide or water mixed with aromatic, chlorinated aromatic, chlorinated aliphatic or chlorinated cycloaliphatic hydrocarbons with chlorine at temperatures between 4000 and 8000C and printing between 50 and 800 atmospheres react.

when working according to the process according to the invention, they are used oxygen-containing compounds, i.e. carbon monoxide, carbon dioxide or water practically quantitatively converted into phosgene, in such a way that always from one Oxygen atom creates a molecule of phosgene using a mixture of two or three of these compounds, the resulting amount of phosgene is additive from the Components to calculate. One can also determine from the (e.g., analytically determined) oxygen content of the added compounds directly calculate the expected amount of phosgene by one can expect practically 99 parts by weight of phosgene from 16 parts by weight of oxygen.

The formation of phosgene from carbon monoxide has been known for a long time. At the high temperatures of 400 - 8oo0C necessary for the formation of carbon tetrachloride, however, the equilibrium is according to the equation shifted strongly to the left. It is therefore surprising that in the presence of carbon tetrachloride the degree of conversion of the carbon monoxide is practically quantitative. The formation of phosgene from carbon dioxide and / or from water with the simultaneous formation of carbon tetrachloride has not yet been described.

The inventive method has the advantage that phosgene in addition to Carbon tetrachloride from such cheap components as carbon monoxide, carbon dioxide, Mixtures thereof and especially from water can be produced. For example, CO and Exhaust gases containing CO2, possibly also water from combustion processes may contain, use to produce phosgene in addition to carbon tetrachloride. Since the amount of phosgene is directly proportional to the amount of oxygen, it can easily by adding the desired amounts of carbon monoxide, carbon dioxide or water to the chlorination process can be controlled. This will make carbon tetrachloride manufacture variable and more economical.

The metering in of carbon monoxide and / or carbon dioxide and / or Water in the reactor can either be mixed with the hydrocarbons or in a mixture with chlorine. If you choose a separate metering of the oxygen-containing Components in the reactor, so is a pumping in liquid form in space Preferably near the pump-in points of the other components in order to avoid corrosion, It is recommended to pour it into liquid i? orm by pumping on the water after Reactor pressure has been brought to a preheater to heat up the water then enters the reactor as high-pressure steam.

Those other than carbon monoxide, carbon dioxide and water are still used Hydrocarbons are described in the main patent. All components can be in any Mixing ratios exist.

The execution of the reaction is the same as in the main patent.

Example 1 A vertical reaction tube is used for the etching used, d made of stainless steel for a nominal pressure of 1,600 atmospheric pressure from a nickel lining consists. It has a length of 3,300 mm, an outer diameter of 89 mm and a clear width of 40 mm. The reaction tube becomes divided into a pre-reaction zone and a main reaction zone. The lower electric jacket heater, which encloses the reaction tube over a length of 1,100 mm is increased to a maximum 250 ° C heated. The temperature is measured with an internal thermocouple. These Distance, which comprises 1.4 l, represents the pre-reaction zone. The upper electrical Jacket heating is set so that the internal temperature of the reactor is measured with a sliding thermocouple, is at 600 ° C. This route, the 2.7 1, represents the main reaction zone. The space-time yield is applied to this volume calculated. The reaction components chlorine and benzene are at room temperature on pumped into the lower end of the reactor in liquid form by means of a piston pump. That The reaction mixture is withdrawn from the top of the reactor and placed in a nickel-lined Cooler cooled to approx. 250 ° C. At the end of the cooler is located the expansion valve, with the help of which the desired pressure is maintained in the reactor will. The relaxed gases are first passed through a pressureless pre-separator, the is designed as an empty vessel with a capacity of approx. lo 1 without special cooling. Virtually all of the hexachlorobenzene and / or ilexachloroethane separates in this vessel away. The reaction gas is then cooled to approx. -75 C in a cooling coil, carbon tetrachloride, phosgene and chlorine condensing. The uncondensed one Hydrogen chloride is measured with a gas meter and checked for any entrainment Analyzed chlorine. Chlorine and hydrogen chloride were titrated in the condensate and phosgene determined by gas chromatography.

In the apparatus described above, at a pressure of 300 atü per hour: 500 g benzene with a water content of 0.05% (that's 0.25 g H2O) and 11 kg of chlorine with a water content of 32 ppm (that is o.35 g 1l20) are pumped in.

The excess of chlorine is above theory.

The following reaction products are obtained per hour: 5650 g of carbon tetrachloride (= 95.3% of theory) 3.3 g of phosgene (= 100% of theory) 75 g of liexachlorobenzene (= 4.1% of theory) 1370 g of hydrogen chloride (= 98% of theory). The yield data in this and the following Examples always relate to the theoretically calculable amount of the product based on the components used, benzene and water.

The space-time yield is 2090 g carbon tetrachloride per liter Reaction space per hour. The hexachlorobenzene will after distilling off the other reaction products and the excess chlorine in an approx. 50% strength Solution in carbon tetrachloride is pumped back into the reactor. Carbon tetrachloride, Phosgene and hydrogen chloride are separated from chlorine by distillation and the excess Chlorine in an amount of a. 4.2 kg per hour is circulated back into the reactor returned.

Example 2 In the same apparatus as in Example 1, at 230 ° C Pre-reactor temperature and 660 ° C main reactor temperature and a pressure of 240 atü per hour: Soo g benzene with a water content of o, o5% 200 g water, which after preheated to 23oC by pumping by a preheater and next to the benzene feed is metered in, and 12 kg of chlorine with a water content of 32 ppm is pumped in The excess of chlorine is 82% of theory, and the result is 3980 g of carbon tetrachloride per hour (= 94.5% of theory) iloo g of phosgene (= 99.5% of theory) 90 g of hexachlorobenzene (- 4.9% of theory) 2200 g of hydrogen chloride (= 99% of theory) The yield calculation of the carbon tetrachloride it is assumed that a stoichiometric part of the carbon atoms of benzene is required for phosgene formation.

The space-time yields for carbon tetrachloride are 1475 g / l # h and for phosgene 408 g / l # h.

After all of the reaction products have been separated off, the excess chlorine is removed pumped back into the reactor in the circuit.

Example 3 Under the same conditions as in Example 2 are used 800 g of monochlorobenzene 2Xo g of water and 12.5 kg of chlorine are pumped in per hour.

The excess of chlorine is 76% of theory.

The following is obtained per hour: 4700 g carbon tetrachloride (-97% of theory) 1080 g phosgene 9E 42 g ilexachlorobenzene (= 2.1% of theory) 2000 g of hydrogen chloride (= 95% of theory) Example 4 Under the same conditions as in Example 2, but at 550 ° C. main reactor temperature are pumped in per hour: 2000 g of a mixture that is so% hexachloroethane 30% trichlorethylene, 10% tetrachlorethylene, 200g water, at 230 ° C preheated, and 6 kg of chlorine (= 94% excess). Per hour: 1580 g of carbon tetrachloride are obtained (= 97.5% of theory) 1090 g of phosgene (= 99% of theory) 11 g of hexachloroethane (= 0.9% of theory) lo g hexachlorobenzene (- 1.0% of theory) 960 g of hydrogen chloride (= 98.5% of theory) example 5 In the same apparatus as in Example 1 are at 200 ° C prereactor temperature and 600 ° C main reactor temperature and a pressure of 240 atmospheres per hour 500 g of benzene with a water content of 0.05%.

800 g of liquid carbon dioxide from a pressure bottle (the dosing takes place in the immediate vicinity of the benzene feed) and 11 kg of chlorine (water content: 32 ppm).

The excess of chlorine is 65% of theory.

The following reaction products are obtained per hour: 4850 g of carbon tetrachloride (= 93.1% of theory) 900 g t of phosgene (= 100% of theory) 110 g of hexachlorobenzene (= 6.0% of theory) 1350 g of hydrogen chloride (= 96.5% of theory) The excess chlorine is in the circuit guided.

Example 6 In the same apparatus as in Example 1, at 100 ° C Pre-reactor temperature and 600 ° C main reactor temperature and a pressure of 100 atü per hour 500 g benzene (water content: 0.05%) 200 g carbon monoxide, the. by Cooling is condensed with liquid air and then liquid next to a piston pump the benzene feed was pumped in, and 11 kg of chlorine (water content: 32 ppm) were pumped in.

The excess of chlorine is 49%.

The following reaction products are obtained per hour: 5550 g of carbon tetrachloride (= 93.6% of theory) 700 g of phosgene (= 98.7% of theory) 120 g of hexachlorobenzene (= 6.6% of theory) 1360 g hydrogen chloride (= 97% of theory) There was no carbon monoxide in the exhaust gas found more. The excess chlorine was recycled.

The space-time yield is 2060 g carbon tetrachloride per liter and hour and 260 g of phosgene per liter and hour.

Example 7 The same apparatus as in Example 1 is used at 250.degree Prereactor temperature and 6000C main reactor temperature and a pressure of 80 atü a mixture of 300 g benzene (water content: 0.05%) 200 g monochlorobenzene per hour 100 g of o-dichlorobenzene and 12 kg of chlorine (water content: 32ppm) are pumped in.

The excess of chlorine is 54% of theory.

If after a period of about 3 hours the reactor is in the thermal Is equilibrium, one doses at the lower end, in addition to the chlorine feed In addition, a preheated combustion gas that has been compressed to 80 atmospheres is fed in an amount of 250 normal liters per hour, the 40 vol% carbon monoxide 50 vol% Contains carbon dioxide lo vol% water.

The following reaction products are obtained per hour: 4620 g of carbon tetrachloride (= 96% of theory) 161o g of phosgene (= 97% of theory) 56 g of hexachlorobenzene (= 2.8% of theory) approx. 1350 g hydrogen chloride (approx. 100% of theory) The excess chlorine is removed after separation of the reaction products in the cycle.

Example 8 In the same apparatus as in Example 1, at 250.degree Pre-reactor temperature and 660 ° C main reactor temperature and at a pressure of 80 atü per hour 1000 g of a heated to 160-170 ° C and thus brought to melt Mixture with the composition: 8% water 1% benzene o, 4% more chlorinated Benzenes 76% alpha-hexachlorocyclohexane 12% beta-hexachlorocyclohexane 1% gamma-hexachlorocyclohexane 0.8% delta-hexachlorocyclohexane, 0.8% epsilon-hexachlorocyclohexane and 6.5 kg of chlorine pumped in.

The excess of chlorine was 1o3% of theory.

The following reaction products are obtained per hour: 2520 g of carbon tetrachloride (= 95.2% of theory) 246 g of phosgene (= 56% of theory) 34 g of hexachlorobenzene (= 3.5% of theory) approx. 900 g of hydrogen chloride (approx. 100% of theory) The lower yield of phosgene is based very likely that the hexachlorocyclohexane isomer mixture on heating some dehydration of the product has taken place.

Claims (2)

Patent claims 1) Method of making a mixture of carbon tetrachloride and phosgene in the absence of catalysts according to patent .... (patent application P 2033 786.4), characterized in that carbon monoxide, carbon dioxide or water mixed with aromatic, chlorinated aromatic chlorinated aliphatic or chlorinated cycloaliphatic hydrocarbons with chlorine at temperatures between 4000 and 8000C and pressures between 50 and 800 atm. 2) Method according to claim l, characterized in that carbon monoxide, Carbon dioxide or water used in a mixture.