JPS5922689B2 - Process for producing chlorinated derivatives of ethylene - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing chlorinated derivatives of ethylene.

The field related to this invention relates generally to the preparation of chlorinated derivatives of ethylene, such as vinyl chloride and vinylidene chloride, and particularly vinyl chloride.

It is also closely related to methods for synthesizing chlorinated solvents from ethylene, chlorine and/or chlorhydrogen. Such solvents include highly chlorinated ethylenes such as perchlorethylene, and ethylene and/or partially chlorinated ethane are combined with hydrogen chloride and oxygen in one or more catalytic oxyhydrochlorides. Manufactured using a manufacturing method that involves a lining process. This manufacturing method is covered by British patent 9.
No. 62872. Vinyl chloride is produced from ethylene, elemental chlorine, and/or hydrogen chloride by various processes, but in most processes ethylene dichloride is pyrolyzed under pressure in the vapor phase to produce vinyl chloride and by-products. A cracking process is used to convert hydrogen chloride into hydrogen chloride.

This by-product hydrogen chloride is recovered in an oxyhydrochlorination step where it is reacted with added ethylene and oxygen to form dichloroethane, which is then sent to the cracking step. Recirculated. Many manufacturing processes also employ a direct chlorination process, in which ethylene and elemental chlorine are reacted in the liquid phase to produce methane dichloride, which is then decomposed to produce vinyl chloride. do. The direct chlorination, oxyhydrochlorination and/or cracking steps in all of these known solvent and monomer preparations have a selectivity of 1 to the desired chlorinated hydrocarbon end product.
00%: As a result, significant amounts of undesirable chlorine-containing by-products are produced in complex compounds ranging in composition from chloroform or ethyl chloride to trichloroethane and trichloroethylene, tetrachloroethane, hexachloroethane, hexachlorobutadiene, etc. Obtained as mixtures as well as aromatic compounds.

Clearly, these undesirable chlorine-containing by-products pose economic as well as socio-ecological treatment problems. A known and useful process for producing vinyl chloride involves a so-called "adiabatic" or six-step" reaction in which mixed vapors of ethylene and elemental chlorine are reacted at superatmospheric pressure and high temperature.

In such a process, ethylene and chlorine would react to form ethylene dichloride, which would decompose simultaneously thermally and catalytically to vinyl chloride and hydrogen chloride byproducts. The term "adiabatic process" derives from the two-step nature described above.
That is, the reaction between ethylene and chlorine is exothermic in nature, and the decomposition of its products is endothermic in nature. It is therefore theoretically possible to balance the heat generation and heat consumption of the two reactions and to operate almost adiabatically, supplying a reduced amount of heat by stiffness. Hydrogen chloride generated by such an adiabatic process is recovered in an oxyhydrochlorination step in which a mixture of by-product hydrogen chloride, ethylene and oxygen reacts catalytically to form ethylene dichloride; This is then recycled to the first stage adiabatic reactor. This type of method is shown in US Pat. No. 3,291,846. One undesirable feature of the known type of adiabatic vinyl chloride process is the relatively high proportion of polychlorinated by-products formed in the first stage chlorinator/cracking process, which means that ethylene, chlorine and/or a loss of raw materials such as hydrogen chloride, as well as a significant loss of thermal energy in a process presumably intended for adiabatic operation. Unfortunately, in some cases, such chlorine-containing by-products amount to as much as about 10-20 mole percent based on the starting material. Therefore, without providing a means to accommodate such large losses of raw materials and thermal energy in undesirable by-products, other attractive methods become economically unattractive. It turns out. Furthermore, conventional methods for producing dichloroethane as a precursor for both the monomer and the solvent mostly involve combining ethylene and elemental chlorine in the liquid phase using ethylene dichloride as a solvent at low temperatures. requires direct interaction.

Such reactions are highly exothermic, but unfortunately the heat generation occurs at such low temperatures that the only practical way to control the temperature is through the use of large amounts of process cooling water. be involved in Therefore, the heat of reaction can only be released into large water cooling towers or by disposing of the heated water into natural waterways. None of these heat treatment methods are satisfactory from socio-ecological and economic points of view. Therefore, a process for producing chlorinated derivatives of ethylene and chlorinated solvents from ethylene, chlorine and/or hydrogen chloride, in which the thermal energy produced is utilized within the overall process and the undesirable chlorinated hydrocarbon by-products are removed. It would be most desirable and advantageous to have a process in which the production of is substantially eliminated or the final result is not critical due to recycling of waste products during the process.

We recover the undesirable chlorinated hydrocarbon byproduct for reuse in the form of hydrogen chloride essentially free of elemental chlorine and chlorinated hydrocarbon impurities and introduce the hydrogen chloride into the process. It has been unexpectedly discovered that the above problems of conventional methods can be overcome or substantially eliminated by providing a method of recycling.

Furthermore, in the process for producing chlorinated hydrocarbons from ethylene, the specific thermal energy value of the crude by-product is returned to the process for preheating the raw and intermediate feeds. Specifically, the present inventors have developed a new and novel process for producing vinyl chloride, which is primarily based on ethylene and elemental chlorine as raw materials, but also allows easy use of hydrogen chloride. The steps of this process include (1) the adiabatic one-step reaction of ethylene and elemental chlorine at elevated temperature to form vinyl chloride and hydrogen chloride; (2) step (1) and also step (3) below. an oxyhydrochlorination step in which hydrogen chloride from is reacted with ethylene in the presence of oxygen over a Deacon catalyst to produce dichloroethane which can be recycled to step (1); and (3) a desirably containing chlorinated hydrocarbon by-product. low-temperature (approximately 400°C to 500°C) fixed bed or fluidized bed catalytic combustion process, in which the combustion gas stream is recycled to the oxyhydrochlorination step (2) to recover its hydrogen chloride content as dichloroethane and /or (2) raw material supply stream is the process (
3) is used to absorb the heat of combustion and return the thermal energy to vinyl chloride synthesis. The treatment of thermal energy in step (3) can actually be considered a fourth step, ie a closed thermal loop (ClOsedheat-100p). As used in this specification, the terms "chlorinated ethylene derivatives" and "chlorinated ethylene synthesis process" refer to the synthesis of vinyl chloride, vinylidene chloride, and Various methods of producing chlorethylene or chloroethane type compounds such as ethyl, 1,1-dichloroethane, 1,2-dichloroethane, trichloroethanes, trichlorethylenes, tetrachloroethanes, perchlorethylene, etc. and their Chlorinated ethylene synthesis is a general term encompassing products.Thus, chlorinated ethylene synthesis involves the direct chlorination of ethylene or chlorinated ethylene derivatives, converting the ethylene or its chlorinated derivatives into products with higher chlorine content; Oxyhydrochlorination of ethylene or chlorinated ethylene derivatives and any process of decomposition (dehydrochlorination) or rearrangement of chlorinated ethylene derivatives to produce chlorinated ethylene derivatives with even lower chlorine content. In general, the process of the present invention combines a method for the synthesis of chlorinated ethylene derivatives including at least one step of oxyhydrochlorination, and then converts the chlorine-containing intermediate and the desired chlorinated ethylene product. It consists of separating the unwanted by-products from the waste and subsequently subjecting the separated unwanted by-products to exothermic catalytic combustion.

The essential part of the invention is this combustion step. The catalytic combustion is accomplished by contacting the by-products with air and/or oxygen at atmospheric or superatmospheric pressure in a fixed or fluidized bed of solid alumina-containing twisted catalyst;
A temperature range of 00'C to about 500C is maintained, thereby producing a combustion gas stream consisting essentially of hydrogen chloride, carbon oxides, water and inert gases.

These combustion gases are recycled to the oxyhydrochlorination process or reaction system, but are required to be free of elemental chlorine or chlorinated hydrocarbon materials. This is because it creates unnecessary high boiling polychlorinated by-products in the gases exiting the oxyhydrochlorination step or reactor, further complicating the process. Furthermore, elemental chlorine at these temperatures is highly corrosive to all conventional metals and alloys. Elemental chlorine in these combustion gases therefore greatly increases the cost of (replacement of) equipment, thereby rendering the process impractical. Therefore, if the temperature of the catalyst bed is below 400°C, incomplete combustion will produce a gas stream containing hydrogen chloride mixed with unreacted and/or partially burned chlorinated hydrocarbon material. , the temperature of the catalyst bed is an important factor. When the temperature of the catalyst bed is above 500° C., elemental chlorine is produced by oxidation of hydrogen chloride.
Under the above conditions, a fluidized bed of solid alumina-containing twisted catalyst can be used to essentially completely oxidize most complex and discolored high boiling bottoms byproduct streams to produce hydrogen chloride.

Many of the bottoms produced during the purification of chlorinated solvents, ethylene dichloride, and vinyl chloride monomers are
They tend to contain benzene and/or more complex aromatics and are highly contaminated with iron chloride, tarry substances, and dispersed or suspended carbon. However, even the most viscous and tarry residues can be heated to reduce their viscosity and then injected under pressure into a twisted catalyst bed containing solid alumina without disrupting the operation of the catalyst bed. The pressure employed in the fixed bed or fluidized bed of the solid alumina-containing twisted catalyst is not critical as atmospheric or superatmospheric pressures can be employed.
However, since oxyhydrochlorination reactions are typically operated at pressures higher than atmospheric pressure, it is common to feed the combustion gas to the reaction system at the same or equivalent pressure.
Therefore, it is desirable to maintain the gas in the combustion bed at a pressure in the range of about 25 to 150 psig, preferably about 40 to about 100 psig. In all cases, the pressure should be maintained slightly higher than that during the oxyhydrochlorination step to avoid the need to pressurize the combustion gases. The alumina combustion catalyst used in the present invention has a high surface area, i.e. at least 10 square meters per gram (M
2/9 m). The most active alumina catalyst of this type is about 80 to about 400m7f1
It has been found to have a surface area in the range of m. The most useful alumina combustion catalyst used in this invention is the diameter 30
Contains pores with an average size in the range of ~60λ and about 100
The catalyst has a surface area in the range of ~200m79m. The alumina combustion catalyst of the present invention can be used in any wide range of particle size distributions required for good flowability, i.e., small amounts of particles, if any, with an average diameter of less than 20 microns or greater than about 200 microns; Particle size distributions with the largest portion having particles ranging from about 40 to about 140 microns in average diameter are readily available. Very small particles, or fines, with an average diameter less than about 20 microns will flow out of the reactor very easily and should be avoided. Similarly, large particles having an average diameter greater than about 200 microns are difficult to fluidize and should be avoided. It is clear from the nature of the process of the invention that the catalyst material should be non-friable and maximally resistant to attrition. In the fluidized bed combustion catalyst system of the present invention, the amount and flow rate of oxygen is sufficient to completely fluidize the catalyst bed as well as to provide sufficient oxygen to controllably combust the hydrocarbons in the waste or byproduct stream. It is necessary to use air.

In order to completely burn out the waste stream, it is necessary to feed at least 2 moles of oxygen to the reaction system per 1 mole of carbon C in the waste stream. However, in order to provide a suitable amount of oxygen to the fluidized catalyst bed, from about 2.5 to about 10.0 moles of oxygen per mole of carbon in the waste stream (0VC,) or (
Provide sufficient air to the bed to provide Q/0. Employing air feed rates that provide more than about 10.0 moles of oxygen per mole of carbon in the waste stream will result in loss of capacity and loss of catalyst and, more importantly, will result in hydrogen chloride being oxidized. There is an increased risk of formation of elemental chlorine, which must be avoided. Approximately 2 per mole of carbon in the waste stream
Employing air feed rates to provide less than molar oxygen results in only about 80-85% complete combustion. Preferred air supply rates are such as to provide about 2.5 to 5.5 moles of oxygen per mole of carbon in the waste stream. In the alumina combustion catalyst bed, the contact time between the bed and the waste is about 10 to about 50 seconds.

The catalyst, at its operating temperature, limits the combustion to essentially complete combustion of the chlorinated hydrocarbons in the waste stream, but leaves behind hydrogen atoms that are bonded to the chlorine atoms of the hydrogen chloride. This makes it possible to produce a gas stream that is practically free of elemental chlorine. Elemental chlorine is undesirable and its formation should be avoided as much as possible. The presence of chlorinated hydrocarbons in the combustion gases also increases the formation of by-products in the oxyhydrochlorination process, so combustion as complete as possible is important. After the waste is introduced into the alumina combustion catalyst bed, it is vaporized and then cleanly combusted in the controlled manner described above.

Direct injection of a liquid waste stream, which is often viscous and tarry and contains substances consisting of suspended carbon, does not degrade the catalyst bed and, in the case of fluidized beds, does not impair its fluidity. . Feeding the catalyst bed with waste or waste streams can be easily accomplished using standard equipment such as gear pumps, mechanical displacement pumps, etc. From the point of view of the temperature employed,
There are many known materials for containing catalyst beds that can withstand the corrosive environments encountered. However, in the process of the invention, the effects of corrosion in the catalytic combustion chamber or reactor are very gradual. From this point of view, a conventional heat exchange coil of conventional materials and design is inserted into the catalyst bed, where it is used as a coil for steam generation or for preheating of raw materials or intermediate materials of the process for the production of chlorinated derivatives of ethylene. It is used as one of the coils for Even when producing chlorinated derivatives of ethylene, where only about 3-8% of the initial ethylene feed is converted to by-products, the annual savings in thermal energy are considerable. Also, since the combustion process is operated at low temperatures, the resulting combustion gases can be fed directly to the oxychlorination reaction system without intermediate cooling. It has been found that most metal chlorides and metal oxides, when used alone, have some catalytic effect in the combustion process, but the effect varies in degree.

The difficulty with most of these compounds when used alone is that they act as deacon catalysts and convert or redistribute at least a portion of the chlorine content of the waste into new polychlorinated hydrocarbons. (Some of these are more resistant to oxidation).
When the metal catalyst is used as described above, the combustion gases generally contain significant amounts of polychlorinated unsaturated by-products. On the one hand, alumina (Al2O3) used in the present invention
The inventors have determined that the catalyst has the desired catalytic activity and that the combustion gases thereby produced contain very little and, under optimal conditions, essentially no elemental chlorine and chlorinated hydrocarbon materials. I found something unexpected. Additionally, the alumina catalysts of the present invention are inexpensive and have superior resistance to attrition and contamination of the waste byproduct feed stream with unburned carbon and trace amounts of metal components. The by-product streams separated in the various fractionation steps of many chlorinated ethylene synthesis processes contain up to 1-2% by weight of iron chloride as an impurity. In the alumina combustion catalyst bed of the present invention, iron chloride and the like are oxidized to particulate iron oxide, which is carried out of the catalyst bed by the combustion gas and collected in a cyclone separator. However, if the iron oxide is extremely fine, it passes through a cyclone separator and an oxyhydrochlorination reactor and is captured in a water scraper following the reactor. The small amount of iron oxide remaining in the catalyst bed has no apparent deleterious effect on catalyst bed efficiency. Also, the small amount of iron oxide carried by the combustion gases from the combustion reactor to the subsequent oxyhydrochlorination step usually does not affect the oxyhydrochlorination catalyst supported on alumina. The only negative effect of using combustion gas in the oxyhydrochlorination process is the significant increase in capacity due to the increased charge of inert gas from the combustion gas in the oxyhydrochlorination process feed. This is a slight decrease. In the process for producing chlorinated ethylene, in order to consume the by-product hydrogen chloride produced in the decomposition or rearrangement step, and as in the present invention, the hydrogen chloride component of the by-product combustion gas is used as a useful intermediate or final product. It is essential to have a hydroxychlorination step in order to convert it into a product.

A suitable oxyhydrochlorination reaction or process for producing ethylene dichloride or EDC includes ethylene,
A low humidity mixture of oxygen and hydrogen chloride is passed through a fluidized Deacon catalyst bed at superatmospheric pressure and at a rate that fluidizes the catalyst. The catalyst used is copper chloride supported on an alumina support. On the other hand, the entire amount of the catalyst used in the fluidized bed catalytic combustion process is alumina. The concentration of the copper chloride on the alumina support is typically about 3 to 3 as copper.
12% by weight and preferably about 3.5-7% by weight as copper. Steam generating coils placed within and in direct contact with the fluidized bed remove the heat of the exothermic reaction, thereby bringing the temperature in the bed from about 19°C to about 250°C and preferably about The temperature is maintained in the range of 220°C to about 240°C. When temperatures in the above ranges and pressures of about 10 to about 50 psig are balanced above the dew points of the reactants, products, and inerts, the fluidized bed reaction is essentially isothermal. With regard to dew point, it is essential that fluidized bed oxyhydrochlorination reactors receiving recycled combustion gases be operated at pressures and temperatures above the dew point of the gas in the bed.

The combustion gas contains water produced from the combustion of the hydrogen component of the feed by-product. Typically, fluidized beds of deacon-type oxyhydrochlorination catalysts are operated with an inlet gas mixture that is as low as practical in moisture to prevent condensation of moisture and/or other liquids in the bed. Must be. Such condensation elutes the active copper catalyst components and locally (HOt
-SpOt) tends to form localized areas of high concentration resulting in the formation of -SpOt). Water is also a by-product of the oxyhydrochlorination reaction and, if care is not taken, the total moisture content of the gases, including the recycle gas mixed together, can become too high. This is particularly the case in the upper part of the fluidized bed of commercial large scale fluidized bed oxyhydrochlorination reactors. Another important feature of the invention is that the thermal energy generated during the combustion of chlorine-containing by-products in the fluidized bed catalytic combustion process is utilized in other steps of the process.

The fluidized bed catalytic combustion reactor has a low combustion temperature, i.e. about 40
The oxyhydrochlorination process operates at temperatures ranging from 0°C to 500°C, whereas the fluidized bed temperature of the oxyhydrochlorination process is approximately 190°C.
It is operated at temperatures ranging from ~250<0>C. The temperature difference between the recycled combustion gas and the oxyhydrochlorination step is not very large. When the heat content of the combustion gas is mixed with the feed stream to the oxyhydrochlorination reaction system, the need for external heating for preheating is significantly reduced and often eliminated. Furthermore, because heat must be removed from the combustion bed to control the combustion temperature within a specified range, a substantial portion of the heat generated in the fluidized bed catalytic combustion process of the byproducts is transferred to the incoming feedstock. Alternatively, one or more intermediate feed streams can be recovered by subjecting them to heat exchange associated with a fluidized bed catalyst of a combustion reactor and returned to the process. Although more conventional steam generating coils placed in fluidized bed combustion reactors can be used for heat removal,
It has been found further desirable to recover the heat of combustion by passing the reactant feed through coils and/or other heat exchangers in contact with the catalyst of the combustion bed. In conjunction with the preferred process of the present invention, the adiabatic reaction for converting ethylene/chlorine to vinyl chloride, preheating the ethylene/chlorine feed stream that exchanges heat with the fluidized bed combustion catalyst provides a more nearly adiabatic type of reaction. operation can be achieved. One-step chlorolysis or adiabatic ethylene/chlorine to vinyl chloride reaction and closed thermal loop (ClOsedhe
The preferred combination of steps of the present process, such as cold fluidized bed catalytic combustion of by-products in an at-100p) operation, provides a new and unique solution to heat waste or thermal energy loss.

The one-step vapor phase thermal chlorination of ethylene is highly exothermic, releasing its heat at temperatures high enough to decompose ethylene dichloride (EDC) to form vinyl chloride. The decomposition of EDC is an endothermic reaction. Theoretically, the two reactions should provide a small excess of heat, but the various heat losses and the heat required to preheat the feed streams preserve the net heat income to the process. is necessary. The closed thermal loop in which the ethylene and chlorine feeds are preheated by byproduct combustion reactions significantly reduces the net heat income required for chlorination/cracker operation. The oxyhydrochlorination reaction is also highly exothermic and is usually carried out in a fluidized bed reactor, so it is a steam generating system with significantly lower net pressure.

However, the EDC produced in the oxyhydrochlorination reaction is returned to the chlorination/decomposer where it is decomposed to vinyl chloride. The heat absorbed to decompose such recycled EDC must be fed to the chlorination/decomposer, and such thermal loads must be supplemented with the thermal energy required for the pinyl chloride recovery and purification train. is the main heat requirement of the entire process. The entire process thus requires a significant amount of natural gas to operate the known type of direct combustion tube cracker and gas-fired burner type by-product treatment furnace in terms of thermal energy costs. Significantly cheaper than vinyl methods. Also useful in the present process are vinyl chloride decomposition steps, such as the known process shown in US Pat. No. 2,724,006.

In such a process, a material commonly known as 6EDC1, which is a mixture consisting essentially of 1,2-dichloroethane and some 1,1-dichloroethane, is vaporized and the vapor is heated to about 450°C to 65°C, usually by means of a gas burner.
It is passed through a tube cracking furnace which is directly heated to a temperature in the range of 0°C. Typically no cracking catalyst is used, but there are prior methods that disclose the use of cracking tubes filled with either porous inert solids or other types of catalysts that are said to facilitate the reaction. In the absence of a catalyst, the reaction is a thermally induced decomposition whereby one molecule of hydrogen chloride is removed from each EDC molecule forming one molecule of vinyl chloride. In the decomposition reaction, the pressure ranges from 1 atm or slightly below to 28
It ranges from ~48 atmospheres.

The mixed steam from the cracking furnace is cooled to condense most of the chlorinated hydrocarbons. The recovered chlorinated hydrocarbons are then fractionated in one or more columns to separate hydrogen chloride, vinyl chloride, EDC, and impurities. In this fractionation, low- and high-boiling impurities or by-products are also separated, which are then fed to the catalytic combustion step of the process of the invention. The by-product hydrogen chloride is recycled to the oxyhydrochlorination step to produce additional EDC, which is converted into recovered unreacted EDC.
It is returned to the decomposition process along with the DC. Other known pyrolysis methods can also be combined with or used as a step in the present method. In any event, the effluent gas leaving the cracking furnace in each case is treated to recover and purify the desired cracked chlorinated hydrocarbon product, such as vinyl chloride. In the recovery and purification process, the product is condensed, optionally washed with water, and distilled and fractionated to remove the purified product overhead stream and unsaturated products such as high-boiling polychlorinated derivatives of ethylene, butadiene and chloroprene. It produces one or more often black colored and viscous bottoms streams containing dienes, aromatic hydrocarbons such as benzene, tarry residues and iron chloride impurities. Although the proportion of unwanted by-products produced by decomposition based on stoichiometric reactions is small, their proportion is nevertheless larger than that of by-products produced in the oxyhydrochlorination process; The cumulative total amount produced in commercial vinyl chloride equipment is large and presents significant processing problems. The present invention is therefore clearly an advantageous process since such a bottoms stream is an ideal feed to a catalytic combustion process and processing problems are therefore essentially eliminated. Furthermore, so-called direct chlorination reactions can be used as a step in the process, especially in conjunction with a catalytic combustion step.

In direct chlorination, ethylene or chlorinated derivatives of ethylene react with elemental chlorine in the liquid phase at low temperatures in the range of 20°C to 50°C to produce chlorinated derivatives with increased chlorine content. Catalysts such as iron chloride and others can be used in the reaction. In the reaction, about 1 mole each of ethylene and chlorine dissolved in liquid ethylene dichloride react violently with the release of heat to form 1,2-dichloroethane or ethylene dichloride (EDC). Similarly, 40℃~75℃
At slightly elevated temperatures in the range of , approximately equimolar ratios of EDC and elemental chlorine react to form tetrachloroethane, a precursor of both perchlorethylene and especially trichlorethylene. These products are usually fractionally distilled to remove unwanted by-products as a bottoms stream. These bottoms streams, which are particularly suitable, are then recycled to the catalytic combustion process of the present invention. When operating the present process using a fluidized bed in a catalytic combustion process, the combustion reactor is first charged with solid particulate alumina catalyst.

With the introduction of air that induces fluidization, the catalyst bed expands and thus goes from half-filled to almost completely packed depending on the volume of catalyst and the volume of air using the internal volume of the reactor. It can be changed between. The catalyst bed is fluidized prior to introducing the waste byproduct stream. In feeding the by-product stream to the reactor, the by-product stream is delivered to a position slightly above the bottom air inlet of the reactor. Preferably, the waste stream is sent to the reactor through a water-cooled nozzle that prevents vaporization and/or carbonization of this material prior to contact with the bed catalyst. In order to more clearly illustrate the present invention, the following specific examples are set forth, it being understood, of course, that these are illustrative only and not restrictive.

In the examples, all parts and percentages are by weight unless otherwise indicated. Example 1 The alumina catalyst used in this run had a surface area of 150M79m and was packed into a fluidized bed maintained at atmospheric pressure.

Atmospheric pressure was used to simplify operation within the operating equipment. However, it may be preferable to use superatmospheric pressure within the device. The amount of catalyst used was 265f! It was hot. supplying air to the reactor at a rate of 0.685 mol/hour;
The waste stream was then fed to the reactor at a rate of 2.82 cc/hr. The reaction was continued for 55 hours and the feed rate of the waste stream was fixed such that the contact time of the waste stream with the catalyst varied between 31.8 and 29.5 seconds. The temperature inside the reactor is 450
It varied between ℃ and 500℃. The waste stream consists essentially of the following materials: trans-1,2-dichloroethylene, 1
, 1-dichloroethane, cis-1,2-dichloroethylene, CHCl3, ethylene dichloride, 1,1,1-trichloroethane, carbon tetrachloride, 1,1,2-trichloroethylene, 1,1,2-trichloroethane , and tetrachlorethylene. The effluent gas leaving the top of the reactor as the catalytic combustion of the waste stream took place was analyzed chromatographically except for hydrogen chloride, which was analyzed titrimetrically with NaOH. Data for this operation are shown in the following table: The effluent gas stream can be used as obtained in the oxyhydrochlorination reaction.

An important advantage of the present invention is that it provides a new and improved method for the disposal of undesirable chlorinated by-products commonly obtained in the production of chlorinated derivatives of ethylene, such as the milling of vinyl chloride. That's true.

The method furthermore allows catalytic oxidation to recover the chlorine contained in the waste as hydrogen chloride, which can then be used in the oxyhydrochlorination step in the production of chlorinated derivatives of ethylene. It extends to Traditionally, hydrogen chloride has been recovered from the unwanted chlorination by-product by calcination. However, this method is very expensive and unreliable. Furthermore, such a method is extremely impractical since the cost of recovery is more than five times the market price of hydrogen chloride. A major component of the cost of such a process is related to the highly corrosive hydrochloric acid that is formed. If hydrogen chloride is dissolved in water, suitable construction materials are expensive, fragile, and result in high maintenance costs. On the other hand, the catalytic combustion step of the present process is economical in that no additional fuel is required, thus substantially reducing recovery costs. Catalytic combustion is also advantageous in the production of chlorinated derivatives of ethylene in that the temperatures used allow heat exchange of the generated steam or the thermal energy generated can be used for preheating the feed stream. be. Another advantage is that substantially no elemental or free chlorine is produced, so corrosion of the equipment is only trivial. Numerous other advantages of the present invention will be readily apparent to those skilled in the art. Although this invention has been described with particular embodiments, certain modifications and equivalents will be apparent to those skilled in the art and are intended to be included within the scope of this invention.

Claims (1)

[Scope of Claims] 1. A process for producing a chlorinated derivative of ethylene comprising an oxyhydrochlorination step in which hydrogen chloride is reacted with oxygen and ethylene or a chlorinated ethylene derivative; the separated stream into a fluidized bed of alumina combustion catalyst that is fluidized with air and maintained at a temperature in the range of about 400°C to about 500°C. to produce a hot combustion gas mixture containing essentially hydrogen chloride and essentially free of both elemental chlorine and chlorinated hydrocarbon materials, and subjecting the gas mixture to the oxyhydrochlorination process. chlorinated derivatives of ethylene, characterized in that at least a portion of the feedstock fed to the process step is used to remove heat from the combustion catalyst fluidized bed. Manufacturing method. 2. In the manufacturing method according to claim 1, the chlorinated derivative of ethylene is vinyl chloride, and the manufacturing method comprises (1) directly chlorinating ethylene at low temperature in a liquid phase to produce ethylene dichloride. (2) Approximately 450℃ to approximately 650℃
decomposing ethylene dichloride under pressure in the vapor phase at a temperature in the range of (3) to produce a mixture of vinyl chloride and by-product hydrogen chloride, and (3) in the oxyhydrochlorination step from step (2) of hydrogen chloride is combined with the hot combustion gas mixture and mixed with ethylene and oxygen to produce additional ethylene dichloride which is recycled to step (2). 3. The method according to claim 1, wherein the chlorinated derivative of ethylene is vinyl chloride, and the method comprises (1) reacting ethylene and elemental chlorine at 325°C to 460°C in the vapor phase. (2) in the oxyhydrochlorination step to produce ethylene dichloride and simultaneously decompose the ethylene dichloride to produce a mixture of vinyl chloride and by-product hydrogen chloride; Hydrogen is combined with the hot combustion gas mixture and mixed with ethylene and oxygen and heated from about 190°C to about 250°C.
A process comprising passing ethylene dichloride over a Deacon catalyst at a temperature of 0.degree. C. to produce ethylene dichloride which is recycled to step (1) for decomposition to vinyl chloride.