JPH01290646A - Carbonylation of propylene - Google Patents

Abstract

PURPOSE: To convert substantially all of propylene and CO into isobutyl fluoride by subjecting a product of carbonylation among propylene, CO and HF to gas/ liquid separation and subjecting a liquid stream containing unreacted CO to a carbonylation reaction in the second reactor.

CONSTITUTION: Propylene, CO and HF arc fed into the first reactor 11 and subjected to a carbonylation reaction, the obtained effluent 12 is separated (13) into an overhead gas stream and a liquid stream containing unreacted CO, and the liquid stream 21 is fed to the second reactor 22 and reacted with propylene 19 and part 18 of the gas stream from the phase separator 13. The effluent 23 is separated (24) into an overhead gas and a bottom liquid, and the bottom liquid is introduced into a degassing pot 40 and stripped of an overhead gas to recover isobutyl fluoride as a bottom liquid. Part of the overhead gas from the phase separator 24 is sent to a refrigerator, the bottom stream comprising lowly volatile substances is separated, and part of it is recovered as isobutyl fluoride.

COPYRIGHT: (C)1989,JPO

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is directed to carbonylating propylene with carbon monoxide in the presence of hydrogen fluoride to obtain imbutyryl 70lide (
1sobutyryl fluoride), and in particular to the optimal use of carbon monoxide.

[Conventional technology]

The production of isobutyric acid and isobutyryl fluoride by the Kotzho reaction is well known to those skilled in the art. U.S. Patent i (li
, li 99.029 discloses an excellent method for the production of isobutyryl fluoride, in which propylene, carbon monoxide and hydrogen fluoride are reacted in a continuous flow reactor and the There are multiple injections of propylene and carbon monoxide between the reactors.

Conventional methods of producing isobutyryl fluoride by the Kotsuto process have been shown to have yields and conversions of 7j1b. And it is said that in many cases high product conversions are obtained based on the consumption of propylene.

In most cases of prior art disclosures, the product yield and conversion based on carbon monoxide consumption were very low. For example, US Patent No. 11. See No. L152.999, column 5, lines 35-56, 1 etc.

[The problem that the invention attempts to solve]

Unreacted carbon monoxide has been considered a consumable.

And it has usually been thrown away along with the waste gas. The present invention aims at maximizing the use of carbon monoxide in terms of its value and thus significantly reducing the production costs of isobutyryl fluoride.

[Means for solving gland problems]

To achieve the above object, the present invention provides a process that fully utilizes both propylene and carbon monoxide, even if the propylene used is not pure and contains foreign gases. Pure propylene is always more expensive than the lower grade propylene mixtures often obtained from petroleum refineries. Low grade propylene may also contain gases such as ethane, ethylene, propane isobutane, etc., which are for the most part inert to the Kotsho reaction. The present invention provides that the Kotsuto reaction can be carried out in an equally satisfactory manner when using pure propylene or a mixture of cheap propylene, and in both cases there is a substantial amount of propylene and especially carbon monoxide in the feedstock. can be converted to the desired isobutyryl fluoride.

〔Example〕

Embodiments of the invention will be described with reference to the drawings, in which gaseous carbon monoxide (CO) is introduced into the process stream in line 1 and in a COI/'i compressor 2 with approximately 5
5-210 immediate/c-j (500-5000ps1a)
, preferably in a pressure tube of about 55 to 70 cm/-. Since both the environmental temperature and the process temperature are higher than the dew point temperature of the normal OOIJ Latch mixtures encountered industrially,
Condensable components at these pressures generally do not occur. If condensable components are present, they can be removed by known methods before entering this step. Industrial grade CO often contains trace amounts of N, + H, Co, and 0 snow. The trace amount of oxygen present in CO is 1
It can be easily removed, for example, by suction devices well known in the art. Preferably, the CO used in the method of the invention is oxygen-free. Propylene (03H) is
It is introduced as a liquid via line ++6 into a pressurizing pump 5, which is capable of achieving the process pressure of the CO in the process. Typically, propylene is liquid and pumped, but the use of gaseous propylene is also within the scope of this invention. As in the case of CO, condensable components such as water can be removed from the propylene before entering the process stream. The water.

It can be easily removed from the propylene by well-known absorption equipment, which is outside the scope of the present invention and not shown.

The main portion of the pressurized propylene leaving pump 5 is removed as stream 6, which is mixed with pressurized carbon monoxide, shown as flowing out of compressor 2. The combined stream can be two-phase or one-phase (depending on temperature, pressure and composition).
(preferably all in the gas phase) as stream 7.

The purpose of the mixing in stream 7 is to make the stream sufficiently uniform to allow one or more portions of stream 7 to be removed, as represented by stream 8.

The fluid-dominated hydrogen fluoride-rich stream is a mixture of hydrogen fluoride (HF) 7 recirculated from downstream recovery equipment and make-up hydrogen fluoride (HF) 9 necessary for the process to maintain continuous operation. Prepared as a mixture.

The pressurization device ItVi for stream 9 is not shown, but may be provided by any suitable pump known in the art. The H F IJ latch bodies in stream 9 contain impurities resulting from those contained in the make-up feed or the overall composition of the streams contacted in the process.

A gas-dominant stream is also recycled from a downstream source, as shown by stream 10. The composition of stream 10 is subject to considerable control.

and primarily the amount of gaseous impurities allowed in all of the feed streams;
It depends on the solubility of such impurities in liquid process stream 21 and on the type of fractionation of stream 16 selected for recirculation as a recycle loop through valve 17. Stream 10 may contain large or small amounts of gases such as carbon monoxide, nitrogen, carbon dioxide, isopropyl fluoride, hydrogen, helium, neon, propylene-HF-, and the like. Flow to Vic
Although it is desirable that the o content is predominant.

It usually contains a lower concentration of CO than the CO in stream 1.

Stream 10tri is mixed with sufficient strength to produce a well-dispersed gas and liquid mixture (preferably the gas phase in the mixture is more continuous than the liquid phase). This well-dispersed gas-liquid mixture is initially fed together with stream 8 to the inlet of reactor 11. The importance of recycle stream 10 is to avoid side reactions in which one propylene reacts with other propylene or derivatives of propylene to form dimers and higher oligomers of propylene or carbonylated or H7-thinated derivatives of propylene. or provide sufficient gas phase dilution of propylene to substantially eliminate it.

The reactor 11 is characterized by having one or more stages connected in series such that the effluent from the previous stage becomes the feed stream to the next stage. The reactor 11 is.

It is also characterized in that a seed portion of stream 7 can be separated from stream 7 in the same manner as described for stream 8 so as to be introduced as co-feed to the 36 stages of the reactor.

Although the illustration shows one reactor 11 as a plug flow device for simplicity and low cost, this should not be interpreted to mean that other reactor configurations cannot be used within the scope of the invention.

The reactor effluent, represented by stream 12, includes all feed and a minor recycle stream of reactants converted to other products, plus new products (primarily isobutyryl produced in the reactor).
Fluoride). Stream 12Vi, generally a mixture of gas and fluid, containing 50% or more by volume of gas Fi;
It is often of the order of 90% by volume of the mixture, especially when using plug-flow reactors.

The material in stream 12 is fed to a phase separator 13, which includes an empty vessel containing a screen or other impact reduction device, a centrifuge, and stream 21 is substantially free of entrained gases. and gas and liquid under moderately high pressure, such as a device characterized by sufficient separation of the gas predominance so that the compressor or blower 15 can operate effectively as a pressure booster for recirculating flow. The device can be designed to be suitable for the separation of The noble pressurized stream of stream 16 from blower 15 may be recycled entirely to the reactor as stream 10, or some portion of stream 16 may be recycled to the main (or - next) can be divided and removed from the gas recirculation loop via valve 17; If valve 17 is not provided, the only outlet for gaseous impurities is.

via the solution of the liquid part leaving the phase separator 15. As a result, the omission of valve 17 eliminates the sum of all gaseous substances and/or impurities in the feed and recycle streams entering or produced within the reactor.

In particular, the partial pressure of the reactants containing CO and propylene must be below the solubility limit of impurities in the liquid stream leaving the phase separator after correction. The presence of valve 17 should not be interpreted to mean that the single method is limited to feed concentrations of impurities that exceed the solubility limit.

Adjustment of valve 17 allows the use of feedstocks of varying purities and necks ranging from very pure to extremely impure, thus providing a process with wide flexibility as well as economy.

A portion of the pressurized propylene from pump 5 is taken as stream 19- and is thoroughly mixed with the highly gaseous recycle stream 1g described below. The mixing, temperature and pressure intensities are sufficient to provide good dispersion of the liquid portion in the gas phase and sufficient to preferentially vaporize the propylene to produce a highly gaseous stream 20. It is a value. The purpose of the 1 g recycle stream is to avoid side reactions in which propylene reacts with propylene or derivatives of propylene to form dimers and higher oligomers or carbonylated or fluorinated derivatives of propylene dimers and higher oligomers. In order to achieve sufficient dilution and dispersion of one propylene stream.

Streams 20 and 21 are fed simultaneously to reactor 22.

The reactor 22 is suitable for sufficient contact between gas and liquid when the volume fraction of gas is 1% or more than 50%. In the method of the invention, carbon monoxide is.

Addition of additional propylene reactant via stream 1 of stream 23 leaves the reactor resulting in the desired carbonylation reaction consuming both carbon monoxide and propylene! 1
The degree of reaction is sufficient in the direction of extinction, which results in a very economical process when compared to methods of producing the desired product without reacting or stripping or dissolving the carbon monoxide in the liquid phase or reacting the entrained carbon monoxide. can do.

The process of the invention significantly improves product retention with respect to carbon monoxide in the feed. The effluent 23 from the reactor 22 is sent to an empty container or to a container with a screen for impact coalescence of the droplets or to a centrifuge.

The liquid is supplied to a phase separator 21i, which is a device suitable for separating gas and liquid at moderately high pressures such as the like.

The phase separator 211 ensures that (1M phase does not substantially mix gases, (2) back-mixing of gas and liquid after phase separation is kept to a minimum, and (5) dissolved in the liquid phase. The present invention is characterized in that sufficient liquid maintenance is provided to allow the residual carbon monoxide to react.

A means by which such an objective is further carried out and controlled is by recycling a well-controlled portion of the substantially gaseous effluent stream 25 from the phase separator 211. Recycled gas 26 is repressurized with blower or compressor 8!27 and mixed with vent gas taken through valve 17 to produce stream 1g. CO required for the liquid phase present in the phase separator 21+
The concentration of is usually controlled so that it reacts and disappears.

Such 009 degree control in the liquid phase is achieved by the phase separator 214.
by controlling the partial pressure of CO in the gas phase stream 25 exiting the gas phase stream 25. and flow 25Vi followed by cooler 2g
and a recirculation loop through valve 29 can be controlled by the portion of flow 25 that is exited. The magnitude of the flow through the two valves is determined by the sum of the gaseous impurities introduced via the feed stream or generated through reactions within the process in order to obtain stable or steady-state operation continuously. related to

The gases exiting from the two valves contain valuable substances, including HF-00, propylene and volatile intermediates, as well as substances harmful to the environment. Means are included for introducing such components into the column 50 and condensing them by contacting the ascending gas with the descending refrigerated liquid to limit losses of the components by creating less volatile components. 1 g of the frozen liquid was collected in column 50 and stream 31. Pump 52.
and by removing it via stream 55. Stream 53 is mostly recycled as stream 35 through refrigerator 311i to maintain sufficient liquid inventory. Uncondensed gas exits column 30 as stream 36. Stream 36 is then processed for further processing or environmental purposes. valve 2
A liquid stream equal in mass to the condensable portion of the flow through the two is removed as stream 57 and mixed with the liquid stream 38 from the phase separator 211 after depressurization through three valves. Phase separator 2I
Stream 58 from I becomes saturated with gaseous components only to the extent that the total inert material conveyed to reactor 22 and vessel 211 exceeds the solubility limit of the liquid stream.

Flow through the two valves can only exist with respect to sustain when such a surplus exists with respect to sustain. Therefore, when the feedstock is of very high purity, valve 1
The feed through 7 is not sufficient to maintain the gas recycle stream 25 at t and composition. For special cases,
When all feedstocks are of very high purity, optional means may be provided alone or in combination to maintain stream 25, such as: The gas contained in the gas spot 11O is phase-separated.

Such gas can be recompressed in compressor 41 and recycled via stream 112.

(bl Gas collected from downstream equipment flows through stream 113
It may contain acceptable inert ingredients suitable for recycling as indicated in . The presence or absence of the degassing bot 40 is a limitation of the invention insofar as it is effective as a means by which downstream equipment, such as a distillation column, can degas the liquid stream and recycle a portion of the gas. should not be interpreted as such.

+01 Inert gas from normal sources is! Flow 115 can be introduced for recirculation as shown by stream 115. Flow 1! II contains HF and the product isobutyryl fluoride (IBF) which goes to a recovery unit not shown. Efficient and economical to perform one or both without the undesirable consequences of discarding useful intermediates in a wide range of practical applications in terms of feedstock purity and more complete use of CO feedstocks. It is for the purpose of providing the means for the expression of these teachings. It is not counterproductive to the high utilization of mixed impurities 1jco in feedstocks with less requirement for liquid saturation according to the present invention.

[Brief explanation of the drawing]

The drawing is a schematic explanatory diagram of an apparatus used in the method of the present invention.

Claims (1)

Claims: 1. A method of feeding propylene, carbon monoxide and hydrogen fluoride to a first carbonylation reactor to produce a gas/liquid effluent containing isobutyryl fluoride, comprising: (A ) introducing the effluent into a first phase separator to separate the effluent into an overhead gas stream and a bottom liquid stream containing unreacted carbon monoxide; (B) from step (A); (C) introducing the lower liquid stream of the second reactor into contact with the propylene-containing gas stream to react essentially all of the carbon monoxide; (C) the second reactor in step (B); (D) introducing said bottom liquid stream into a second phase separator to separate overhead gas from a bottom liquid;
(E) from step (D), introducing the bottom liquid stream into a degassing pot where the overhead gas is removed and the bottom liquid is essentially isobutyryl fluoride. Take the overhead gas flow,
If necessary, a make-up inert gas is added to the gas stream, and this gas stream is then recycled to the hydrogen fluoride fed to the first reactor, and/or this gas stream is added to the gas stream in step (B). (F) directing the overhead gas stream from step (A) to a compressor and then to the recycle gas stream from step (E); (G) step (C) Take overhead gas from
The first portion is recycled in step (E) and the second portion is sent to a refrigeration system, the second portion is separated into a lower volatile material stream and a volatile material overhead stream, and the second portion is separated into a lower volatile material stream and a volatile material overhead stream. and (H) taking and discarding a low volatility overhead material stream from step (G) to produce carbon monoxide and propylene of varying purity. A process for the carbonylation of propylene featuring improvements in the use of. 2. The method of claim 1, wherein the effluent is a mixture of 50-90% by volume gas.