CA1236120A - Preparation of 2-halo-1-alkenes and acrylate esters from hydrocarbons streams - Google Patents

Abstract

ABSTRACT
A 2-halo-1-alkene (such as 2-chloro-1-pro-pene) is prepared by contacting together, in the pres-ence of a catalyst (such as alumina), (a) a 1,2-diene (such as propadiene) and/or a 1-alkyne (such as pro-pyne), with (b) a hydrogen halide (such as HCl); in the presence of at least 1,000 ppm water. The process of the invention provides unexpected selectivity for the desired product.

28,803A-F -18-

Description

~2;~

CATALYTIC

FROM UNS~TURATED HYDROCARBONS

The i~ention relates to an impro~ed process for the preparation of 2-halo-1-alkenes from light hydro-carbon streams.

Griesbaum, US 3,377,389, April 9, 1968, teaches ~hat hydrogen chloride and hydrogen bromide will add to u~satwrated compounds in accordance with Markovnikov's Rule and that allene ~propadiene) and methylacetylene (propyne) are hydrohalogenated to give

2-halopropene.

Kovachic and L. C. Leitch, "Organic Deuterium Compounds", Can. J. Chem., 39, 363-374 (1961) teach that 2-halo-1-alkenes can be prepared by addition of hydrogen chloride to 1-alk~nes. It is taught this addition can be performed in the presence of dibenzoyl peroxide or under ultraviole~ illumination.

28,803A-F ~1-~L2361%~ ' .
Arganbri~ht, US 3,142,710, teaches that propyne and propadiene can be selectively halogenated in the presen~e of propylene (propene). Propylene con-taining minor amounts of pxopyne and propadiene together with hydrogen chloride are passed over a catalyst com-prising mercuric halide deposited on a porous carrier, particularly one having high surface activity at a tem-perature in the range of from about 100C to about 120C.

Schroeder and Slewka, French Patent 1,505,099 10 ~December 18, 1965), teach that a C3 hydrocarbon stream may be purified by selectively removing propadiene (allene) and propyne (methyl acetylene) by reacting the C3 hydrocar~
bon stream with hydrogen chloride in the presence of hydro-chlorination catalysts, in particular mercuric chloride on a support such as activated aluminum oxide, silica gel or activated carbon. The propadiene and propyne are selec-tively halogenated to prepare 2-chloropropene which is easily separated from the other components of the C3 light hydrocarbon stream.

Herbertz, "Von Aliphatischen Acetylenkohlen-wassersto~fen ausgehende 5ynthesen", Chem. Ber., 92, 540--50 (1959), teaches two processes for the addition of hydroge~ halides to alkynes. One is a mixed-phase reac-tion wherein copper (I3-chloride is the catalyst. In the othar, the alkyne is vaporized and mixed with hydro-gen chloride and passed over activated charcoal in the presence of mercury at ~ temperature of 130C.

A process has now been discovered for selec-tively halogenating a 1,2-diene and a terminal acetyl-ene with a hydroyen halide in the presence of othex 28,803A-F -2-" , ~2~2al hydrocarbons wherein the yields of the 2-haloalkenes are substantially higher than prior art processes per-mit. The 2-halo-1-alkenes prepared by this process can be carbonylated and esterified to prepare acrylate esters if desired.

One such acrylate ester is methyl methacry-late which is prepared commercially from acetone which is treated with HC~ to give 2-cyano-2-propanol which is then treated with 98 percent sulfuric acid to give a salt of propene-2 amide and sulfuric acid. The salt is then reacted with methanol to prepare methyl methacrylate and N~4HSO4. This process requires a large purification scheme and the use of sulfuric acid and hydrogen cyanide.
It is desirable to prepare methacrylates without the use of sulfuric acid and hydrogen cyanide.

Brie~ly, the invention is a process or pro-ducing a 2-halo-1-alkene by contacting together, in the presence of a catalyst: (a) a 1,2-diene and/or a 1~
kyne; and (b) a hydrogen halide; in the presence of at least 1000 ppm water. The process of the invention unexpectedly provides greater selectivity than prior processes. This increased selectivity was even more unexpected when the inventors of the instant invention discovered the previously unreported fact that ~he unsaturated hydrocarbon streams used in the analogous prior art processes inherently contain up to about 75 ppm of water.

In this invention, a hydrocarbon stream com-prising a 1,2-diene, a 1-alkyne, or mixtures thereof, is reacted with a hydrogen halide to prepare a 2-halo-1-al-kene. This can be represented by the following equations:

28,803A-F -3-~ -4-~;316~2~) CH2=C=C~R ~ HX catalyst~ CH2 2 (I) or 2 catalyst CH2 C CH2R (II) whexein X is chlorine, brsmine, iodine or fluorine; and wherein R is hydrogen, alkyl, cycloalkyl, or ar.yl, and 10 may be substituted or unsubstituted. Such substitution is limited, of course, to those moieties which will not cause substantial chemical or sterical interference with the reaction. Since the prior art reactions employ reac-: tants similar to those used in this inven~ion, suitable ; 15 substituent moieties will be apparent to those skilled in the art. The 2-halo-1-alkene can be separated from the unreacted hydrocarbons, hydrogen halide and any by-: -products by conventional means, such as distillation.

The hydrocarbon streams as used herein can contain saturated alkanes, alkenes, dienes and alkynes.
A C3 hydrocaxbon stream as used herein can contain pro-pane, propylene, propadiene and propynes with minor amounts of C~, C4 and C5 aliphatic compounds. In such streams, the active species are the 1,2-dienes and the l-alkynes.

:The hydrocarbon stream which is halogenated preferably comprises a 1~,2-diene of e~uation I, terminal acetylene of equation II, or mi~tures thereof 5hereinafter 28,803A-F -4-. .

~:36~2~
referred to as active species) wherein R is C1 to C10 alkyl ~r hydrogen. More preferably, R is hydrogen; thus the 1,2-diene is preferably propadiene and the 1-alkyne is pr~ferably propyne. In this more preferred embodiment, any hydrocarbon stream containing propadiene, propyne, or a mixture thereof can be used. A hydrocarbon stream con-si.sting essentially of propadiene and propyne can be used, but it is preferable that the hydrocarbon stream have less than 65 percent of these active compounds, as abov~ this concentration, such a stream is explosive. A hydrocarbon stream o~ C3 compounds including the active species is a good starting stream.

2-Halopropene is produced where the hydrocar-bon stream is a C3 stream containing propadiene, propyne or mixtures thereo~.

The hydrogen halide can be hydrogen bromide, hydrogen chloride, hydrogen iodide or hydrogen fluoride.
~ydrogen chloride and hydrogen bromide are preferred.

The halogenation of the active species in the hydrocarbon stre~m can be done in eith~r the li~uid phase or the vapor phase. The vapor phase is preferred because in the liquid phase highex concentrations of the active species may be present, increasing the risk of explosion.

Surprisi~gly, suitable catalysts include car-bon, silica alumina, silica gel, silica magnesia, silica-lite, aluminosilicates, group IIIA, IIIB, IVA, IVB or V
metal oxides ox rare earth oxides. The catalysts may be impregnated with mercuric halide or barium bromide as is taught in US 3,142,710, but contrary to the teachings in that patent, such compounds are not necessary to catalyze 28,803A-F -5-36~LZ~

this reaction. Preferred catalysts are carbon, silica alumina, silica gel, silica magnesia, silicalite, alumino~
silicates, and group IIIA oxides. ~ore preferred are car-bon and alumina. The most ~referred catalyst is alumina.
The catalyst has a significant effect on the select.ivity of the insertion of ~he halogen on the unsaturated active species in the hydrocarbon stream. Those aluminas with high surface area, high acidity and with low silica con-tent demonstrate the best activity.

These catalysts can be regenerated by passing water saturated air through the catalyst for a period of several hours at elevated temperatures. Preferably, the catalyst i~ regenerated by passing water vapor and an o~ygen-containing gas over the catalyst at between about 350C and 500C for between 2 to 24 hours.

It has been discovered that the presence of water in the halogenation of the active unsaturated hydro-carbons maintains the selectivity of the catalyst during prolonged use. Furthermore, the presence of the water unexpectedly reduces rate of deactivation of the cata-lyst. After a short period, four or five hours, the selectivity of the catalyst drops si~nificantly in the ab~ence of water. The use of water during the process maintains the selectivity of the catalyst over the cata-lyst lifetime.

Only a relatively small amount of water isnecessary. That amount of water which is capable of maintaining the selectivity of the catalyst for the insertion of the halide on the 2 carbon of the 1,2-diene or 1-alkyne is sufficient. Preferably, water is pre~ent at between 1,000 and 100,000 parts per million by weight, 28,803A~F -6-~;23~

and more preferably between 3,000 and 30,000 parts per million by weight, based on the weight of the hydrocar-bon feed stream. The water can be added by any manner known in the art which provides sufficient water to main-tain catalyst selectivity and reduces the rate of catalyst deactivation The water can be added continuously or intermittently. In fact, if the water level is allowed to drop below that level at which the advantages of this invention are achieved, subsequent addition of water to raise the water level to the levels at which such advan-tages occur will result in such advantages occurring. In one embodiment, the water can be pumped in~o the reactor either continuously or intermittently. In anothex embodi-ment, water addition may be achieved by saturating the hydrocarbon stream with water vapor prior to contacting it wi~h the hydrogen halide and the catalyst.

The hydrogen halide can be added in any ratio to the active unsaturated compounds in the hydrocarbon stream~ A desirable molar ratio is between 0.7 and 1.5 moles of hydrogen halide per mole of active species.
The use o excess hydrogen halide may xesult in the halo-genation of compounds in the hydrocarbon stream other than the active unsaturated species and the preparation of 1,2-dihaloalkanes from the active species.

This process can be run over a wide range of temperatures and is desirably run at between -78C and 400C. It has been discovered that a preferable temper-ature range is between 100C and 300C. Below 100C
selectivity is reduced and above 300C little improve-ment in selectivity is found. Above 400C there is 28,803A-F -7-` -8-~L~36~

considerable degradation of the catalyst. Most prefer-ably the temperature is between 200C and 300C as selec-tivity is at its optimum in this range. In the vapor phase process where the streams of reactants are passed over the catalyst it is desirable to preheat the streams to the reaction temperature prior to pas~ing them over the catalyst.

This step may be run at subatmospheric, atmos-pheric, or superatmospheric pressure. It is believed ~hat superatmospheric pressures would improve the rate of reac-tion.

The 2-halo-1-alkenes prepared by the invented process can be isolated by conventicnal means and carbon~
ylated and esterified to prepare an acrylate ester.
.

Example 1 - Hydrobromination of a Crude C3 Stream Using Alumina Through a tube reactor, heated to 21~C at atmospheric pressure and loaded with 15 cm3 of alwmina plus inert quartz chips packing, was passed 27.5 ml/min of ~Br gas and 90.0 ml/min of a crude C3 stream satu-rated wi~h water vapor (10,000 ppm). The molar composi-tion of the C3 stream was 16.8 percent propadiene, 22.8 percent propyne, 52.4 percent propyle~e, 6.5 percent pro-pane and 1.5 percent mixed C4 hydrocarbcns. Approximately 65 percent total propyne and propadiene conversion was achieved with about 95 percent selectivity to 2-bromopro-pene.
:

28,803A-F -8-~o~

Exam~le 2 Hydrochlorination of a Crude C Stream Using Alumina 3 Through a tube reactor, heated to 290C at atmospheric pre~sure and loaded with 50 cm3 of alumina plus inert guartz chips packing, was passed 73.0 ml/min of HCl gas and 150 ml/min of a crude C3 stream saturated with water vapor (10,000 ppm). The molar composition of the C3 stream was 24.0 percent propadiene, 27,2 percent propyne, 18.8 percent propylene, 23.4 percent propane and 6.6 percent mixed C4 hydrocarbons. Approximately 73 percent total propyne and propadiene conversion was achieved with approximately 98 percent selectivity to 2-chloropropene.

Examples 3-10 Exa~ples 3-10 were run in a manner similar to Examples 1 and 2. The results are compiled in Table I.
In Table I, actives conversion refers to the percentage of propyne and propadiene which was halogenated and selec-tivity refers to the percentage of the 2-halopropene in such haloge~ated compounds.

~ able I demonstrates that in the process of the invention, alumina is preferred over carbon. Fur-ther, Ex~ples 1-3 demonstrate that the presence of water increases the selectivity of the reaction for 2-halopropene.

Table II shows the composition of the C3 stream of Examples 1 to 10.
.

28,803A-F -9-~3~ 0 0 0 ~ ~ ~ OD ~ C~
J) ,,

3, U~
o ~ In ~ Ul O N 0 1~1 ~I Ll^) O
o O O O O O O ~ O O
~ 3 ~-e U h ~ 1 I c~ u~ o ~ ~ o o o U~ ~
a~ u~ o o u~ Ln o o c~ o o ~
h N t~ ~1 ~ Nt~ ) ~ N N

~ o H ~ Q a) ~D O O O O O O O
~;3 3 O O U) U~ O ~
~ ~ ~1 o~ N ~` ~1 ~D
a~ o ~ ~`I N N N N
E~
~ ~ .

~, pq ~ .
o h ~
Q~ h rl rl rlO ~ ~ O O ~ O ~1 h rl ~ h ~1 ~1 ~t~ h G~
3 0 ~
~,) ~ N U~ U~ E-l E U
~ a~ o 5-1 _I h h h h h h * * K * ~I~ * K
Z ~I N ~ d~ ul ~D L~ 0 a) O
~$ *~

28, 803A-F . -10--TABLE II
~ .
Composition of C3 Streams E~amples 1~10 Propa- Pro- Pro- Pro- ~yd40-diene yne pylene E~ carbons 1 and 5-9 16.8 22.8 52.4 6.5 1.5 : 2 24.0 27.2 18.8 23.4 6.6 3 11.7 14.4 46.6 27.0 0.
10 4 and 10 16.4 20.6 54.6 6.8 1.5 Examp~ Effect of Temperature on the Selectivlty : of the Halogenation of a C3 Hydrocarbon Stream to 2-Chloropropene A C3 hydrocarbon stream containing propadiene and propyne and a stream of HCl were passed over an alum-ina catalyst for 98.5 hour~. The C3 stream was bubbled through water (to provide 10,000 ppm water~ prior to pass-ing over the catalyst. The temperature was gradually increased from 155.1C to 307.8C over the 98.5-hour per-iod. Periodic samples were taken and analyzed. Table IIIshows the effect of temperature on the selectivity or 2-chloropropene of the chlorinated methyl acetylene and propadiene.

28,803A-F -11-.- ~2~
TABLE III

Time Temp. Selectivity C ~2 6.00 155.6 50.8 9.2~ 177.6 71.5 13.75 198.0 84.8 17.50 216.0 92O1 31.25 231.0 93.g 52.30 231.0 91.1 10 63.00. 251.7 98.2 77.45 271.1 g8.5 86.00 331.1 98.8 9~.25 307.8 ~ 97.5 This demonstrates that selectivity improves with an increase in temperature and that above 300C
there is little improvement in selectivity.

Effect of Water Vapor on the Selectivity of the Halogenation of a C3 Hydrocarbon Stream to 2-Bromopropene A C3 hydrocarbon stream containing propadi-ene and propyne and a stream of HBr were passed over an alumina catalyst for 20.3 hours at a temperature ranging ~rom 250C to 303C. The hydrocarbon stream was bubbled through water (to provide 10,000 ppm water) prior to pass ing it over the catalyst. Table IV shows the selectivity over time.

28,803A-F -12 ~:36~
TABLE I~

Selectivity for Time2-Bromopropene (hours)(7QL_ 2.0100.0 3.0100.0

4.5 99.~

5.5 95.9

6.5 g3.0

7.5 91.5

8.5 93.9

9.5 9200

10.~ 91.3 14.0 94.1 15.0 93.9 16.3 9501 la.3 95.2 19.3 94.1 : 20.3 93.0 A C3 hydrocarbon stream containing propadiene and propyne and a stream of HBr were passed over an alum-; ina catalyst for 23.5 hours at a temperature ranging from 200C to 220C. The C3 stre~m was not bubbled through water. The selectivity over time is shown in Table V.

28,803A-F -13 .

~ -14-~36~2~

TABLE V

Selectivity for Time 2-Bromopropene (hours) (%) S 2.1 100.0 5.5 97.6 .6 93.5 .5 90.1 ~.5 86.0 10 9.4 83.7 10.4 80.9 14.3 73.0 15.4 71.2 17.6 6~.5 1518.5 67.9 1~.4 66.4 20.4 64.7 The above data demonstrates that the presence of 10,000 ppm of water kept the selectivity of the reac-~ 20 tion for 2-bromopropene above 90 percent, whereas in the : abs~nce of the water, the selectivity of the reaction steadily decreased to 65 percent over the 20.3-hour per-iod. This demonstrates that the presence of water has a significant effect ir. maintaining the selectivity for 2-bromopropene above 90 percent for a longer period of time.

28,803A-F -14-36~
Example 13 Through a tube reactor loaded with 10 cm3 of y-alumina catalysts and heated to 290C, is passed HC1 at a flow rate of 55 cm3/min, and a C3 stream at a flow rate of 200 cm3/min. The pressure is 5 psig ~34 kPa, gauge). The C3 stream comprises 18.19 percent allene (propadiene), 22.23 percent methyl acetylene (propyne), 1.39 percent isobutylene, 7.61 percent propane, 45.76 percent propylene, and 4.13 percent N-butane. Water is added to provide a water concentration of 3,900 parts per million. The process is repeated at a water concentration of 75 parts per million and 12,000 parts per million. The rate of deactivation of the catalyst is calculated at each concentration. The results are compiled in Table VI.

TABLE VI

Water Deactivation Concentration Rate Percent p~m per hour 20 75 1.8 3,900 0.36 12,000 0.07 28,803A~F -15-

Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for preparing a 2-halo-1-alkene comprising contacting together in the presence of a cata-lyst, (a) a 1,2-diene of the formula CH2=C=CH-R, a 1-alkyne of the formula CH=C-CH2-R, or a mixture thereof, wherein each R independently represents a substituted or unsubstituted moiety comprising hydro-gen, alkyl, cycloalkyl, or aryl; and (b) a hydrogen halide;
characterized in that there is present during the reac-tion, at least 1000 ppm of water.

2. The process of Claim 1 wherein the cata-lyst comprises carbon, silica alumina, aluminosilicates, silica gel, silica, silica magnesia, silicalite, group IIIA, IIIB, IVA, IVB or V metal oxides or rare earth oxides.

3. The process of Claim 2 wherein the cata-lyst is carbon or alumina.

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4. The process of Claim 1, 2 or 3 wherein the reaction is conducted in the substantial absence of mercuric halides, copper halides, aluminum halides, iron halides, zinc halides, bismuth halides, nickel halides or calcium halides.

5. The process of Claim 1, 2 or 3 wherein R is H or C1 to C10 alkyl.

6. The process of Claim 1,2 or 3 wherein the 1,2--diene is propadiene, the 1-alkyne is propyne and the 2-halo-1-alkene is 2-halopropene.

7. The process of Claim 1 wherein the hydro-carbon stream is contacted with the hydrogen halide in the vapor phase.

8. The process of Claim 1 wherein the tem-perature is between 100°C and 400°C.

9. The process of Claim 1 wherein the hydro-carbon stream is saturated with water prior to contacting the stream with hydrogen halide and the catalyst.

10. The process of Claim 1 wherein the water concentration is between 1,000 and 100,000 parts per million by weight.

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