DE1793247C3 - Process for the production of alkylene glycols - Google Patents

Description

R ₂ -NR ₃

in which R ₁ , R ₂ , R ₃ , R _{4 is} hydrogen, alkyl or a combination thereof and X is chlorine, bromine or iodine, or of substances which form these catalysts on hydration.

2. The method according to claim 1, characterized in that the catalyst in an amount of 0.1 to 5% based on the weight of alkylene oxides and water is used.

3. The method according to claim 1 and 2, characterized in that the reaction is additionally in Presence of basic compounds in an amount of 0.1 to 2% based on weight of alkylene oxides and water.

4. The method according to claim 1 to 3, characterized in that alkylene oxides and water can be used in a molar ratio of 1: 1 to 1: 1.3.

The yield of monoalkylene glycols in the known processes is about 90 percent by weight the theory.

The aim of the present invention is to eliminate the drawbacks mentioned.

The invention was based on the object of a process for the production of alkylene glycols to develop that makes it possible to carry out the process with little or no excess water ■ .ο and the yield of monoalkylene glycols increase about 97 weight percent of theory.

This object is achieved in that in the process for the preparation of alkylene glycols by catalytic hydration of alkylene oxides with heating, the hydration of the alkylene oxides according to the invention in the presence of carbon dioxide under a pressure of 10 to 180 atm at a temperature of 80 to 220 ⁰ C using as a catalyst of alkali metal halides or compounds of the general formula

The invention relates to processes for the production of alkylene glycols.

Processes for the production of alkylene glycols by catalytic hydration are known the alkylene oxides under heating.

So is z. B. a process for the production of ethylene glycol by catalytic hydration of the Ethylene oxide at a temperature of 2 (30 to 400 ° C with the use of calcium phosphates known as a catalyst (see German Patent 028 979).

A disadvantage of the known methods is that it is necessary to use a large excess of water to consume (molecular ratio of alkylene oxide and water is from 1: 6 to 1:17) in order to use it avoid the formation of di-, tti- and polyalkylene glycols. Because of the large excess of water only 15 to 20% strength (at best 35% strength) aqueous alkylene glycol solution is obtained. To be focused To obtain alkylene glycol, one has to distill off water, which requires a great deal of energy as well as substantial investments in the construction of large-scale facilities. So you have to distill off about 4 to 61 water to produce 11 ethylene glycol.

R ₂ -NR ₃

in which R ₁ , R ₂ , R ₃ , R _{4 is} hydrogen, alkyl or a combination thereof and X is chlorine, bromine or iodine, or of substances which form these catalysts on hydration.

As an example of the compounds of the general formula mentioned, tetraalkylammonium halides can be used (Tetramethylammonium iodide, tetraethylammonium

momumbromid), amine hydrohalide (triethylamine hydroiodide, Propylamine hydroiodide, diethylamine hydrochloride).

Of the mentioned groups of compounds show bromides and iodides, which are used as catalysts will get the best results.

In order to "obtain the stated catalysts in the reaction mixture", substances which form these catalysts can be added to the same.
Examples of these substances are a mixture of triethylamine and ethyl iodide, which forms tetraethylammonium iodide, a mixture of ethylene iodohydrin and potassium carbonate, which forms potassium iodide, a mixture of tripropylamine and propyl bromide, which forms tetrapropylammonium bromide, a mixture of propylene bromohydrin, which forms sodium bromohydrin and sodium bromide to name. It is advantageous to use the stated catalysts in an amount of 0.1 to 5%, preferably 0.3 to 1.5%, based on the weight of the mixture of alkylene oxides and water.

In order to reduce the formation of dialkylene glycols and to speed up the process, the Hydration of alkylene oxides in the presence of basic compounds, e.g. B. carbonates, bicarb

nates and alkali metal hydroxides ^ which in an amount of 0.1 to 2%, based on the weight of the mixture of alkylene oxides and water, taken are carried out. Under the reaction conditions d. H. in aqueous solutions under the pressure of carbon dioxide, all of our proposals are found basic compounds, alkali hydroxides, alkali carbonates and bicarbonates, probably as a mixture Alkali bicarbonate and alkali hydroxide are the same

Weight ratio before. It is appropriate to use alkylene oxides and water in a molecular ratio of 1: 1 to 1: 1.3, preferably 1: 1.1 to take.

The essence of the method according to the invention is shown in the scheme of the process given below the production of Ethyleuglycol illustrated

up to 120 ⁰ C

- »HIGH, —CH ₂ OH

CH,

CH, + H, O + CO,

I. ο

3?

up to 12O ⁰ C

-> CH ₂ -

O
\

-CH ₂
O

The reaction of ethylene oxide with carbon dioxide is faster than that with water, and it works Hydrolysis of the resulting intermediate product (ethylene carbonate) forms even at stoichiometric Water quantity practically only ethylene glycol.

From the above scheme it can be seen that in the production of alkylene glycols, carbon dioxide is not consumed, but allows the process to be carried out under the necessary conditions.

The claimed process for the production of alkylene glycols can either be discontinuous or continuous process can be realized.

In the batchwise procedure, alkylene oxide, water and catalyst are placed in a stirred autoclave a, after which carbon dioxide is added until a pressure of 10 to 30 atm is established in the autoclave.

The mixture obtained is ^{heated to 80 to 130 °} C. with constant stirring, the pressure initially increasing, then it begins to decrease when the temperature mentioned is maintained. After the drop in pressure has ceased, the temperature is increased to 180 to 220 ^° C. and held in this range until the pressure increase occurs. Thereafter, the pressure is reduced and the catalyst is subjected to vacuum rectification.

In addition, the batch process while maintaining a stable pressure in the Autoclave can be brought about.

The continuous process for the production of alkylene glycols can be carried out in two reactors connected in series. In the lower part of the first reactor, alkylene oxide, water, catalyst and carbon dioxide are passed, and from its upper part the reaction mixture enters the lower part of the second reactor. The temperature in the former reactor is 80 to 12O ⁰ C, in zweiteren -160 to 220 ° C. The pressure in the system makes at from 15 to 40. The carbon dioxide is circulated in the system by means of a circulating gas pump.

The continuous process can also be carried out in a reactor, preferably at at a temperature of 160 to 22O ⁰ C and a pressure of 20 to 60th

Both the batch process and the continuous process can be chosen from among the adiabatic Conditions to be carried out.

example 1

In a stirred autoclave with a capacity of 11, 180 g of ethylene oxide, 74 g of water, 2 g of tetramethylammonium iodide, Entered 1 g of sodium bicarbonate, then carbon dioxide is fed into the autoclave until the pressure reaches 30 atm.

The reaction mixture is heated to 100 ⁰ C, and the temperature gradually increased to 220 ⁰ C. At the end of the reaction, the pressure reaches 140 atm. After the pressure has been reduced, the catalyst is subjected to vacuum rectification, and 237 g of monoethylene glycol are obtained, which corresponds to a yield of 96 percent by weight of theory, calculated on ethylene oxide, and 7 g of diethylene glycol.

Example 2

Into a stirred autoclave of 1 I ₁ capacity 180 g of ethylene oxide, 74 g of water are added 1.5 g of tetraethylammonium bromide and then pumped carbon dioxide, at reaches * until the pressure in the autoclave 30th

The reaction mixture is ^{heated to 130 °} C. and this temperature is maintained for 25 minutes. The reaction mixture is then ^{heated to 200 to 220 °} C. and this temperature is kept constant until the pressure increase is established.

After the pressure reduction, the catalyst is subjected to vacuum rectification, and one obtains 223 g of monoethylene glycol, which is a yield of 89 percent by weight of theory, calculated on Ethylene oxide, and 16 g of diethylene glycol.

Example 3

In a stirred autoclave with a capacity of 1 liter

180 g of ethylene oxide, 40 g of water, 2 g of triethylamine hydroiodide entered and carbon dioxide pumped in until the pressure in the autoclave is 30 at achieved.

The reaction mixture is heated to 130 ° C and maintains this temperature while stirring for 35 mi

grooves. After adding 36 ml of 3% aqueous potassium bicarbonate solution, the reaction mixture becomes heated at 180 ° C for 40 minutes until the pressure increase.

After the pressure decrease, reaction products are subjected to vacuum rectification, and one obtains 240 g of monoethylene glycol, which is a yield of 97 percent by weight of theory, calculated on Ethylene oxide, and 2 g of diethylene glycol.

Example 4

In a stirred autoclave with a capacity of 1 liter, 180 g of ethylene oxide, 74 g of water and 2 g of propyiamine hydroiodide are placed and added 1 g of potassium bicarbonate.

The reaction mixture obtained is ^{heated at 130 °} C. for 30 minutes, a pressure of about 20 atm being kept constant in the system by continuously introducing carbon dioxide into the autoclave. Then the addition of carbon dioxide is stopped and the reaction mixture is heated at a temperature of 180 to 220 ° C. for 35 minutes. After the pressure has dropped, 254 g of catalyst are discharged and rectified in vacuo. 230 g of ethylene glycol are obtained, which corresponds to a yield of 92 percent by weight of theory, calculated on ethylene oxide, and 13 g of diethylene glycol.

B e i s ρ i e 1 5

174 g of propylene oxide, 56 g of water, 2 g of tetramethylammonium iodide, Entered 1 g of sodium bicarbonate and introduced carbon dioxide until the pressure in the autoclave reached 10 atm.

The reaction mixture is heated with stirring initially at 14O ⁰ C for 30 minutes and then at 200 ° C for 40 minutes. At the end of the experiment, the pressure reached 120 atm. After the pressure had been reduced, reaction products were subjected to vacuum rectification, and 213 g of propylene glycol, which corresponds to a yield of 93 percent by weight of theory, calculated on propylene oxide, and 10 g of dipropylene glycol were obtained.

B e i s ρ i e 1 6

150 g of 1-hexene oxide, 30 g of water and 2.5 g of diethylamine hydrochloride are placed in a stirred autoclave with a capacity of 1 liter and added 0.5 g of sodium carbonate.

The reaction mixture obtained is heated with stirring at 140 ° C for 30 minutes by im System maintained a pressure of about 30 atm by continuously feeding the carbon dioxide into the autoclave will. Then the supply of carbon dioxide is stopped and the reaction mixture is heated 180 to 220 ° C for one hour.

After the pressure has been reduced, the catalyst is subjected to a vacuum rectification.

The yield of monohexenglycol is 52 percent by weight of theory, calculated on 1-hexene oxide.

Example 7

In a stirred autoclave with a capacity of 1 1, 180 g of ethylene oxide, 74 g of water, 1 g of triethylamine, Entered 1.5 g of ethylene iodide and 1 g of sodium carbonate.

The reaction mixture obtained is at 120.degree heated for 30 minutes by a pressure of about 20 al in the system by continuous supply of the carbon dioxide in the autoclave. Then you stop adding carbon dioxide, and the reaction mixture is at 180 to 220 ° C during Heated for 40 minutes.

After the pressure has been reduced, reaction products are subjected to a vacuum rectification. Man receives 238 g of monoethylene glycol, which corresponds to a yield of 96 percent by weight of theory, calculated on Ethylehoxid, corresponds, and 6 g of diethylene glycol.

Example 8

The reaction is carried out in two reactors operated continuously and connected in a specific sequence. A mixture consisting of 81% ethylene oxide, 18% water, 1% tetraethylammonium iodide and carbon dioxide is introduced into the lower part of the first reactor. From the upper part of the first reactor, the reaction mixture enters the lower part of the second reactor, to which a 3% strength aqueous sodium bicarbonate solution is also fed. ^{A temperature of 120 °} C. is maintained in the first reactor, and a temperature of 200 ° C. in the second. The pressure in the system is 25 at. The carbon dioxide is circulated in the system via a circulating gas pump.

The volume rate of feeding the reaction mixture to the former reactor is 0.7 Percentage by volume per 1 volume of the reactor per hour. The volume rate of feeding the 3% aqueous sodium bicarbonate solution to the second reactor is 0.1 vol. Per 1 volume of the reactor per hour. The yield of ethylene glycol makes 96 percent by weight of theory, calculated on ethylene oxide, out.

Example 9

In a stirred autoclave with a capacity of 11 180 g of ethylene, 74 g of water and 2 g of potassium iodide are entered, after which carbon dioxide is introduced until the pressure reaches 30 to 35 atm.

The reaction mixture is heated to 130.degree and this temperature is held for 15 minutes; then the temperature increases to 200 bis 220 ° C increased and held for 2 hours. At the end of the experiment the pressure reaches 130 at.

After the pressure reduction, reaction products are subjected to vacuum rectification, and you receives 225 g of monoethylene glycol, which is a yield of 90 percent by weight of theory, calculated on Ethylene oxide, and 15 g diethylene glycol.

Example 10

In a stirred autoclave with a capacity of 11 174 g of propylene oxide, 56 g of water, 3 g of sodium iodide, 1 g of sodium bicarbonate are entered and Carbon dioxide passed until a pressure of 15 at, which is kept constant.

The reaction mixture is ^{heated to 120 °} C., then the temperature is increased to 180 to 200 ^° C. over 80 minutes.

After the pressure has been reduced, 214 g of catalyst are obtained discharged and subjected to vacuum rectification. The yield of monopropylene glycol is 95.5 Weight percent of theory based on propylene oxide.

Example 11

In a stirred autoclave with a capacity of 1 l, 180 g of ethylene oxide and 40 g of water are placed. 2 g of potassium bromide entered and carbon dioxide passed until a pressure of 30 atm is established in the autoclave.

The reaction mixture is heated at 12O ⁰ C for one hour, and after the addition of 35 ml of 3% aqueous potassium bicarbonate solution, it is heated at a temperature of 180 to 200 ° C for 40 minutes, until the pressure increase ceases. After the pressure has been reduced, the reaction mixture is discharged and subjected to vacuum rectification. 241 g of monoethylene glycol are obtained, which corresponds to a yield of 97 percent by weight of theory, calculated on ethylene oxide.

Example 12

180 g of ethylene oxide, 74 g of water, 0.7 g of lithium bromide, 0.4 g of caustic soda entered and carbon dioxide introduced until there is pressure in the autoclave of 50 at, which is kept constant.

The reaction mixture is at 120 ° C during 20 minutes, then heated at 200 ° C. for 40 minutes. After the pressure drop, the catalytic converter subjected to vacuum rectification, 227 g of monoethylene glycol, which gives a yield of 91 percent by weight of theory, calculated on ethylene oxide, and 16 g of diethylene glycol is obtained.

Example 13

174 g propylene oxide, 56 g water, 2 g potassium iodide, Entered 1 g of potassium bicarbonate and introduced carbon dioxide until there is pressure in the autoclave of 30 at which is kept constant.

The reaction mixture is at 120 ° C during 3 to 4 minutes, but then heated at 200 ° C for 80 minutes

After the pressure reduction, the catalyst is subjected to vacuum rectification, with 212 g Propylene glycol, which gives a yield of 93 percent by weight of theory, calculated on propylene oxide, corresponds to, and 11 g of dipropylene glycol is obtained.

Example 14

In a stirred autoclave with a capacity of 1 1, 180 g of ethylene oxide, 74 g of water, 2 g of ethylene iodohydrin, Entered 2 ^ g of potassium bicarbonate and introduced carbon dioxide until it is in the autoclave A pressure of 30 at is set which is kept constant.

The reaction mixture is first at 120 ° C for 30 minutes, then at 180 to 200 ° C during Heated for 40 minutes After the reaction has subsided, the pressure is reduced and the catalyst is reduced subjected to vacuum rectification. 236 g of monoethylene glycol are obtained, which is a yield of 95.3 percent by weight of theory, calculated on ethylene oxide, and 7 g of diethylene glycol.

Example 15

The manufacturing process of ethylene glycol is carried out under the adiabatic conditions

In a stirred autoclave with a capacity of 11 a thin-walled glass with thermal insulation is used and a sealed AmpuDe is inserted into it with one of 140 g of ethylene oxide, 74 g of water, made up to 1.6 g of sodium iodide and 1 g of sodium bicarbonate mixture. Then the autoclave Carbon dioxide fed until the pressure reached 20 at, the temperature increased to 120 ° C, after which the ampoule is broken by the agitator switched on.

Within 5 minutes, raising the temperature to 215 ⁰ C. takes place by the heat of reaction, the reaction mixture is maintained for i0 minutes at this temperature. The pressure in the system increases to 180 atm at the end of the experiment.

After the autoclave has cooled down and the pressure has been reduced, reaction products are discharged and subjected to vacuum rectification, 172 g of ethylene glycol and 11 g of diethylene glycol are obtained.

Example 16

The process is carried out in two continuously operated reactors installed one after the other.

A mixture consisting of 68.7% ethylene oxide, 29.7% water, 0.8% sodium iodide, 0.8% sodium bicarbonate, and separately supplied carbon dioxide is introduced into the lower part of the first reactor. From the upper part of the first reactor, the reaction mixture enters the lower part of the second reactor.
The temperature in the former reactor is 120 ⁰ C, in other ^ -200 ° C. The pressure in the system is 30 at.

The circulation of the carbon dioxide in the system is brought about by a circulation gas pump. The volume speed the feed of starting products into the former reactor is 0.3 volume per volume of the reactor per hour. The yield of ethylene glycol is 96 percent by weight of theory, calculated on ethylene oxide.

Example 17

174 g of propylene oxide, 56 g of water, Ig tripropylamine, 1 g of propyl bromide and 1 g of sodium carbonate are introduced into a stirred autoclave with a capacity of 1 liter. The reaction mixture obtained is heated at 140 ° C. for 10 minutes by maintaining a pressure of 40 atm in the system by continuously introducing carbon dioxide into the autoclave. Thereafter, the introduction of carbon dioxide is stopped, and the reaction mixture is ^{heated at 200 °} C. for 45 minutes

After the pressure reduction, the catalyst is subjected to vacuum rectification, with 216 g Propylene glycol, which gives a yield of 95.5 percent by weight of theory, calculated on propylene oxide, corresponds and receives 6 g of diproylene glycol

Example 18

180 g of ethylene oxide, 74 g of water, 2 g of propylene bromohydrin and 1.5 g of sodium carbonate are introduced into a stirred autoclave with a capacity of 11. The reaction mixture obtained is heated at 130 ° C. for 15 minutes by maintaining a pressure of 35 atm in the system by continuously introducing carbon dioxide into the autoclave heated to 190 ⁰ C until the pressure increase occurs

309 648/264

3633

ίο

After the pressure reduction, reaction products are subjected to vacuum rectification, whereby one 238 g of monoethylene glycol, which corresponds to a bulge of 96 percent by weight of theory, calculated on ethylene oxide, corresponds to, and receives 4 g of diethylene glycol.

Example 19

110 g of ethylene oxide, 58.5 g of water and 3.4 g of sodium chloride are placed in an autoclave with a volume of 0.55 l and 0.5 g sodium bicarbonate added. The mixture obtained is at a temperature of 130 ° C for a period of 52 minutes heated, the pressure in the system of about 30 atm due to the continuous addition of carbon dioxide is maintained in the autoclave. Then the addition of carbon dioxide is stopped and the reaction mixture is heated at a temperature of 200 ° C. for a period of 60 minutes. After Lowering the pressure, 172.2 g of the catalyst are removed and subjected to a vacuum rectification. 146 g of ethylene glycol are obtained, which is a yield

of 94 percent by weight of the theoretical converted to ethylene oxide and 4.0 g of diethylene glycol is equivalent to.

Example 20

100 g of ethylene oxide, 58.5 g of water, 3.4 g of potassium chloride and 0.5 g of sodium bicarbonate are placed in an autoclave with a volume of 0.55 l. The reaction mixture obtained is heated at a temperature of 130 ° C. for a period of 35 minutes, the pressure in the system of 30 atm being maintained by continuously introducing carbon dioxide into the autoclave. The introduction of carbon dioxide is then terminated and the reaction mixture is ^{heated at a temperature of 180 to 20O 0} CTU for a period of 60 minutes.

After the pressure has been reduced, the reaction products are subjected to a vacuum rectification. Man receives 147 g of monoethylene glycol, which is converted to 95 percent by weight of the theoretical yield corresponds to ethylene oxide and 3.0 g of diethylene glycol.

Table for examples 19 and 20

beginning Reaction rate ° C end time
(Min.) Pressure (ata) end catalyst ratio Yield ii Dialkylene
glycol 2 4th 5 7th Alkylene oxide ι weight II 130 time
(Min.) 200 60 beginning 30th 8th to water percent of theory 3.0 130 3 180-200 60 6th 30th NaCl 9 mono- 2.7 1 52 30th KCl 1: 1.3 , alkylene
glycol 19th 35 30th 1: 1.3 10 20th 94 95 ·

I. at the start Reaction temperature "C at the end 130 ° ° to 220 ^c 200-220 ' Duration
in min. On
catching
pressure Pressure, at catalyst Ver yield
the theory 9
Di-
alky-
len-
glycol at
game
No. 2 time
length of time
in
Min. 4th 5 6th Final pressure 8th ratio
Alkylene
oxide to
water in ° /
mono-
alkylene
glycol Il 1 3 gradual increase of 25 ' 30th 7th Tetramethylammo- 9 10 1.6 2 lOO 140 nium iodide. 1: 1.1 96 Sodium bicarbonate 130 " 180 = Heat up 30th Tetraethylammo- 3.7 for setting Pressure increase up to nium bromide I: 1.1 89 35 ' ment of Setting the 3 130 " 180-220 ^c pressure increase increase SO 40 " 30th Triethylamine hydro 0.5 4th 140 ° 200 ° Pressure increase up to iodide, sodium 1: 1.3 97 Setting the bicarbonate SO' 35 ' 20th increase Propylamine hydro ;.,O 5 140 ° 180-220 ° 20th iodide, potassium bicar 1: 1.0 92 bonat 30 ' 40 ' 10 Tetramethylammo- 1.9 6th 120 ° 180-220 ° 120 nium iodide, 1: 1.0 93 Sodium bicarbonate 30 ' 60 ' 30th hydrochloric acid diethyl 7th 120 ° 200 " 30th amine, sodium 1: 1.1 52 (in the 1st Re (in the 2nd Re carbonate actuator) 0.7 actuator) 40 ' 20th Triethylamine, ethyl 1.4 8th Sid. " ¹ 20th iodid and 1: 1.1 96 Sodium carbonate 0.8 - ' 25th Tetraethylammo- (Pressure throughout nium iodide. 1: 1.1 96 System: the reaction Sodium bicarbonate is in two conti naturally working Reactors through guided)

1 C

continuation

9 at the start action temperature X ' at the end Duration
in min. On-
catching
pressure Pressure, at catalyst Ver yield
the theory Ό
Tuesday
alkj
len
glyc at
game
No. IO 2 time
length of time
in
Min. 4th 5 ft Final pressure 8th ratio
Alkylene
oxide to
water in '/
mono-
alkylene
glycol Il 1 130 " 3 200-220 " 120 " 30-35 7th Potassium iodide 9 10 3 ,. Il 120 " 15 ' 180-200 " 80 ' 15 ' 130 Sodium iodide, 1: 1.1 90 80 ' 15th Sodium bicarbonate 1: 1.0 95.5 120 " 180-200 " 40 ' 30th Potassium bromide, 12th 60 ' Pressure increase up to Potassium bicarbonate 1: 1.3 97.0 Setting the 13th 120 ° 200 ° 40 '. 50 increase Lithium bromide, 3, " 20 ' 50 Caustic soda 1: 1.1 91.0 14th 120 ° 200 ° 80 '' 30th Potassium iodide, 2, C 30 ' 30th Potassium bicarbonate I: 1.0 93.0 15th 120 ° 180-200 ° 40 ' 30th Ethylene iodohydrin, l, ( 30 ' 30th Potassium bicarbonate 1: 1.1 95.3 16 120 ° 215 ° 10 ' 20th Sodium iodide, 2, i 5 ' 180 Sodium bicarbonate 1: 1.3 88.5 120 ° 200 " 0.8 30th Sodium iodide, (in I. Re 0.8 (in the 2nd Re Sid. " ¹ (Pressure in the system; the Sodium bicarbonate I: 1.1 96 actuator) Hour ¹ actuator) Reaction will come in two 17th continuously working tend reactors 140 ° 200 ° 45 ' 40 accomplished) Tripropylamine, 1, 18th 10 ' 40 Propyl bromide, 1: 1 95.5 Sodium carbonate 130 ° 180-190 " heat up 35 Propylene bromohydrin, O ₁ S 15 ' for setting Pressure increase up to Sodium carbonate I: 1.1 96 ment of Setting the pressure increase increase

Claims (1)

Patent claims: 1. A process for the preparation of alkylene glycols by catalytic hydration of alkylene oxides with heating, characterized in that the hydration of the alkylene oxides in the presence of carbon dioxide under a pressure of 10 to 180 at at a temperature of 80 to 220 ⁰ C using as a catalyst of alkali metal halides or compounds of the general formula