DE1668465A1 - Process for the preparation of alpha-alpha-dialkyl-ss-propiolactones - Google Patents

Description

W.Schalk dipl.-ing. P. Wirth dipl.-ing. G. Dannenberg

DR-V.SCHMIED-KOWARZIK DR. P. WEI NHOLD

6 FRANKFURT AM MAIN CR. ESCHENHEIMER STR. 39

SK / SK

MITSUBISHI Chemical Industries limited Ho. 2-4 Marunouchi, Ohiyoda-ku

Tokyo / Japan

Process for the production of ικ, αό -dialkyl-ß-

propiolactones

The present invention relates to an advantageous process for the preparation of ^, o ^ -dialkyl-ß-propiolactones, by a fvf, -X-dialkylpropionic acid with a halogen, a Hydroxy or an acyloxy radical on the ß-carbon atom in Subjecting the presence of a catalyst to a catalytic reaction .

It is known that ¹ X * _f & - -disubstituted β-propiolactones are easily polymerized in the presence of a suitable polymerization catalyst to form a polymer which is suitable as a raw material for synthetic fibers or synthetic resins. Known processes for the preparation of / <f, «'V-disubstituted β-propiolactones include, for example, the synthesis described in US Pat. No. 2,356,459, in which dimethyl ketone and formaldehyde are subjected to an addition reaction to form pivalolactone, as well as in German Patent No. 1,167,809 described method in which Monohalogenpivalinsäure reacted with a molar equivalent of a metal base in a solvent to form pivalolactone. From the economic

109831/2178 ' ² "

From this point of view, however, none of these known methods was satisfactory, since the pivalolactone was obtained in a purity that was too low in addition to its low yield, so dais in the subsequent one Purification to achieve the polymerization significant difficulties arise.

The aim of the present invention is therefore to create an improved process for the preparation of <x ', «vi-dialkyl-β-propiolactones without the above guard parts.

Another object of the present invention is to provide a process for the preparation of -v:, f - ^ - dialfcyl-β-propiolactones, in which a *> C, oc-dialkylpropionic acid with a halogen, a hydroxy or an acyloxy radical the ß-carbon atom in a liquid catalyst medium (reaction medium; ¹¹ "catalyst liquor)" containing a metal compound having catalytic activity, a catalytic reaction subjected ^r vird.

The present invention further provides a method for continuous production of V, ^ -dialkyl-ß-propiolactones with higher yield, which is carried out in a very simple manner.

The above objects are achieved by a process which is characterized in that a carboxylic acid of the general Pormel:

(1) . XGH ₀ -G-GOOH

R ₂

109831/2179 - 3 -

in which E ₁ and R _{2 represent} a lower alleyl radical and X represents a halogen atom, a hydroxy or an acyloxy radical 3, is subjected to a catalytic reaction with a catalyst medium containing a metal compound, whereby a compound

the formula:

(2) XH

in which X has the meaning given above, eliminated and

a ß-lactone of the following formula is obtained:

(3) R ₂ - C - C = O

CH ₂ -O

in which R ₁ and R _{2 have} the meaning given above.

This reaction can be represented by the following chemical equation will:

R ₁ Rj

XCH ₉ -C-COOH. r _ _c - C = O + XH * ■ ι ι

R ₂ CH ₂ -O

The use as starting material in the process according to the invention

one
The third carboxylic acid is / ß-substituted OL , eC-dialkylpropionic acid

the formula:

?1

XCH ₀ -C-COOH

in which R ₁ and R _{2 are} a lower alkyl radical, preferably a methyl or ethyl radical, and X is a halogen atom,

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denotes a hydroxy or a lower aliphatic acyloxy radical, where the halogen atom is chlorine or bromine and the acyloxy radical the formyloxy, acetoxy or propionoyloxy radical is preferred will.

Such ß-substituted <& , pC-dialkylpropionic acids include: oC ^ -dimethyl-ß-formyloxypropionic acid, ei , o (-diethyl-ß-formmyloxypropionic acid, d-methyl - ^ - ethyl-ß-acetoxypropionic acid, flU ^ -dimethyl -ß-acetoxypropionic acid, ö (, 0 (-Dimethyl-ß-propionoyloxypropionic acid, <^, fl (-diethyl-ß-propionoyloxypropionic acid, d ,, cC-dimethyl-ß-hydroxy propionic acid, (fi , dt-diethyl-ß- hydroxypropionic acid, ol-methyl - ^ - ethyl-ß-hydroxypropionic acid, (^ ,.? (- dimethyl-ß-chloropropionic acid, (^, ^ - diethyl-ß-chloropropionic acid, ot-methyl-it-ethyl-ß-chloropropionic acid, e (, o (-Dimethyl-ß-bromopropionic acid, o (, ö (, - I) ethyl-ß-bromopropionic acid and o (-methyl-o (-ethyl-ß-bromopropionic acid)

(liquid) The catalyst medium used in the process according to the invention serves to increase the reaction rate and to improve the selectivity of the formation of the ß-lactone. One such The catalyst medium contains a metal compound as a catalyst component from group I to VIII of the 3 Periodic Table.

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Such metals include lithium, sodium, potassium, copper, silver, Magnesium, calcium, barium, zinc, cadmium, mercury, boron, aluminum, thallium, titanium, zirconium, thorium, tin, lead, Vanadium, antimony, bismuth, chromium, molybdenum, uranium, manganese, iron, cobalt, nickel and palladium.

Although the compound of these metals shows different properties when used as a catalyst in the process of the present invention, the type of catalyst must be appropriately selected in consideration of the acid used as the starting material in the reaction and the reaction conditions. When using e ^^ - dialkyl-ß-acyloxypropionic acids as the starting material, the preferred compound is, for example, that of aluminum, lithium, vanadium, chromium, titanium, manganese or boron, due to the high reaction rate and excellent selectivity. When using d ^ (- dialkyl-ß-hydroxypropionic acids, the most effective compound is, for example, one of boron, lithium, barium, zirconium, tin, bismuth, manganese or cobalt, while when using o (, <i-dialkyl · ■ ß -halopropionic acids as a compound of lithium, zinc, tin, vanadium, bismuth, manganese, iron or nickel is preferred due to the good catalytic effectiveness and selectivity. Although it is expedient to use these metal elements in the form of a homogeneous solution of a solvent or a starting acid itself To use, they can also be used in the form of a suspension, in which they remain partially undissolved.To form a homogeneous, liquid phase for carrying out the reaction, the use of

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the following metal compounds are appropriate:

Organic acid salts of the metal elements, such as 2.B. the acetate, and basic salts thereof, inorganic acid salts such as the hydocide, carbonate, nitrate, oxides, hydrates of the oxide and Coordination compounds such as acetylacetonate. For example, the acetate gives difficulty in dissolving in organic solvents having a high boiling point, but is under special reaction conditions described below soluble.

Although the appropriate amount of catalyst contained in the catalyst medium varies depending on the effectiveness of the particular catalyst to be used, this amount can be determined in view of the fact that the reaction rate is proportional to the amount of catalyst and the solubility of the catalyst under the particular reaction conditions. The amount of catalyst used is usually between 0.01-1 Mol / l, preferably between 0.05-0.6 mol / l. Lower amounts of catalyst result in a reduced space / time yield ß-lactone, while larger amounts of catalyst cause precipitation of the Catalyst and violent foaming, which in turn creates serious difficulties for the reaction.

The preferred one for making the above catalyst medium Solvent has a high boiling point, but, as mentioned above, the starting acids are also used for this purpose can be. The ß-Laoton formed by the reaction

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is sensitive to the catalyst, so that prolonged contact of the ß-lactone with the catalyst medium is easy Accompanying reactions, such as the decomposition and polymerization of the β-lactone formed and the associated reduction in the reaction yield leads. Therefore, the β-lactone must be removed from the reaction system immediately after it is formed. To this Purpose, the reaction system is usually kept under boiling conditions in order to have the lowest concentration in the catalyst medium to maintain formed ß-lactone. For this purpose, the solvent used in the process according to the invention must expediently be a Can form catalyst system with liquid phase, which is essential according to the invention, while the reaction system in the keeps boiling state, thereby reducing the concentration of the formed to reduce ß-lactones in the catalyst medium.

To meet these requirements, the solvent must have a significantly lower vapor pressure than that formed β-lactone; it must continue to dissolve the catalyst well and easily, do not have an adverse effect on the reaction and be heat-resistant.

Such solvents are, for example, esters of benzene carboxylic acids such as dibutyl phthalate and dioctyl phthalate, aromatic phosphates, such as tricresyl phosphate, aromatic halogen compounds such as chlorinated diphenyl and aromatic ethers.

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Regardless of how the method according to the invention is carried out it is always advisable to remove the reaction products from the reaction system immediately to prevent side reactions of the ß-lactone formed can be avoided. It is believed,

the
that / ß-lactone first in the main reaction from the starting acid

formed and then branched into a subsequent reaction Olefin and gaseous carbon dioxide is broken down; this second reaction can be avoided by removing the ß-lactone removed from the reaction system immediately after its formation. ^ To do this, the pressure in the reaction system should be reduced or a inert gas are introduced, the type of catalyst and the applicable reaction conditions must be taken into account. In one embodiment of the present invention a reaction vessel containing a high boiling point solvent and a catalyst at a suitable temperature kept the reaction system under a correspondingly decreased Pressure is held; a starting acid is introduced into the reaction vessel at the appropriate rate, and at the same time the ß-lactone formed by the reaction and the by-products formed according to the starting acid, such as acetic acid, water or hydrogen halide, from the reactin system removed and collected by conventional means such as cooling, condensation or absorption. Then the collected Purified reaction distillate to pure ß-lactone.

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That obtained from the catalyst medium during the reaction Distillate consists mainly of ß-lactone, the by-products corresponding to the starting acid used, the starting acid itself, the solvent and gases. Starting acid and solvent are expedient by means of a dephlegmator or separated from the reaction products in a distillation column for recycling to the catalyst medium. The introduction an inert gas into the medium through the reactor bottom causes better agitation of the catalyst medium and an easier one Distillation of the ß-lactone formed. However, the amount of gas introduced into the reaction system should be limited so that a reduced pressure is maintained in the system.

A high concentration of the starting acid is preferably maintained in the catalyst medium. Usually the starting acid is introduced into the catalyst medium at such a rate that the acid feed is caused by the acid consumption, including that for the unreacted distillate, is compensated. The starting acid is by means of an or several nozzles at the bottom of the reactor introduced into the reaction vessel, poured into drops onto the upper surface of the catalyst medium or introduced into the catalyst medium simultaneously with the inert gas. Often the responsiveness is increased, when the starting acid is introduced into the catalyst medium through the reactor bottom.

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The reaction temperature used in the process according to the invention

The temperature is determined by the type of starting acid, the catalyst, the solvent for the reaction and the intended reaction pressure in the reaction zone. Usually, the reaction temperature is between · 100-35O ⁰ C, preferably between 150-30O ⁰ C. temperatures below 10O ⁰ C. result in a too slow reaction rate, while the increase in temperature above 300 ⁰ C. and 35O ⁰ C.
/ increased degradation, destruction of the solvent and

causes reduced service life of the catalytic converter.

As mentioned above, the reaction zone becomes for faster removal of the ß-lactone formed kept under reduced pressure. If the reaction takes place in a solvent / starting acid system in the boiling state under reduced pressure, a very low concentration of the ß- ^ actons is advantageous obtained in the catalyst medium. The reaction temperature and the type of solvent used can determine the determine reduced pressure, which is usually between about 0.1 to 500 mm Hg, preferably between about 10-200 mm Hg. The application of a pressure below 0.1 mm Hg not only gives a lower yield but also interferes with the collection of the reaction products, like ß-lactone and acetic acid. BeL an extremely reduced pressure, requiring the use of a solvent with a lower boiling point enables, wildly, the vapor pressure differential between solvent and i-lactone formed is reduced, so that the ß-lactone concentration in the catalyst medium increased and thus the yield is reduced.

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It is noted that the manner in which the invention is carried out is carried out The method is not limited to the above-mentioned manner using a batch reaction vessel; it can various reaction vessels including a thin film reactor can be used. That is, the inventive Process can be carried out batchwise or continuously.

As mentioned, the present invention provides an advantageous process for the production of ol, dt-dialkyl-ß-propionlacbons at higher Selectivity and with high yields. The appropriate choice of the solvent and the reaction conditions make it possible according to the invention, the process with respect to the formation xiea fl £, ct-dialkyl-ß-propionlactoiBund the recovery of the through by-products formed by the reaction from the starting acid practically to be carried out quantitatively. This was not the case with any of the known procedures the case.

In addition to the high yield of ano (, o (-dialkyl-ß-propiolactone gives the process according to the invention has a significantly improved space / time yield, which is from the economic, industrial point of view is crucial. For example, the production of pivalolactone is done at a rate of about 0.2 kg per liter of catalyst possible per hour if one ^, oi-dimethyl-ß-acetoxypropionic acid used as a starting acid under appropriate conditions. Also included are those used according to the invention Catalysts to the liquid phase catalysts, the effectiveness of which is not easily destroyed; However, if a

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If the catalyst efficiency decreases, part of the catalyst medium can pass through continuously during the reaction fresh catalyst medium must be replaced. By using this catalyst medium, according to the invention, the Heat of reaction easily supplied. When performing continuously of the method according to the invention will continue to be mainly ß-lactone and by-products are removed from the reaction system; therefore occur between these compounds and the catalyst no side reactions impairing the efficiency of the catalyst; and the purification of the reaction distillate is also easy.

The following examples illustrate the present invention, without restricting them.

Example 1_

A 2-1 four-necked flask was fitted with a dephlegmator, thermometer, capillary tube for introducing the gas and dropping funnel for introducing the starting acid. The dephlegmator consisted of a cylindrical distillation column which contained a central tube fitted with a reflux condenser. The toluene poured into this central tube was heated to reflux by means of the warm vapors rising through the column, so that a substance with a higher boiling point than toluene was returned to the flask . . .. The drip funnel with external heating means was attached so that its end reached to the bottom of the flask. The vapors emerging at the head of the dephlegmator were condensed by the cooler and taken up by a receptacle in the system kept under vacuum.

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In the flask described above, 500 g of dioctyl phthalate, 24 »7 g of chromium acetate monohydrate and 50 g of θί, ^ - dimethyl-ß-acetoxypropionic acid, hereinafter referred to as APA, were added and at a reduced pressure of 10-20 mm Hg to about 200 ⁰ G. heated. So the chromium acetate monohydrate was converted into the chromium salt of the starting acid, with practically the theoretical

from the amount of acetic acid and water / was distilled, which gave a catalyst medium in homogeneous phase. Under reduced pressure of 20 mm Hg, gaseous nitrogen at a velocity M is speed of 24 cc / min (relative to normal conditions) is introduced by dae capillary tube. Within 40 minutes, 112 g of molten APA were poured through the dropping funnel onto the bottom of the flask, the medium at a temperature of 230-235 ° C. was held. As a result of the vigorous boiling of the medium, acetic acid and the pivalolactone formed by the reaction were distilled off at the top of the ligmator, with the majority of the APA and solvent dissolving back to the reaction vessel.

. An analysis by gas chromatography of the after Reaction of collected distillate resulted in the formation of 44.6 g of pivalolactone. The quantitative determination of acetic acid and unreacted APA showed a 76% conversion and 86% selectivity for pivalolactone and about 100% Selectivity for acetic acid. Despite repeated use, no deterioration in the effectiveness of the catalyst medium was found.

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-H-

example

When trying to determine the catalytic effectiveness For various metal compounds, a similar but smaller device was used as in Example 1, which was a 200 cc flask contained. The results are shown in Table 1 below:

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Tabel

No catalyst

Catalytic Amount of reduced pressure reaction conversion amount in common acid in mm Hg time

Mole mole min $

selectivity

1
2
3

4th
5
6th

7th
8th

10
- * 11

* ° 13

- * 15
^ 16
κ) 17

-M 8
'19
20th
21
22nd
23
24
25th
26th
27
28
29
30th
31

(AA) =
(OAc) =

IiOAc

NaOAc

KOAc

Cu (AA) ₉

AgOAc

Mg (AA) ₅
Ca (AA) *

H, SbO, '
BI (OHf,
Cr (AA)
MoO (

Mn AA)
Fe OAc
Co OAc
Ni OAc j ρ
Pd OAc) 2

0.010 0.005 0.010 0.005 0.010 0.005 0.005 0.005 0.005 0.005 0.005 0.010 0.005 0.005 0.005 0.005 0.005 0.005 0.020 0.005 0.010 0.010 0.005 0.005 0.010 0.010 0.005 0.010 0.005 0.010 0.006

0.100 0.041 0.100 0.023 0.020 0.100 0.100 0.041

ο, on

0.041 0.048 0.100 0.100 0.035 0.025 0.100 0.100 0.100 0.087 0.100 0.060 0.100 0.100 0.073 0.031 0.100 0.100 0.66 * 1.26 * 2.33 * 0.45 *

20 60 20 50 50 50 50 60 60 60 50 20 50 50 50 20 20 20 40 20 20 20 50 50 20 20 50 20 20 20 20

90 60 30 90 60 90 110 60 60 60 90 15 90 80 80 10 20 120 120 70 90 40 90 80 40 70 50

15.9

12.5

53
34
82
78
• 1-0
76
54
57
51
91
59
60
22nd

18.8
64

9.4
70
41
51
62

72
7.5

93 40 41 90 92 53 57 50 35 37 70 62 96 67 98

5.4 18.8 22

29 92 32 36 94 79 29 85 50 27 29 12 95

the starting acid APA was carried out in a stream of nitrogen in Mbl / 1 catalyst medium per

introduced

Acetylacetonate

Acetoxy group

The catalyst media used in this example was prepared by mixing a given amount of catalyst and 1.1 times the amount of APA, calculated on the APA salt of the metal in the catalyst, admitted to 45 g of dioctyl phthalate and the resulting solution to about 200 ⁰ C. heated. The dephlegmator was filled with toluene, and nitrogen gas was introduced as a carrier gas at a rate of 24 cc / min (based on normal conditions) for a reaction at 240 ° C. The reaction was carried out in the manner described in Example 1.

Example 3

Using the reaction apparatus of Example 2, experiments were carried out with various solvents and varying reaction conditions made. With particular care, the solvent to be introduced into the central tube has been made easier Fractionation of pivalolactone and APA selected. The results are shown in Table 2 below, Solvent A is with chlorinated diphenyl, solvent B dibutyl phthalate and solvent 0 tricresyl phosphate.

Table 2

sol. React. vefm. Reäkt. sol.mitt. Conversion selectivity with. temp. Printing time in the dephleg

"C. mm Hg min. mator 57 r ¹ A. 240 80 50 Methyl carbitol 75 67 B. 220 50 60 toluene 82 71 G 250 3 50 benzene 98

The catalyst was prepared according to Example 2 from 0.010 mol of ohromacetate and 50 ecm of solvent. The reaction of 0.1 mole APA took place under the reaction conditions given in the table, with gaseous nitrogen at a rate of 24 cc / min (based on normal conditions) was introduced.

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Example 4

Using the reaction apparatus of Example 2, a catalyst medium was prepared according to Example 2 from 0.010 mol of chromium acetate and 50 g of dioctyl phthalate. 0.01 moles of APA were introduced into the catalyst medium within 40 minutes at 240 G and 20 mm Hg pressure, no nitrogen gas was introduced into the device, "the conversion was $ 82 and the selectivity to pivalolactone was $ 74. Upon introduction of gaseous nitrogen at a rate of 70 cc / min (based on normal conditions) conversion was $ 69 and

Selectivity 88 ° ß>.

Example 5

According to Example 2, using the device mentioned there, a catalyst medium for the conversion of 0.1 mol of APA was prepared from 0.0025 mol of chromium acetate and 50 g of dioctyl phthalate. The reaction took place at 240 ⁰ O and 20 mm Hg within 210 minutes. The conversion was $ 70 and the selectivity was about 100%. Were 0.005 moles of chromium acetate and 0.1 mol APA used and the reaction was conducted at 240 ⁰ G and 50 mm Hg within 50 minutes, the conversion i 69 °, and the selectivity was 91 #.

Example 6

Said apparatus there from 0.010 mol chromium acetate and 50 g of dioctyl phthalate in Example 2 v / urde using a catalyst prepared medium and 0.1 mol APA at 240 ⁰ O and 20 mm Hg pressure reacted within 50 minutes. The APA was introduced into the medium at the bottom of the reactor. The conversion was

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73 fi and the selectivity $ 84. If APA were poured in drops onto the surface of the catalyst medium, which took 60 minutes, the conversion was $ 82 and the selectivity was 92 %.

Example 7_

The reaction device consisted of a 200 cc four-necked flask, a fractionation column, a thermometer, a capillary tube for gas introduction and a dropping funnel for the starting acid. The fractionation column was a Widmer column 18 cm long. The top temperature of the column was set near the boiling point / under the reaction conditions ψβ3 pivalolactones ^ so that pivalolactan and acetic acid formed were distilled off. As a result, the components with a higher boiling point, ie the starting acid and the reaction solvent, were condensed for recycling to the flask.

In this apparatus 80 g Octachlortriphenyl were introduced with a boiling point of 500-55O ⁰ C. (as "Kanekuroro-C-SO" of Kanegafuchi Chemical Industries Ltd. Japan _r, commercially available) and 0.62 g of boric acid and 28O ⁰ C .heated. Gaseous nitrogen was introduced into this catalyst medium through the capillary tube at a rate of 24 cc / min (based on normal conditions). The reduced pressure was set to 10 mm Hg, the temperature being kept at 280 ^° C .; Within one hour, 10.6 g of molten APA was added to the flask through the dropping funnel. An analysis of the distillate by gas chromatography after the reaction has ended

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shows the formation of 6.06 g pivalolactone and 3.95 g acetic acid. The conversion was 100 #, the yields of pivalolactone and Acetic acid were quantitative.

Example 8

Using the reaction apparatus described in Example 7 80 g Hexachlordiphenyl were obtained with a boiling point of about 385-420 ⁰ C. (as "Kanekuroru-600" from Kanegafuchi Chemical Industries Ltd., Japan, commercially available) and 1.35 g of boric acid within 1.5 hours for reaction of 13.8 g APA at 270 ^° C. and 55 mm Hg pressure in the flask. The conversion was ™ 100 <fo, the yield of pivalolactone 97 #.

Example ^

Using the reaction apparatus described in Example 7 were 55 g of ^n-Kanekuroru C-80 "25 g Kanekuroru ^M-600" and 0.31 g of boric acid in the flask for reaction of 14.2 g APA at 275 ⁰ C. and 28 mm Hg pressure was introduced which would last 1.5 hours. The conversion was 100% and the yield of pivalolactone was 92%.

Example 10 Ä

The piston of the device according to Example 7 with 80 g Hexachlordiphenyl having a boiling point of about 385-420 ⁰ C. (as mentioned as "Kanekuroro-eoo" in the trade) and 1.24 g of boric acid and filled for the preparation of the catalyst medium to 27O ⁰ C. heated. Gaseous nitrogen was introduced into the medium through the capillary tube at a rate of 24 cc / min (based on normal conditions). Then, the pressure at 55 mm Hg was adjusted // was maintained obei the temperature to 270 ⁰ C.. A solution was added dropwise to the flask through the funnel over the course of one hour, which was obtained by dissolving 9.0 g

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ί ^^ - Dimethyl-ß-hydroxypropionic acid (hereinafter referred to as HPA) in 30 g of acetone. The distillate was collected at the top of the column and passed through when the reaction was complete Gas chromatography analyzed. It was 4.98 g of pivalolactone and the subsequent quantitative determination of the unreacted HPA showed a 66% yield of pivalolactone.

Example 1J_

Using the reaction apparatus described in Example 7 were placed in the flask 80 g "Kanekuroru-600" and 1, added 24 g of boric acid for the preparation of the catalyst medium at 250 ⁰ C.. According to Example 7, the reaction took place at 250.degree. and 30 mm Hg pressure by introducing an aqueous solution of 8.0 g HPA and 3.5 g water to the catalyst medium for 30 minutes. According to Example 1, reaction distillate and unconverted HPA were determined. The pivalolactone yield was $ 59.

Example 1_2

Using the reaction apparatus described in Example 7, 80 g of hexachlorodiphenyl (commercially available as "Kanekuroru-600" as mentioned) and 1.24 g of boric acid were introduced into the flask and heated to prepare the catalyst medium. The reaction was carried out according to Example 1 at ⁰ 29o C. and 120 mm Hg pressure by over 20 minutes, an aqueous solution of 6.0 g of HPA and 2.6 g of water was introduced into the catalyst medium. The pivalolactone yield was 57 % »

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Example 1_3_

Using the reaction device described in Example 7 with an IQO-cem flask, 40 g of pentachlorodiphenyl with a boiling point of 365-39O ⁰ G. (as "Kanekuroru-500" by
from Kanegafuchi Chemical Industries Ltd, Japan, commercially) and O ', 70 g boric anhydride and 9 »4 g HPA were added to the flask. The reaction was carried out at a temperature of 230-270 ⁰ C. and
a pressure of 100 mm Hg; pivalolactone was obtained with a conversion of 86% and a selectivity of $ 83.

Example 1_4

According to Example 13, various compounds were tested for
catalytic efficiency investigated. The results are shown in Table 3 below:

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Table 3

No. - » 1 Catalyst mol ), 005 Go.with. 4th ο
s> 2 LiOAc C H KC-500 η 3 ⁽ 3 Ba (OAc) _9, HoO It It tf NJ 4th Al ^ A CH ₂ j 2 C ^H 2/3 If Il It - » 5 Zr (AAj ₄ Il If 6th Sn (OAc) ₂ Il dd Il to 7th Bi (OH) ₃ Il Il ti 8th ISoO ₂ (AA) ₂ If Il Il 9 Mn (OAc) ₂ .4H ₂ O Il It Il 2φβ: Co (AA) ₂ —— It It AA ti OAc = Acetylacetonate «Acetoy group

HPA Reak.temp. Pressure reac. Yield Convert. Selectively. Mol ⁰ C. mm time <$>. <$><F ₀
Hg min

, 050 220-280 100 40 29 • ι Il Il 60 37 Il Il Il 80 25th It ti Il 80 31 Il 230-280 Il 60 35 Il It Il 60 44 It Il ti 50 22nd It It Il 50 38 It It •1 50 29 Il 210-270 H 60 ——

71 41 65 57 67 37 66 47 73 48 71 62 41 54 57 67 44 66

no reaction

CT, ι

As can be seen from Table 3, almost all compounds of metals in Groups I to VIII of the Periodic Table are used as catalysts effective.

Example Ij?

80 g of tetrachlorodiphenyl with a boiling point of 340-375 ° C. were placed in the flask of the device described in Example 7. (commercially available as "Kanekuroru-400" from Kanegafuchi Chemical Industries Ltd, Japan) and 0.66 g of lithium acetate and ^{heated to 210 °} C. to produce the catalyst medium. Gaseous nitrogen was introduced into the catalyst medium through the gas inlet pipe at a rate of 24 cc / min under a reduced pressure of 120 mm Hg; within 3 hours were 27.3 gV, ^ - dimethyl-.beta.-chloropropionic acid (hereinafter referred to as CPA) through a funnel at a temperature of 210-260 ⁰ C. to the flask dropwise. Analysis of the distillate by gas chromatography after the reaction had ended showed the formation of 14.2 g of pivalolactone. 6.00 grams of unreacted CPA was recovered. The conversion was 78% and the selectivity was 91%. The absorption of the gases by an aqueous sodium hydroxide solution confirmed the quantitative formation of sodium chloride <

Example 1_6_

According to Example 15, the catalyst properties became various Metal compounds examined; the results are shown in Table 4 below:

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catalyst OAc) ₉ -H ₉ O> Mole Solve with. G CPA Tabel 4th React. Convert. selectivity Verse. OAc) «. 4 EvO δ Mole Reak, - Druak Time i ° i ° No. AA) ₂ ^{2 l} temp. ΤΠΤΠ min LiOAc 0H),. 2H _o 0 0.010 KC-600 80 0.028 C. Ed 120 11 99 1* It / Ti (AATy ₉ ^ TiCl ₆ Il η 11 0 * 066 250 55 90 79 91 2 * LiCl Th (AA). ⁵ ^ * It KC-400 It 0.100 200-260 80 270 66 97 3 * KOAc Sn (OAoJo ti 11 ti 0.044 210-240 80 90 42 93 4 * Cu Pb (OAc) ₉ .3H ₉ O 0.005 Il 40 0.051 200-250 100 90 13th 85 VJl Mg VO (AA) ₉ ^ά 0.010 It 80 0.051 210-260 120 90 20th 95 6 * Zn Bi (OH); 0.005 ti 40 0.100 200-240 80 120 64 72 1 Al Cr (OAc? ,, H ₉ O
MoO ₉ (AA) ₉ ^c
Mn (OAc) _o T4H _o 0 N dd ti 0.100 210-260 120 150 36 86 θ Fe (AA), / ^d : 0.003 ti ti 0.100 210-260 120 180 8.9 79 9 Ni (OAc) ₉ '0.005 ti ti 0.044 210-250 120-250 120 15th 67 10 Vergieichsversüch It dd It 0.100 210-260 120-300 130 59 91 11 (O It ti ti 0.029 210-260 120 120 35 69 12th 00 1t ti Il 0.100 210-250 120-250 100 63 79 13th 1/21
ORIG ti Il It 0.100 210-260 120 HO ■ 67 90 14th 2 - «a It 11 Il 0.100 ti 11 60 36 42 15th 9
AL INSPECTED 11 It dd 0.069 Il Il 140 34 74 16 It ti Il 0.100 ti dd 90 58 88 17th dd dd Il 0.100 Il ti 100 61 74 18th 11 dd It 0.069 It dd 140 65 97 19th —— n It 0.050 It dd 120 no reaction It 120-400

In Table 4- above, (AA) represents acetylacetonate and (OAc) represents acetoxy group. "KC-400" stands for tetrachlorodiphenyl with an Έ. of 340-375 ⁰ O. and " ¹¹ KC-600" for hexachlorodiphenyl with an F. of 385-420 ⁰ C. (both from Kanegafuchi Chemical Industries ltd, Japan, in the ^{hands of} 1). Those marked with "*" Experiments were carried out in a 200 cc flask, the other experiments in a 100 cc flask.

From the above data it can be seen that compounds of almost all metals were effective in the reaction. Furthermore, since hydrogen halide was recovered quantitatively and the metal halide was effective as a catalyst, it can be concluded with certainty that the metal compound added to the reaction system did not act as a halogen acceptor from the starting acid. Comparison attempt

The reaction took place without a catalyst. 45 g of dioctyl phthalate was placed in a vacuum distiller equipped with a 100 cc flask. At a temperature of 27O ⁰ C. and a pressure of 60 mm Hg, gaseous nitrogen at a rate of 3 cc / min was introduced by the liquid bottom material in the device was "caused during the reaction by introduction of 6.6 g of APA, which took 40 minutes Analysis of the reaction distillate by gas chromatography showed only the formation of 0.10 g of pivalolactone and 0.15 g of acetic acid.

10j> 3'h / 2 179

Claims (12)

P a t e η t ans ρ r ü ο h e 1.- Process for the preparation of ß-lactones of the general Formula: (1) R ₀ - C - C = 0 CH ₂ -O in which R .. and Rp stand for a lower alkyl group, thereby characterized in that one has a carboxylic acid of the general formulaϊ (2) XCH _9-0 -COOH ^R 2. in which R ₁ and R _{2 have} the above meaning and X stands for a halogen atom, a hydroxyl or a low-aliphatic acyloxy group, is reacted in a liquid reaction medium which contains at least one metal compound as a catalyst to form a compound of the formula: (5) HX in which X has the above meaning to split off, 2.- The method according to claim 1, characterized in that an acid (2) is used in which R ₁ and R _{2 are} each methyl or ethyl and X is chlorine, bromine, hydroxy, formyloxy, acetoxy or propionoyloxy . 3.- The method according to claim 1 and 2, characterized in that the reaction at a temperature of 100-350 ° C. under reduced Pressure is carried out, preferably at the boiling point of the reaction mixture. 10 9831/2179 4.- Procedure nr-ch claim. 1 to 3, characterized in that an organic or inorganic salt, an oxide, oxide hydrate
or a coordination compound of a metal of the groups
1 to VIII of the periodic table used as a catalyst
will. " 5, - Method according to claim 1 to 4, characterized in that a high-boiling organic, inert solvent as the reaction medium is used, 6, - Method according to claims 1 to 5 *, characterized in that ß-Acetoxy-, ß-Hydroxy- or ß-Ohlorpivalonic acid as starting ™ material is used. 7 · - Process according to claims 1 to 6, characterized in that the metal compound in the reaction medium in a concentration
from 0.01 to 1 mol / l is used. 8.- The method according to claim 1 to 7, characterized in that a pressure of 0.1 - 500 KiHg is applied. 9.- The method according to claim 1 to 8, characterized in that the acid (2) is fed continuously to the boiling reaction medium under reduced pressure, an inert gas, preferably nitrogen, being introduced into the reaction medium
is, and at the same time the desired β-lactone and the resulting compound (3) of the formula HX are continuously withdrawn. 109831/2179 10.- The method according to claim 1 to 9, characterized in that ß-acetoxypivalic acid is continuously introduced into a reaction medium containing a compound of aluminum ^ lithium, vanadium, chromium :, titanium, manganese and / or boron in a concentration of 0, contains from 05 to 0.2 mole / 1 and held at a temperature of 180-270 ⁰ C., at a pressure of 10-200 mm Hg to boiling, at the same time, nitrogen is also introduced, and at the same time the vapors of pivalolactone and acetic acid, as they are formed, can be deducted. 11. The method according to claim 1 to 10, characterized in that ß-Hydrpxypivalinsäure continuously introduced into a reaction medium containing a compound of lithium, boron, zirconium ^ tin, bismuth, manganese, cobalt and / or barium in a concentration of 0 , / l containing 05 to 0.6 mol and ggialten at a temperature of 200-500 ⁰ C., at a pressure of 10-200 mm Hg to boiling, at the same time, nitrogen is also introduced, and at the same time the vapors of water and pivalolactone as they are formed, deducted. 12.- The method according to claim 1 to 10, characterized in that ß-chloropivalic acid is continuously in a reaction medium introduces a compound of lithium, zinc, tin, vanadium, Contains bismuth, manganese, iron and / or nickel in a concentration of 0.05-0.6 mol / l and at a temperature from 150-3OO ° C. kept boiling at a pressure of 1-500 mm Hg is, at the same time nitrogen is introduced, and at the same time the vapors of pivalolactone and hydrogen chloride, so, how they are formed, deducted. he patent attorney: 109831/2179