DE2112705A1 - Methods for preventing conjugated dienes from polymerizing - Google Patents

Description

JAPAN SYNTHETIC RUBBER COMPANY LIMITED, 1, Kyobashi, 1-chome, Chuo-ku, Tokyo, Japan

Methods for preventing conjugated dienes from polymerizing

The invention relates to a method for preventing polymerization conjugated dienes and, in particular, a method for preventing the polymerization of conjugated dienes in organic ones Solvents at relatively high temperatures.

Processes for extractive distillation or absorption by solvents for separating and refining butadiene or isoprene in high yield have become known, these two products being valuable materials or of C ₄ hydrocarbon fractions from split heavy oil, butadiene, butane, butylene and Contains isobutylene as main constituents, or of C, - hydrocarbon fraction which contains pentane, pentene, isoprene and piperylene as main constituents.

It is also known that solvents, such as acetonitrile (ACN), N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimthylacetamide (DMAC) and furfural can be used.

usually is of the conjugated dienes noted above known that they are easily oxidized at normal temperature by means of oxygen or the like, which is present in the solvents and tend to form polymers on prolonged standing. When separating or refining by means of conventional ones Extractive distillation or absorption processes make a solvent-containing butadiene or isoprene unavoidable Temperatures above the boiling point of the C. or Cg hydrocarbon fractions, e.g. subjected to over 70 ° C. As a result, there will be polymerization of butadiene or isoprene in the solvent accelerated and deposited the polymerization product. This

109842/1956 - 2 -

Phenomenon can easily be observed that the original clear solution discolored over time until it is translucent and shows deposits of the polymer.

Such polymer deposition creates numerous difficulties. For example, a thin polymer film is formed over the inner wall of the equipment, the outlets become plugged and the extraction efficiency is reduced, and thus it becomes difficult to work continuously for several hours.

It is an object of the present invention to overcome the difficulties described above, i.e., polymerization of the conjugated dienes during the above process steps to prevent.

In order to solve this problem, various investigations are necessary been employed and it has now been found that the polymerization conjugated dienes effectively through the addition of an organic one Phosphoric acid ester can be prevented, which is defined as follows will:

^R l O

S ₀ -OPO

* I

^R 3

Pyridine, quinoline, anthracene, - a compound with an alkyl group in the core substituent of the pyridine bucket compound with an alkyl group in the core substituent of the cainoline, etc. to a solvent such as ACN, NMP, DMF or BMAC in order to Extraction of the conjugated diene.

According to the invention, a method is thus created pull avoidance the polymerization of conjugated dienes in solvents at high temperatures, which is characterized by the addition of at least a compound selected from the class consisting of organic phosphoric acid esters of the general formula

109842/1956

■ "" 3 ■■ *

O
R_ - O - P = O

^R 3
where R ₁ , R 2 and R _{3 are} phenyl or ring-substituted phenyl groups

represent, where the substituents are alkyl groups, phenyl groups or halogen atoms, alkyl or halogenated alkyl groups or allyl groups, of pyridine, ring-substituted derivatives of pyridine, where the substituents are alkyl groups, quinoline, ring-substituted derivatives of quinoline, where A are the substituents alkyl groups, and Anthracene to a solvent containing conjugated diene.

Among the organic phosphoric acid esters, those according to the invention are more advantageous Ways can be applied include compounds such as triphenyl phosphate or ring-substituted derivatives the same, where the substituents are alkyl groups, phenyl groups or halogen atoms, trialkyl phosphates with or without Substitution of the hydrogen atom by means of the alkyl group Halogen atom, allyl biphenyl phosphate, diallyl phenyl phosphate and further compounds containing pehynyl groups or allyl groups.

Suitable triphenyl phosphate or ring-substituted products of the- ^ The same are triphenyl phosphate, tri- (o-cresyl) phosphate, tri (m- ~ kresyl) phosphate, tri (p-cresyl phosphate, trixylenyl phosphate, Tris (4-tert-butylphenyl) phosphate, tris (o-biphenyIyI) phosphate etc., wherein the substituents represent alkyl groups, phenyl groups or halogen atoms.

Suitable trialkylphesphates and halogen-substituted derivatives

O of these are trimethyl phosphate, triethyl phosphate, tri-n-propyl-

Φ phosphate, tri-iso-propy! Phosphate, ¥ ri-n-butyl phosphate, tri-sec. (fi ester, where the alkyl groups have 1 to 8 carbon atoms;

O ^ and tri (2-chloroethyl) phosphate, tri (2-bromoethyl) phosphate, tri (3-chloroporpoyl) phosphate, (Tri- (3-bromopropyl) phosphate, tri (3-iodopropyl) phosphate, Tri (2,3-dichloropropyl) phosphate - 4 -

Tri (2,3-dibromopropyl) phesphate, tri (2,3-diiodopropyl) phosphate, Tri (4-chlorobutyl) phosphate, tri (4-bromobutyl) phosphate, tri (4-iodobutyl) phosphate and further organic phosphonic acid esters containing halogen atom-substituted alkyl groups. As organic PhosphoBic acid esters that contain phenyl and allyl groups are Diallyl phenyl phosphate and allyl biphenyl phosphate are expedient.

Examples of compounds which represent alkyl groups in the core substituent of the pyridine are: picolines, such as 2-methylpyridine, 3-methylpyridine, and 4-methylpyridine; Lutidines such as 2,3-dimethylpyridine, 2,4-dimethylpyridine _r 2-ethylpyridine and 3 ethylpyridine; Collidines, such as 2-methyl-4-ethylpyridine, φ 2-methyl-5-ethylpyridine, 2-bropylpyridine, 2-isopropylpyridine and 2,4,5-trimethylpyridine; and parvolins such as 2,3,4,5-tetramethylpyridine and 2-butylpyridine. Examples of compounds whose alkyl groups are substituted in the nucleus of the quinoline are: alkylquinolines such as 2-methylehinoline, 3-methylquinoline, 2,3-dimethylquinoline , 3,4-dimethylquinoline, 2-ethylquinoline and 4-ethylquinoline.

These polymerization inhibitors can either be used to prevent the polymerization of conjugated dienes at high temperatures or are used for chain transfer of the polymerization, preventing the generation of any solvent-insoluble polymer. The obgn specified phosphorus m. Säureester have particularly good Polymerisationsinhibierungs effect.

These polymerization inhibitors prove to be very effective, when they are applied individually. The effect of preventing the polymerization of conjugated dienes that is achieved by adding these compounds according to the invention, is however substantially increased when the compounds in combination with a larger number of compounds, e.g. sodium nitrate, potassium nitrate, sodium sulfide, phenolic compounds and aromatic amine compounds commonly used as polymerization inhibitors or antioxidants for unsaturated compounds find application. This comes true from the fact that the polymerization inhibitors can be classified into two "kinds from the point of view of their mechanism, i. e.

109842/1956 _ ₅ _

Free radical reaction inhibitor and peroxide decomposer and is contemplated to be related to polymer manufacture is based on the two-stage radical initiation and radical growth. The method according to the invention thus makes it possible to achieve the effect preventing conjugated dene from polymerizing in one ! It is remarkable to prevent solvents at elevated temperatures taking advantage of the synergistic effect of the two substances, which have different polymerization inhibiting abilities own. The combined use of different inhibitors is found to be particularly effective in preventing polymerization of isoprene.

The known polymerization inhibitors or antioxidants for A- unsaturated compounds which are used in combination with the inhibitors according to the invention are: ¹ ^ l) NaNO ₂ , KNO_, Na "S, methylene blue and mercaptobenzothiazole; (2) Phenolic compounds, for example hydroquinone, such as 2,5-di-tert.-butylhyroquinone and 2,5-di-tert.-amyroquinone, phenols, such as o-phenylphenol, 2,6-di-tert.-butyl -p-phenylphenol, butylated hydroxytoluene and p-methoxyphenol? Cresols, such as 2,6-di-tert-butyl-p-cresol, catechins, such as di-tert-butylcatechol and p-tert-butylcatechol, bisphenols, such as 2,2'-methylenebis (4-methyl-6 -tert-butylphenol) and 4,4'-methylenebis (2,6-di-tert-butylphenol); Naphthols, such as alpha-naphthol, β-naphthol, l, l'-methylenebis-2-naphthol; and aminophenols such as p-aminophenol and 2,6-di-tert-butyl-alpha-dimethyleneamine-pcresol and

$ 3) Aromatic amine compounds, e.g. ρ, ρ'-diaminodiphenylmethane, N-phenyl-alpha-naphthylamine, N-phenyl-ß-naphthylamine, p-isopropoxydiphenylamine, 4,4 "-Dimethoxydiphenylamine, N, N'-Dipheny1-p-phenylenediamine, Ν, Ν'-diphenylethylenediamine, Ν, Ν'-di-o-tolylethylenediamine, Ν, Ν'-naphthylenediamine, octy! Diphenylamine (mono- and di-) and 2,4-diaminotoluene.

According to the present invention, the effect of preventing the polymerization becomes of butadiene and isoprene is sufficiently achieved even in the presence of iron rust, which is generally believed to be too polymerisation of dienes. This eliminates the need to use expensive special steels as finishing material and continuous operation is possible via an

109 * 42/1958 " ⁶ "

- O "~

to maintain an extended period of time.

The amounts of the polymerization inhibitors to be added can be in accordance with the kind and the water content of the solvent and the applied operating conditions can be changed. Usually, however, the purpose is achieved by adding first of inhibitors, e.g. organic phosphoric acid ester, pyridine Quinoline, anthracene, the nuclear-substituted derivatives of pyridine and quinoline etc. in an amount of 0.01 to 10%, preferably 0.05 to 5% by weight based on the weight basis of the solvent, and then adding the second inhibitors, e.g. sodium nitrite, Phenol compounds, aromatic amine compounds, etc. in in an amount from 0.001 to 5%, preferably 0.005 to 1%, based on the weight basis of the solvent.

These inhibitors classified according to the above two groups can be added individually or in combination to the to achieve the desired effect.

It is of course understood that the amounts of these additives are not limited by the scope of the invention.

The invention is explained in more detail using exemplary embodiments.

example 1

70 parts of dimethylformamide, which contain 5% by weight of water, and 30 parts of butadiene are mixed and, after the addition of the following inhibitors, the mixtures are heated for 70 hours to a temperature of 150 ^° C. and under a pressure of 5.0 kg / cm reacted with iron oxide. The product conditions are then checked. Masses that are anhydrous are converted under the same conditions. The results are shown in Table I.

Example 2

Using the same conditions as described in Example 1 with the exception that acetonitrile as the solvent is applied, test solutions are prepared. The masses are given with different, in Table II Inhibitors reacted with heating to a temperature of 120 ° C for 70 hours in the presence of iron oxide. The results can be found in Table II.

109842/1956 - 7 -

Table I.

No. Polymerization inhibitor! .Inhibitors (wt.%) 2.Inhibitors (ppm) State after the
Heat conversion

Polymer content Weight%

1 no

2 "

3 triphenyl phosphate 0.5

4 "0.5

5 triphenyl phosphate 0.5

6 "0.5

7 "0.5

8 "1.0

9 Tricresyl Phosphate 1.0

10 "0.5

11 di-n-butylphosphateO, 5

12 tri (n-buty! Phosphate 1.0

13 Tris (4-tert-butylphenyl) 0.5

14 Tris (o-biphenylyl) phosphate 0.5

15 diallyl phenyl phosphate 0.5

16 tri-n-butyl phosphate 1.0

17 tricresylphesphate 0.5

18 ^Ί

no natriuronitrite

no

Sodium nitrite potassium nitrite sodium sulfide p-tert-butyl catechol phenyl-ß-

naphthylamine no

Sodium nitrite "

no

Sodium nitrite

Sodium nitrite

Sodium nitrite

p-tert-butylcatechol sodium nitrite

Sodium nitrite

19 ^ y triphenyl phosphate 0.5 sodium nitrite 20 tricresyl phosphate 0.5 sodium nitrite

Solvent (dimethylformamide) completely anhydrous,

100 100 100 polymer deposited 8.0

becomes slightly white 2.2

Il Il Il 17

clear 0.3

clear 0.5

clear 0.8

clear 1.0

clear 1.2

clear 0.5

clear 0.4

clear 0.7

clear 0.8

clear 0.3

clear 1.0

clear 1.2

clear 0.2

clear 0.8

Polymer deposited 6.3 clear 0.8

clear 1.0

Pv) CD

Table II

No. Polymerization inhibitor 1st inhibitors% by weight 2nd inhibitors

ppm State according to the polymer content 12.0 'I. becomes light and poly * -
mer is deposited 1.9
0.9
0.3 00
I. 100
100 becomes, borrows bright
clear
clear 0.7
1.1 200 clear
slightly yellowish 0.1
0.2 100
50 clear
clear 0, * 50 clear

no

no

no sodium nitrite

Tricresyl phosphate 1.0 none

¹¹ 0.5 sodium nitrite

Tri-n-butyl phosphate 1.0 none

"0.5 p-tert-butyl ca-

techin

"0.5 sodium nitrite

Triphenyl phosphate 0.5 "tri (2-chlororathyl) phosphate 0.5 "

Further experiments are carried out under the same conditions as described above with the exception that the Solvent acetonitrile by N-methylpyrrolidone or dimethylaceta amide is replaced. In either case, the addition of only sodium nitrite (100 ppm) results in the deposition of the polymer in 70 hours. Such polymer deposition does not occur and the solution remains clear when combined with sodium nitrite (100 ppm) Tricresyl phosphate (0.5 wt.%) Is added.

Example 3

There are 70 parts of acetonitrile containing 5% by weight of water with a C. hydrocarbon fraction of that shown in Table III given composition mixed. Each of the mixtures obtained is in the presence of different inhibitors for 70 hours of iron oxide in a hermetically sealed vessel at a temperature of 120 C under a pressure of 5 kg / cm heat converted. The results are given in Table IV.

Table III

Ingredient content (wt.% )

All 0.002

Methyl acetylene 0.019

Isobutane 2.605

Isobutene 32,755 (

1-butene 22.096

1,3-butadiene 33,847

η-butane1 2.400

trans -2-butene 4.541

cis-2-butene 1.690

Vinyl acetylene 0.041

Ethyl acetylene 0.003

1,2-butadiene 0.001

100,000

- 10 -

10 984271956

Table IV

No. Polymerization inhibitor! .Inhibitors wt.% 2.Inhibitors ppm

State according to polymer the heat content support weight%

1 no 0.5 no 100 Poylmer stores
himself off 10.6 2
3 no
no 0.5 slightly
v / eiss
v / ird white 4.2
7.3 4th Triphenyl
phosphate 0.5 Sodium nitrite 100
p-tert-buty1-
catechin 100 100 becomes minor
White 1.5 5 Il 1.0 no 100 clear 1.0 6th Tricresylphosphate
phat 1.0 100 clear 0.2 7th Tri-n-butyl
phosphate 1.0 p-tert-butyl-100
catechin clear 0.7 8th Pyridine 1.0 Sodium nitrite clear 0.5 9 Quinoline no clear 1.2 10 Anthracene Sodium nitrite clear 0.5 Il Il Example 4

80 parts of acetonitrile containing 5% by weight of water and 20 parts of butadiene are introduced into a hermetically sealed vessel. The mixtures obtained are treated with various inhibitors under heat for 70 hours in the presence of iron oxide at one temperature of 120 C and a pressure of 5 kg / cm. The results are shown in Table V below.

- 11 -

109842/1956

Table V

No. Polymerization inhibitor
1. Inhibitors% by weight. 2. Inhibitors 0.5 kin ppm 200 100 100 State after
Heat conversion Polymer content
Weight% 1 no 0.5 Sodium nitrite p-tert-butyl catechol 200 100 becomes white polymer
deposit 10.4 2 no IrO 200 Sodium nitrite 100 becomes slightly white 3.2 3 no 1.0 p-tert-butyl catechol 200 H 100 Il Il Il 4.1 4th Pyridine IfQ no no p-tert. ~ butyl catechol 200 Il H Il 2.2 5 Il 0.5 Sodium nitrite Sodium nitrided Sodium nitrite clear 0.7 O 6th Il 0.5 no Il 0.8 (O
00 7th alpha picoline 1.0 Sodium nitrite Il 0.5 •IN
KJ 8th 2-methyl-5-ethyl
pyridine 1/0 π 0.4 to 9 Chlnoline 0.5 pretty white 1.7 tn 10 Il 1.0 clear 0.1 11th Il clear 0.4 12th 2-methylquinone clear 0.8 13th Anthracene becomes slightly white 1.5 14th It clear IfO

Experiments are carried out under the same conditions as described above, with the exception that the acetonitrile solvent is replaced by DMF ₁ NMP or DMAC. In each case the addition of IOO ppm sodium nitrite alone leads to a whitening of the solution in 70 hours ^ while applying only Fyridin, ChinÖl £ n barren Anthraeen (0 _f 5 wt.% I the solution up 70 hours later clear häfct * The The transparency of the solution is maintained for even longer periods of time by the combined application of 100 ppm of matrilimitrite and one of the inhibitors.

The results of Examples I to 4 _r as given above »show the effect achieved in accordance with the invention for preventing the polymerization of butadiene at elevated temperatures *

Example 5

There are 70 files 5 wt.% Acetonitrile containing water and 30 Share isoprene with one or more of the listed below inhibitors mixed and the mixtures obtained are at 120 ° G implemented in the presence of iron oxide. The properties of the products are tested and the results are summarized in Table VI *

Table-ϊνΐ No.

Polymerization inhibitor
!. Inhibitors wt.% 2. inhibitors ppm

State after

Heating 24 h 80 h

no

4 "

5 triphenyl phosphate 0.5

6 "0.5

7 "0.5

no
Sodium nitrates 100

p-tert-butyl-100 kateehin

Phenyl-ß-naph-100 thyiamine

no

Sodium Nitrite 100 "50

Polymer is deposited

will be slight. Polymer white deposit

Polymer deposition

Polymer deposition

slight white polymer deposit clear clear

clear

slight White

109842/1956

- 13 -

ORIGINAL INSPECTS ©

No polymerization inhibitor state after

1 inhibitors% by weight 2nd inhibitors ppm heating

24 h 80 h

8 triphenyl phosphate 0.5 p-tert-butyl-100 clear slightly

catechin white

9 "1.0 phenyl-ß-naph- 100 clear"

thyIamin

10 tricresyl phosphate 0.5 sodium nitrate 100 clear clear

11 Tris (4-tert-bu-0.5 "100 ty! Phenyl) phosphate

Il Il

12 tri (n) butyl phosphate0.5 "100

13 Tris (o-biphenyl) - 0.5 "100 phosphate

14 diallylphenylphos-0.5 "100" " phat

Example 6

In an extraction-distillation column with 100-stage plates a Cg hydrocarbon fraction containing isoprene was introduced using an extraction solvent which is by means of additive of 0.5% by weight triphenyl phosphate and 100 ppm sodium nitrite to acetonitrile, which contains 5% by weight water, at a value (molar ratio) of 7: 1 of the Cc-hydrogen plank fraction has been produced. The mixture is continuously fed into the tenth stage of the column head and the column is operated at a reflux ratio of 5.0, a column top temperature of 47 ° C and a column bottom temper a door operated at 100 ° C. The isoprene-containing extraction solution is continuously reacted at the next stripping zone and the recovered extraction solvent is used directly returned to the extraction distillation column.

Operation continues for a week, but the extraction solvent shows no changes and remains clear. When repeating the same operation, however, without adding triphenyl phosphate and sodium nitrite to the solvent, the solution starts to turn white and becomes cloudy in 10 hours, resulting in a Polymer deposition that turns a light orange color in 20 hours.

109842/1956 " ¹⁴ "

Example 7

There are test solutions under the same as in Example 5— ■ conditions described with the exception that N-methylpyrrolidone as a solvent, as well as those below specified different inhibitors are used. The corresponding solutions are made in the presence of iron oxide reacted with heating to 140 ° C. The properties of the solutions are examined and the results are in the following table VII reproduced.

Table VII

No polymerization inhibitor properties according to the

!. Inhibitors wt.% 2. inhibitors ppm heating

24h 72h

1 no no polymer abla

ge tion

2 "Sodium Nitiert 100 is low- polymer degradation

docile white bearings

3 triphenyl phosphate 0.5 none ""

4 "0.5 sodium nitrite 100 clear clear

5 tri (n) butylphos- 0.5 none is low- polymer abphat docile white bearings

6 "0.5 sodium nitrite 100 clear clear

Similar experiments are carried out under the same conditions given above, but using dimethylformamide or dimethylacetamide instead of N-methylpyrrolidone as a solvent. In any case, the application of sodium nitrite only (100 ppm) leads to the deposition of the polymer in 72 hours, but if sodium nitrite (100 ppm) and tri-n-buty! phosphate 0.5% by weight) are added, the test solutions remain for 72 hours

then clear.

Example 8

70 parts of acetonitrile, which contains 5% by weight of water, and 30 parts of isoprene are mixed with the addition of the various inhibitors shown below. The corresponding mixtures are reacted in the presence of iron oxide at 120 ° C. and the properties of the products are investigated. The results are given in Table VIII below. » g ^ g, ^ j -j gcc

- 15 -

Table 8

No. Polymerization inhibitor 1st inhibitors% by weight 2nd inhibitors

211270.

State after ppm heating 24 h 48 h

1 no 0.5 no 200 Polymer ablation
rüng Poiymerab-
storage 2 Il 0.5 Sodium nitrite 2OO slightly
White - 3 Il i, o p-tert-butyl
catechin Poiymerablä-
excitement Poiymerabi. 4th Pyridine 1, O no 200 quite cloudy clear 5 If O, 5 Sodium nitrite 1OO clear Ii 6th Il O, 5 Il 200 Il pretty much
cloudy 7th Il i, o p-tert-butyl
catechin slightly
White Polymeräbii 8th. Quinoline 1.0 no 200 quite cloudy clear 9 Il 0.5 Sodium nitrite 100 fclar 10 Il O, 5 Il 200 It quite
cloudy 11th Il 1.0 p-tefct, -Butyl-
katechiη slightly
White Pölymefab-
in stock 12th Anthracene IrO no 200 quite
cloudy clear 13th H ■ sodium nitrite 1OO clear Il 14th Il It 200 η quite
cloudy 15th If p-tert-butyl
catechin slightly
White

Experiments under the same conditions as in experiments 4, 5, -8, 9, 12 and 13 are indicated in Table VIII with except that acetonitrile is replaced by N-methylpyrrolidone or dimethylformamide is replaced. It is then under the conditions corresponding to those of experiments 4, 8 and 12 a slight turbidity observed in 24 hours, while under the conditions corresponding to those after Experiments 5, 9 and 13 the extraction solutions remain clear.

109842/1956

- 16b-

Example 9

Tests are carried out under the same conditions as in the example 6 with the exception that 0.5% by weight of pyridine and 100 ppm of sodium nitrite are used as inhibitors.

The operation is continued for 5 days, but the extraction solution shows no changes and remains clear. If pyridine is replaced by quinoline or anthracene, results are similar to those obtained with pyridine.

In the absence of pyridine, quinoline, anthracene or sodium nitrate the extraction solution begins to turn white and cloudy in 10 hours and a light orange color separates in 20 hours Polymer.

Example 10

Under the same conditions as in Example 8 are given Test solutions with the addition of various specified in Table IX Inhibitors prepared and the mixtures are reacted in the presence of iron oxide at 120 C and then the properties of the Products checked. The results are given in Table IX.

1-0 * 842/19 56 -17-

Table IX

No. Polymerization Inhibitor

!. Inhibitors wt.% 2. inhibitors ppm

2-methylpyridine

2,3-dimethylpyridine

2-methyl-d-ethylpyridine

ω
cn 9 Oi

4-ethylquinoline

2-methylquinoline

0.5 0.5 1.0 1.0

0.5 0.5 1.0

no sodium nitrite

Il

p-tert-butyl-catechin

no sodium nitrate

p-tert-butyl-catechin

0.5 none

0.5 1.0 1.0

0.5 0.5 1.0 1.0

0.5 0.5

Sodium nitrite

p-tett.-butyl-

catechin

no

Sodium nitrided

p-tert-buty 1-catechin

no sodium nitrite

Il

200 100 200

200 100 200

200 100 200

200 100 200

200 100 state after heating 24 h 48 h

quite cloudy
clear

Polymer deposit clear

slightly white rather cloudy

rather cloudy polymer deposit

clear clear

It Il

slightly white rather cloudy

rather cloudy polymer deposit

clear

slightly white rather cloudy

rather cloudy polymer deposit

clear clear

Il Il

slightly white rather cloudy

quite cloudy
clear

Clear polymer deposit

1.0 p-tert-butyl catechol slightly white rather cloudy

Claims (14)

Dipi.-ing. Walter Meissner Dipi.-ing. Herbert Tischer Berlln-Halensee, Kurfüretendamm 130, Account No. 95 716 j b £ r | jn 33 (GRUNEWALD) the JAPAN SYNTHETIC RUBBER CO. Ltd. Herbertotraae 22 claims 1. A method for preventing the polymerization of conjugated dienes in solvents at high temperatures, characterized in that that at least one compound selected from the group consisting of organic phosphoric acid esters of the general formula ROP = O 2 1 ^R 3 where R., R and R are phenyl groups or ring-substituted derivatives are the same whose substituents are alkyl groups, phenyl groups or halogen atoms; Alkyl groups ;, halogen-substituted Alkyl groups or allyl groups; pyridine, ring-substituted Derivatives of pyridine, the substituents of which are alkyl groups, quinoline, nucleus-substituted derivatives of quinoline, their Substituents are alkyl groups, and anthracene is added to a solvent containing the conjugated diene as an inhibitor will. 2. A method for preventing the polymerization of butadiene in a solvent at elevated temperatures, characterized in that that at least one compound selected from the group consisting of organic phosphonic acid esters of the general formula R ₀ -OP = O * I ^R 3 101842/1956 - 2 - where R, R ₂ and R_ are phenyl groups or ring-substituted derivatives thereof, the substituents of which are alkyl groups, phenyl groups or analogues; Alkyl groups; Halogen-substituted alkyl groups or allyl groups represent, a solvent containing butadiene is added as an inhibitor. 3. The method according to claim 2, characterized in that at least a compound selected from the group consisting of pyridine, nucleus-substituted derivatives of pyridino, where the substituents Are alkyl groups. Quinolines, ring-substituted derivatives of quinoline, the substituents of which are alkyl groups, and anthracene can be added as an inhibitor to a butadiene-containing solution. 4. A method for inhibiting the polymerization of isoprene in * a solvent at elevated temperatures, characterized in that at least one compound selected from the group consisting of organic Phosphorsäureestern of the general formula R-O-P = O 0 , ^R 3 where R-, r ^R ₂ and R _{3 represent} a phenyl group or ring-substituted derivatives thereof, the substituents being alkyl groups, phenyl groups or halogen atoms, alkyl groups, halogen-substituted alkyl groups or allyl groups, is added as an inhibitor to a solvent which contains isoprene. 5. The method according to claim 4, characterized in that at least a compound selected from the group consisting of pyridine, nucleus-substituted derivatives of pyridine, their substituents Are alkyl groups, quinoline, ring-substituted derivatives of quinoline, the substituents of which are alkyl groups, and anthracene can be added to a solvent containing isoprene as an inhibitor. BAD ORiG (NAL 109842/1956 6. A method for preventing the polymerization of conjugated dienes according to claims 1, 2 and 4, characterized in that the organic phosphoric acid esters triphenyl phosphate and ring-substituted derivatives thereof, the substituents being alkyl groups represent, phenyl group or halogen atoms, trialkyl phosphates with or without substituted halogen atom, allyl biphenyl phosphate and are diallyl phenyl phosphate. 7. The method according to claim 6, characterized in that the triphenyl phosphates and nucleus-substituted derivatives of the same triphenyl phosphate, tri (o-cresyl) phosphate, tri (rn-cresyl) phosphate _r tri (p-cresyl) phosphate, trixylenyl phosphate, tris (4-tert .-butylphenyl phosphate, tris (o-biphenylyI) phosphate. 8. The method according to claim 6, characterized in that the Trialkyl phosphates and halogen-substituted derivatives of the same Trimethyl phosphate, triethyl phosphate, tri (n) propyl phosphate, tri (i) propyl phosphate, tri (n) butyl phosphate, tri (sec) butyl phosphate, tri (A) amyl phosphate, Trihexyl phosphate, triheptyl phosphate, trioctyl phosphate and represent further organic phosphonic acid esters, the alkyl groups having 1 to 8 carbon atoms; and tri (2-chloroethyl) phosphate, Tri (2-bromoethyl) phosphate, tri (3-chloropropyl) phosphate, Tri (3-bromopropyl) phosphate, tri (3-iodopropyl) phosphate, Tri (2,3-dichloropropyl) phosphate, tri (2,3-dibromopropyl) phosphate, Tri (2,3-diiodopropyl) phosphate, tri (4-chlorobutyl) phosphate, tri (4-bromobutyl) phosphate, Tri (4-iodobutyl) phosphate. 9. The method according to claim 6, characterized in that the organic phosphoric acid esters containing phenyl and allyl groups, which are diallyl phenyl phosphate and allyl biphenyl phosphate. 10. The method according to claim 3, characterized in that the nucleus-substituted derivatives of pyridine are the following: picolines, such as 2-methylpyridine, 3-methylpyridine and 4-methylpyridine; Lutidines such as 2,3-dimethylpyridine, 2,4-dimethylpyridine, 2-ethylpyridine and 3-ethylpyridine; ! Collidines, such as 2-methyl-4-ethylpyridine, 2-methyl-5-ethylpyridine, 2-propylpyridine, 2-isopropylpyridine and 2,4,5-trimethylpyridine; and parvolins such as 2,3,4,5-tetramethylpyridine and 2-butylpyridine. . 109842/1956 11. The method according to claim 3, characterized in that the Nuclear-substituted derivatives of the quinoline alkylquinolines, such as 2-methylquinoline, 3-methylquinoline, 2,3-dimethylquinoline, 3,4-dimethylquinoline, 2-ethylquinoline and 4-ethylquinoline. 12. The method according to any one of the preceding claims, characterized in that the known polymerization inhibitor or Antioxidant for unsaturated compounds is applied as a second polymerization inhibitor. 13. The method according to claim 12, characterized in that the second polymerization inhibitor sodium nitrite, potassium nitrite, Sodium sulfide, a phenolic compound or an aromatic amine compound. 14. The method according to claim 12, characterized in that the the second polymerization inhibitor is sodium nitrite. 109842/1956