DE1230425B - Process for the preparation of N, N'-diaryluretediones - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

German class:

C07d

12 ρ -10/01

Number: 1230425

File number: J21928IVd / 12ρ

Filing date: June 13, 1962

Opening day: December 15, 1966

In the French patent 1 204 697 the polymerization of mono- and polyisocyanates described in trimeric polymers, which contain the structure of isocyanuric acid by the isocyanates treated with an organic base having a hydroxyl group. Tolylene-2,6-diisocyanate is one of those diisocyanates stated to be used in this process can. However, it is directed to the production of trimers of the isocyanurate structure, and it will not indicated that it can be used for the production of dimers or uretedione derivatives.

The main patent 1 081 895 relates to a process for the preparation of Ν, Ν'-diaryluretediones and triaryl isocyanuric acid esters by di- or trimerization of aryl isocyanates which contain at least one isocyanate group and which should be unsubstituted in the o-position to the isocyanate group to be reacted, which is characterized that the reaction at a temperature between -40 and + 140 ⁰ C, preferably between 0 and 100 ⁰ C, in the presence of a pyridine of the formula

is carried out, wherein Xi is a residue

/ Ri

means in which Ri is an alkyl or aryl radical and R2 is an alkyl radical or Ri and R ₂ together represent an alkylene radical, which can also be interrupted by a heteroatom, and X2 has the same meaning as Xi, but also an alkoxy or aryloxy radical and one of the symbols Xi and X2 can mean a hydrogen atom.

According to this known method, an aryl mono- or polyisoeyanate which has no substituent has in the ortho division to an isocyanate group, are polymerized. By the presence such an ortho-substituent is a polymerization, in particular a dimerization, prevented.

It has now surprisingly been found that a certain aryl diisocyanate which has a substituent in ortho division to the two isocyanate groups, namely tolylene-2,6-diisocyanate, processes for the preparation of
Ν, Ν'-diaryluretediones

Addendum to the patent: 1081 895

Applicant:

Imperial Chemical Industries Limited, London

Representative:

Dr.-Ing. H. Fincke, Dipl.-Ing. H. Bohr
and Dipl.-Ing. S. Staeger, patent attorneys,
Munich 5, Müllerstr. 31

Named as inventor:

James Harry Wild,

Manchester, Lancashire (UK)

Claimed priority:

Great Britain June 16, 1961 (21 840)

can be rapidly dimerized by this process.

The invention thus relates to a process for the preparation of Ν, Ν'-Diaryluretedionen by dimerization of aryl isocyanates at a temperature between -40 and +100 ⁰ C, preferably at room temperature, in the presence of a pyridine of the general formula

X ₂

where Xi is a residue

/ Ri

- N <

means in which Ri is an alkyl or aryl radical and R2 is an alkyl radical or Ri and R2 together are one Represent an alkylene radical, which can also be interrupted by a heteroatom, and X2 has the same

609 747/323

has the same meaning as Xi, but also has an alkoxy or aryloxy radical and one of the symbols Xi and X2 can be a hydrogen atom, according to Patent 1,081,895, which is characterized in that that the reaction is carried out with tolylene-2,6-diisocyanate.

The same catalysts and polymerization conditions can be used for the process according to the invention can be used as in the procedure of the main patent.

The process product can be used in particular as a hardening or vulcanizing agent for resins and used to make homogeneous or cellular products.

The invention is explained in more detail in the following example. The parts and weights relate to weight, unless otherwise noted.

example

A solution of 1.5 parts of 4-dimethylaminopyridine in 28 parts of dry ethyl acetate was mixed with 3600 parts of 2,6-tolylene diisocyanate. After 2 days, the resulting solid was broken under a solution of 61 parts of acetyl chloride in 13,110 parts of benzene, filtered and washed with benzene to give 3100 parts of a solid product. After recrystallization from benzene the N, N'-bis (2-methyl-3-isocyanatophenyl) -uretedion was obtained as a white crystalline solid in the form which melts at 165-166 ⁰ C (uncorrected).

The product was analyzed by reaction with piperidine. An equivalent weight of 113.4, 113.6 was found. The calculated equivalent weight is 116. An elemental analysis of the product gave the following values: C = 62.3%, H = 3.5%, N = 16.3%. A compound of the formula Ci ₈ Hi ₂ N ₄ O ₄ contains C = 62.1%, H = 3.4%, N = 16.1%.

The infrared spectrum showed bands at 4.35μ due to free isocyanate groups, 5.63μ due to the Uretedione rings and at 12.86 and 14.27 μ due to the 1,2,3-trisubstituted benzene rings, from which it can be seen that the product obtained from Ν, Ν'-bis (2-methyl-3-isocyanatophenyl) uretedione consists.

Claims (1)

Claim: Process for the production of. N, N'-diaryluretediones by dimerization of aryl isocyanates at a temperature between -40 and + 100 ° C, preferably at room temperature, in the presence of a pyridine of the general formula X ₂ where Xi is a residue - N < means in which Ri is an alkyl or aryl radical and R2 is an alkyl radical or Ri and R2 together represent an alkylene radical which can also be interrupted by a heteroatom, and X _{2 has the} same meaning as Xi, but also an alkoxy or aryloxy radical and one of the symbols Xi and X ₂ can mean a hydrogen atom, according to patent 1081895, characterized in that the Re-. action is carried out with tolyene-2,6-diisocyanate. Considered publications:
German Patent No. 1,081,895;
French patent specification No. 1 204 697.