CS257803B1 - A method for modifying nitrosamphins - Google Patents

Abstract

The solution deals with a method of modifying nitrosamines, such as N-methyl-N-nitrosourea, 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane and/or 1,3,S-trinitroso-ξ,3,5-triazacyclohexane, and/or a method of modifying a mixture based on nitrosamines, carried out by adding one part by weight of N,N-biscarbamoylhydrazine to two to twelve parts by weight of nitrosamine. The procedure is useful especially in the production and application of lightening systems based on nitrosamines

Description

It is an object of the present invention to provide a process for modifying nitrosamines and / or mixtures thereof.

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Nitrosamines, as thermodynamically unstable substances, may be subject to explosive transformations uncontrolled. In technically attractive products based on them, this undesirable property is suppressed by phlegmatization and / or dilution with inert additives. However, in the case of rubber and plastic blowing agents with nitrosamines as active ingredients, traditional phlegmatizing agents, such as water, mineral or silicone oils, may adversely affect the quality of the product to be bottled.

In order to meet the requirements of special and new applications of nitrosamines, in particular in the field of lightweight materials and / or products, it is sought to modify the properties of the said nitroso compounds to suit intensification and innovation measures in the national economy. In particular, it is an increase in the thermal stability, physical stability and curing efficacy of the blowing agents based on 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacycloctane, as well as the elimination of an unpleasant odor in the blowing agents of the aforementioned type.

According to the present invention, the properties of nitrosamines such as N-methyl-N-nitrosourea, 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane and / or mixtures thereof are modified by the addition of Ν, Ν '. -biscarbamoylhydrazine, also called hydrazodicarboxamide, in an amount of one part by weight of said substance to two to twelve parts by weight of nitrosamine.

An advantage of the present invention is the dilution of nitrosamine, that is, suppression of the risk of fire, respectively. explosion, a readily synthetically available additive that itself is virtually non-flammable.

The modification process according to the invention leads to an increase in the heat stability of the nitrosamines and / or the mixture thereof, which is a further advantage of the invention, in the case of 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacycloctocane and the blowing agent based on it is the higher effect of the process according to the invention to significantly increase the gas yield from its decomposition and the correspondingly higher curing efficacy and, last but not least, the fact that the modifying additive, i.e. N, N'-biscarbamoylhydrazine, here application of the above blowing agents in the rubber industry.

The process of modifying nitrosamines and / or mixtures thereof based on the addition of N, N'-bicarbamoylhydrazine has not been described in the literature and is documented by the following examples, which in no way exclude the possible variability of the process according to the invention.

Example 1

Technical N-methyl-N-nitrosourea (code-named MNU) and technical Ν, Ν'-biscarbamoylhydrazine are available. A mixture of 10 wt. parts MNU per 1 wt. % of the hydrazine derivative.

Using differential thermal analysis (DTA), operating at a linear temperature rise rate of 5 ° C.min ~ ^, measuring range of 1 mV per scale scale, paper feed rate at 20 mm.mn ¹ and weighing 30 to 50 mg of sample, Specified thermostability characteristics of both initial and additive MNU; The following overview presents the results:

sample beginning exo dec (° C) The first peak of exo-decomposition <C) Second peak exo dec (° C) MNU starting point 79.0 117.5 122.2 MNU with additive 82.2 118.3 122.2

The results in the table document the stabilizing effect of Ν, Ν'-biscarbamoylhydrazine on N-methyl-N-nitrosourea.

Example 2

Technical 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane containing 4.9 wt. 1,3,5-trinitroso-1,3,5-triazacyclohexane and the Ν, Ν'-biscarbamoylhydrazine of Example i. A mixture of 2.09 wt. parts of technical nitrosamine per 1 wt. % of the hydrazine derivative. With the DTA of Example 1, an onset of exothermic decomposition at 110.5 ° C is found at the starting 1,5-methano--3,7-dinitroso-1,3,5,7-tetraazacyclooctane at 110.5 ° C and, in the case of a mixture, an onset of exothermic decomposition at 143.1 ° C. Here, a marked stabilizing effect of Ν, Ν'-biscarbamoylhydrazine is evident.

Example 3

From a raw material as in Example 2, a rubber kaolin and a mineral oil, a mixture is prepared having the composition (wt.%): 65% and 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacycloctocane, 20% Ν, Ν'-biscarbamoylhydrazine, 10% kaolin and 5% oil. With the DTA of Example 1, an onset of exothermic decomposition at 137.9 ° C is found in this mixture, which provides a marked increase in stability over the starting technical nitrosamine.

Example 4

From the raw materials of Example 2 and Example 3, a mixture having the composition (wt.%): 56.8% is prepared.

1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane, 13% Ν, Ν'-biscarbamoylhydrazine, 21% kaolin and 9.2% oil. With the DTA of Example 1, an onset of exo-decomposition at 141.2 ° C is found in this mixture, which in turn is a marked increase in stability over the starting nitrosamine.

Example 5

The compositions of Examples 3 and 4 are tested under standard conditions as blowing agents in a rubber composition; the reference blowing agent is a commercial mixture of Chempor PC 65 containing 65 wt.

% 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane; urea complex with methyllurea, respectively. % with methylenebismurea and 14.5 wt. water.

In the first phase of testing, the same amount of blowing agent is always dosed per 1000 g of the test rubber composition, i.e. 24 g, and mixing the composition of Examples 3 and 4 is better than Chempor PC 65. Comparison of growth properties of blowing agents after vulcanization 8 min at 155 ° C) from the test specimen aspect gives:

Chempor PC 65 ................... 87 mm mixture according to example 3 ............. ....... 89 mm mixture according to example 4 ................... 87 mm

From these results, it can be seen that the mixtures of Examples 3 and 4 are 1.02 to 1.14 times more effective than Chempor PC 65. Evaluation of the vulcanization properties under the same batch of blowing agents yields the following values on the G * ttfert at 155 ° C. :

blowing agent M. min (Nm) M max (Nm) % 1 (with) ^» at 90 (s) Chempor PC 65 0.15 0.49 180 624 according to example 3 0.15 0.35 432 750 according to Example 4 0.09 0.30 378 726

A tabular overview of the results demonstrates that the blends of Examples 3 and 4 less affect the vulcanization properties of the rubber blend than the commercial Chempor PC 65 blend.

In the second phase of testing, the dosage of blowing agents per 1000 g of the rubber mixture is adjusted as follows:

Chempor PC 65 ................................ 24 g mixture according to example 3 ......... ............... 20 g mixture according to example 4 ........................ 24 g

A comparison of the growth properties under the same vulcanization conditions as in the previous gives in all three cases the same diameter of the test body - 87 mm; Thereby, the efficiency of the composition of Examples 3 and 4 is documented 1.1 to 1.2 times higher than the commercial composition of Chempor PC 65. The evaluation of the vulcanization properties on a Gottfert elestograph at 155 ° C gives the following values in this case:

blowing agent M. min (Nm) M max (Nm) % 1 (s) ^FC v 90 (s) Chempor PC 65 0.11 0.37 306 666 according to example 3 0.09 0.29 402 720 according to Example 4 0.11 0.29 396 648

In this case too, the lesser effect of the blend of Examples 3 and 4 on the vulcanization system is seen, as shown by Chempor PC 65.

In the third stage of testing, for the purpose of specifying the pressure curve, acceleration of the basic rubber mixture is carried out by standard addition of accelerators at the expanding of the blowing agents as in the second phase; evaluation of vulcanization properties at 155 ° C gives values of:

blowing agent M. min (Nm) ^M max (Nm) ^« b 1 (s) ^FC v 90 (s) F. _{/ c} · 1/5 min. (KN) Chempor PC 65 0.17 0.62 186 552 1.44 according to example 3 0.16 0.50 246 732 0.96 according to Example 4 0.17 0.53 252 708 0.99

This evaluation also shows a lesser effect of the blends of Examples 3 and 4 on the vulcanization system than Chempor PC 65. For this reason, the measured 5 minute pressure for the blends of Examples 3 and 4 is lower than that of the Chempore PC 65 ( here is already a higher degree of vulcanization in 5 minute rating).

The deodorizing capacity of the blowing agent is also assessed in all three stages of the evaluation (testing): this ability of the mixture of Examples 3 and 4 is comparable to Chempor PC 65.

The mixtures of Examples 3 and 4 retained their consistency (flowability) for the entire warranty period (6 months), while the commercial mixture solidified to hard after one month (curing of urea-formaldehyde condensates in Chempore PC 65).

Note: in tabular overviews this example means

M. - minimum torque mm * ^M max ” ^maximum Y torque ie j - processing safety t gg - optimum vulcanization time

F. is the force (pressure) to be applied in the 5th minute of vulcanization to eliminate 1/5 mm.

oiu pressure in the measuring cell.

Example 6

Technical 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane containing 7.3 wt. 1,3,5-trinitroso-1,3,5-triazacyclohexane, technical N, N'-biscarbamoylhydrazine and technical isopropyllated triphenylphosphate, manufactured in Czechoslovakia under the trade name Retar 131.

Mixtures are prepared from these raw materials:

Mixture A: consists of 90 wt. % by weight of technical 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane; Ν, Ν'-biskarbamoylhydrazínu;

Mixture B: consists of 83.4 wt. % by weight of technical 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazaoyclooctane; % Ν, Ν'-biscarbamoylhydrazine and 7.4 wt. Retar 131;

For the above mixtures as well as for the starting 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane at 190 ° C, a gas number indicating the effectiveness of the blowing agent is determined:

Blowing agent Gas number? gas per 1 g of pure DNPT, 3-1.

(cm .g) in the mixture

Mixture A 280 Mixture B 250 Initial DNPT 240

311

300

240

Note: DNPT = 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane;

The table below shows a very significant positive effect of Ν, Ν'-biscarbamoylhydrazine on the recovery of blowing agent gases.

Example 7

Mixtures of technical 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane and Ν, Ν'-biscarbamoylhydrazine are prepared from raw materials as in Example 2, in which they are the method of thermal explosion according to H. Henkin and R. McGilla (see Ind. Eng. Chem. 1952, 44, No. 06, 1391-1395) determined the induction periods of explosion in the temperature range of 190 to 210 ° C and the activation energies of the explosion are calculated from them; the results are presented in the table:

Weight ratio DNTP to HAC Activating energy flash point (kJ.mol 2) Induction periods (in seconds) extrapolated to 150 ° C averaged at 190 ° C 1: 0 53.94 213.8 50.3 1: 1 66.75 278.7 54.0 2: 1 63.48 238.5 50.1 4: 1 61.61 223.6 49.2 6: 1 60.74 216.7 48.7

It can be seen from the summary that the addition of Ν, Ν'-biscarbamoylhydrazine (code in the HAC table) ^: to the technical 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane (code in the table DNPT) it increases its thermal stability for the temperature range up to 150 ° C in all presented cases and for the region above 150 ° C for the DNPT to HAC weight ratios up to · 2: 1.

Claims (2)

257803 6 OBJECT OF THE INVENTION A method for modifying nitrosamines such as N-methyl-N-nitrosourea, 1,5-methano-3,7-dinitroso-1,3,5,7-tetraazacyclooctane and / or mixtures thereof, to increase their thermal stability and extracting the gaseous effluents of their deodorizing thermolysis in their optional application as blowing agents, characterized in that Ν, Ν-biscarbamoylhydrazine is added to said nitrosamines and / or mixtures thereof to one to two to twelve parts of nitrosamine. 2. Process according to claim 1, characterized in that one part by weight of N, N'-biscarbamoylhydrazine is added to 2.09 to 10 parts by weight of nitrosamine.