Eliminate the nitrosamines in manufacturing processes

Nitrosamines refers to the Group of compounds for nitrous amines derivatives. Those known as N-nitrosamines contain nitrous Group joined the amine nitrogen. These substances are known for their possible induction to cancer by causing DNA mutations and, as a result, there are many efforts for both the establishment of test methods enabling their control in the final product as well as the study of alternatives and methods of disposing of them in articles more likely to contain them. Some matrices in which it is possible the detection of the nitrosamines are: smoke tobacco, cured meats, pesticides, beer, and cosmetics.

However is in the industry of the rubber where more has been able to study the learning of the same discovering, for example, that form by the action of some acelerantes that contain secondary amines, which, by means of the action of the agent nitrosante generates the corresponding nitrosamina. Some of the agents nitrosantes known are NO⁺, N₂Or₃, N₂Or₄ and others from atmospheric gaseous reactions. The presence of these agents is due to other additives like preservatives or contaminantes atmospheric common. In any case, the sources of the agents nitrosantes are very miscellaneous and, often, depend on the chemical composition of specific mixes and of formulations.
In the industry of the rubber, besides is possible to find nitrosaminas that have been deliberately added to the formulations. It is the case of the N-Nitrosodifenilamina (NDPA) which acts like agent retardante and, besides takes part in the learning of the N-Nitrosodimetilamina (NDMA).

The presence of secondary amines, precursors of N-Nitrosaminas, in addition to coming from of the acelerantes and even of some agents antidegradantes, also find presents in some synthetic rubbers derived of ditiocarbamatos, hidroxilaminas or disulfitos of thiuram employed in the processes of polymerisation.

One of the articles formed by rubber, and in consequence, susceptible to contain nitrosaminas, are the tetinas of the chupetes and of the biberones. It exists a regulation concerning the content in N-Nitrosaminas and substances N-Nitrosables in said articles marked by the Directive 93/11/CEE with the following limits: maximum limit of migration of N-Nitrosaminas; 0,01 mg / kg and maximum limit for the migration of N-Nitrosables; 0,1 mg / kg . Fortunately it exists a method of available essay in shape of norm: it JOINS-IN 12868 Methods to determine the release of N-Nitrosaminas and substances N-Nitrosables by the tetinas and the chupetes of rubber or elastomers. In the articles of puericultura, this methodology applies to the rubber, to the silicone and to the thermoplastic elastomers.

The N-Nitrosaminas controlled by this method are:

• N-Nitrosodimetilamina (NDMA),
• N-Nitrosodietilamina (NDEA),
• N-Nitrosodipropilamina (NDPA),
• N-Nitrosodibutilamina (NDBA),
• N-Nitrosopiperidina (NPIP),
• N-Nitrosopirrolidina (NPYR),
• N-Nitrosomorfolina (NMOR),
• N-Nitrosodibenzilamina (NDBzA),
• N-Nitrosodiisononilamina (NDiNA),
• N-Nitroso N-metil N-fenilamina (NMPhA) and
• N-Nitroso N-etil N-fenilamina (NEPhA).

The reduction or elimination of the N-Nitrosaminas produced during the vulcanización can tackle from distinct punto:

• elimination or reduction of the learning of the secondary amines of the acelerantes of the vulcanización and of the agents donors of sulphur. 
• creation of conditions of reaction that do not favour the learning of the N-Nitrosaminas employing sour ascórbico or to-tocoferol.
• elimination of the agents nitrosantes.
• elimination of the N-Nitrosaminas formed.

In some cases, is possible the reduction of the nitrosaminas by means of the employment of agents antidegradantes free of amines. Nevertheless, it results much more difficult to substitute the acelerantes traditional as well as the donores of sulphur without sacrificing some properties of the final product.

However, the problem is very complex and precise of a much more exhaustive investigation that allow to know the exact mechanisms of the learning of these compounds to be able to delete them of the processes of manufacture. In consequence, are necessary the investigations directed to the control of these products