Reaction products of boric acid and lithium hydroxide

Auto flammability

Link to relevant study record(s)

Reference

Endpoint:

relative self-ignition temperature (solids)

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

A self-heating substance as follows: a solid or liquid substance or mixture, by reaction with air and without energy supply, is liable to self-heat; this substance or mixture differs from a pyrophoric liquid or solid in that it will ignite only when in large amounts (kilograms) and after long periods of time (hours or days).

The self-heating potential of substances is based on chemical structure and susceptibility of molecular bonds to oxidation. All lithium borate substances in this category do not have any molecular bonds which are susceptible to oxidation. In addition, they have a similar chemical composition where any variations due to the range of trigonal and tetrahedral species between the substances are not expected to lead to any changes in their self-heating potential. Read-across to the result for dilithium tetraborate is therefore proposed.

Key result

Remarks on result:

other: No self-ignition temperature noted.

Remarks:

Negative outcome (no effect observed)

Conclusions:

It can be concluded that the UVCB-Reaction products of boric acid and lithium hydroxide is not a self-heating solid and therefore not subject to transportation restrictions of UN Class 4 Division 4.2.

Executive summary:

For solids, self-heating may occur by reaction with air with subsequent ignition. According to the CLP Regulation, Annex I, section 2.11, a self heating substance or mixture is a liquid or solid substance or mixture, other than a pyrophoric liquid or solid, which, by reaction with air and without energy supply, is liable to self-heat. Therefore the self ignition temperature of solids are considered under self heating and as a result, the UN Test N.4 is preferable for solids to generate information for this endpoint.

 

Under the conditions of UN Test N.4, the results excluded dilithium tetraborate as a self-heating solid. Self-heating properties are based on chemical structure and susceptibility of molecular bonds to oxidation. The UVCB-Reaction products of boric acid and lithium hydroxide has a very similar chemcial structure to dilithium tetraborate; any variations due to the range of trigonal and tetrahedral species between the substances are not expected to lead to any changes in their self-heating potential.  It can therefore be concluded that the UVCB-Reaction products of boric acid and lithium hydroxide is not a self-heating solid and therefore not subject to transportation restrictions of UN Class 4 Division 4.2.

Description of key information

Lithium tetrahydroxyborate has a very similar chemical structure to dilithium tetraborate; any variations due to the range of trigonal and tetrahedral species between the substances are not expected to lead to any changes in their self-heating potential.  It can therefore be concluded that the UVCB-Reaction products of boric acid and lithium hydroxide is not a self-heating solid.