Oxidising agents for the neutralisation of dangerous gases

Number

134-EN

Section

General Section

Use

Sector

Manufacture of bulk, large scale chemicals (including petroleum products)
Manufacture of fine chemicals

Function

Oxidizing agent

Process

Chemical production or refinery in closed process without likelihood of exposure or processes with equivalent containment conditions.
Chemical production or refinery in closed continuous process with occasional controlled exposure or processes with equivalent containment conditions

Product category

laboratory chemicals

Application

Production of pharmaceutical products

Abstract

Mercaptans (thioalcohols) and sulphur compounds are by-products in some pharmaceutical production processes. These compounds are toxic and smell very bad. For neutralisation the company previously used hydrogen peroxide, which is a very reactive chemical. Now they are using sodium hypochlorite instead.

Substituted substances

Hydrogen peroxide

CAS No. 7722-84-1 EC No. 231-765-0 Index No. 008-003-00-9

Chemical group

Peroxides

Classification: hazard statements

H271 May cause fire or explosion; strong oxidiser
H332 Harmful if inhaled
H302 Harmful if swallowed
H314 Causes severe skin burns and eye damage

Alternative Substances

Sodium hypochlorite

CAS No. 7681-52-9 EC No. 231-668-3 Index No. 017-011-00-1

Chemical group

Sodium compounds; hypochlorites

Classification: hazard statements

H314 Causes severe skin burns and eye damage
H318 Causes serious eye damage
H400 Very toxic to aquatic life
H410 Very toxic to aquatic life with long lasting effects

Reliability of information

Evidence of implementation: there is evidence that the solution was implemented and in use at time of publication

Reason substitution

ecotoxicity
physical hazards
other reasons

Hazard Assessment

Substance to be substituted: Sodium hypochlorite is corrosive. Hydrogen peroxide is harmful if swallowed and is harmful if inhaled, causes severe skin burns and eye damage and may cause fire or explosion (strong oxidiser). Alternative substance: The alternative is corrosive as well and is much less reactive. Hydrogen peroxide is, however, very toxic to aquatic life with long lasting effects and causes serious eye damage, causes severe skin burns and eye damage.

Description of Substitution

During the production of pharmaceuticals several by-products are formed. Among others, there are hazardous gases like mercaptans (thioalcohols) and other sulphur compounds. These are poisonous, smell very bad and must be neutralised. In order to neutralise mercaptan and sulphur gases the Danish company added hydrogen peroxide, which is that it is a highly reactive substance that can release oxygen hereby producing an overpressure. This overpressure can be a risk to human health and the equipment if the process gets out of control. Moreover the reaction generates a lot of heat and the cooling process, to avoid explosion, is energy consuming. In addition, hydrogen peroxide is corrosive. Moreover it was difficult for the company to buy hydrogen peroxide, because it requires an approval by the Danish authorities prior to ordering the hydrogen peroxide due to the explosive potential of the chemical. Therefore the company started to look for alternatives. They combined their knowledge about organic chemical processes with a systematic review of well-defined and publicly available “unit operations” for the chemical industry. Hydrogen peroxide was substituted by sodium hypochlorite. Sodium hypochlorite is as efficient as hydrogen peroxide, but it is not as reactive as hydrogen peroxide. Sodium hypochlorite is, in contrast to hydrogen peroxide , very toxic to aquatic life with long lasting effects. Therefore the company now has to modify their waste water treatment.

Case/substitution evaluation

The alternative is not included in the database of hazardous substances according to SUBSPORTplus screening criteria (SDSC), however according to the hazard statements it holds problematic properties. Among others, the environmental risks have to be adequately controlled. Therefore, further research is needed to replace this substance in the future.

State of implementation

Full capacity

Date and place of implementation

1988, Denmark

Availability ofAlternative

On the market

Type of information supplier

User

Contact

http://www.leo-pharma.com www.leo-pharma.com

Date, reviewed

December 11, 2020