Number
053-EN
Section
General Section
Use
Sector
Scientific research and development
Function
pH regulating agent
Process
Use as laboratory reagen
Product category
Processing aids such as pH-regulators, flocculants, percipitant, neutalization agents
Application
Oxygen scavenger used to decrease the corrosion potential of industrial water
Abstract
Hydrazine has been added in 2011 to ECHA’s Candidate List of substances of very high concern for Authorisation under REACH as carcinogen cat. 1B Alternatives to hydrazine as oxygen scavenger in the treatment of industrial water for boilers are presented with a brief comparison of the main technical advantages/limitations.
Substituted substances
Hydrazine
CAS No. 302-01-2 EC No. 206-114-9 Index No. 007-008-00-3
Chemical group
Hydrazin und Hydraziniumsalze
Classification: hazard statements
H226 Flammable liquid and vapour
H350 May cause cancer
H331 Toxic if inhaled
H311 Toxic in contact with skin
H301 Toxic if swallowed
H314 Causes severe skin burns and eye damage
H317 May cause an allergic skin reaction
H400 Very toxic to aquatic life
H410 Very toxic to aquatic life with long lasting effects
Other adverse effects
Der Stoff ist: ein 2B Karzinogen (IARC); wie der Datenbank der nach SUBSPORT-Kriterien gefährlichen Stoffe zu entnehmen ist.
Alternative Substances
Diethylhydroxylamine
CAS No. 3710-84-7 EC No. 223-055-4 Index No.
Chemical group
Hydroxylaminderivate
Carbonohydrazide
CAS No. 497-18-7 EC No. 207-837-2 Index No.
Chemical group
Hydrazinderivate; Harnstoffderivate
Erythorbate
CAS No. 6381-77-7 EC No. 228-973-9 Index No.
Chemical group
Ether
Sodium sulphite
CAS No. 7757-83-7 EC No. 231-821-4 Index No.
Chemical group
Natriumverbindungen; Sulfite
Reliability of information
Internet information: data are from an internet document and only a basic and partial evaluation could be performed
Reason substitution
CMR
skin/respiratory sensitizing
Hazard Assessment
Hydrazine is classified as carcinogen cat. 1B and sensitisation agent (H317) and is listed on the Substance Database according to SUBSPORT Screening Criteria (SDSC). The alternatives have no official classification and are not listed on the SDSC. » Check the Substance Database according to SUBSPORT Screening Criteria (SDSC)
Description of Substitution
Introduction The so-called “oxygen scavengers” are used to treat industrial water in order to reduce the concentration of dissolved oxygen and its corrosion potential that has a negative impact on installations and processes. Hydrazine is an effective oxygen scavenger. It has been added 2011 to ECHA’s Candidate List of SVHC for authorization under REACH as carcinogen cat. 1B. Hydrazine was largely used due to its advantages: does not generate solids in the system or corrosive gases like CO2 and forms a protective film on the metal surface. Hydrazine is often catalysed by hydroquinone or cobalt salts. Due to its hazards hydrazine use should be ceased and several alternatives are available as described below. Diethylhydroxylamine (DEHA) is a volatile metal-passivating oxygen scavenger. In considering thermal and oxidative degradation products, DEHA generates dialkyl amines, acetaldehyde, acetaldoxime and acetic acid. DEHA may be used on its own but is more effective when catalysed by hydroquinone. Carbonohydrazide reacts readily with oxygen at low temperatures and pressures. It is volatile, passivates the metal and does not generate any solids to the system. Carbonohydrazide breaks down to hydrazine at temperatures over 180˚C but this product reacts further with oxygen. This means also that it won’t have hydrazine residues, defeating the purpose of substitution. Carbonohydrazide reaction with oxygen generates carbon dioxide gas that results in corrosive condensate. Erythorbate passivates metal and contributes no solids to the system. It is non-volatile and will not travel with the stream to control oxygen corrosion in the condensate. It is generally regarded as safe (GRAS) by the FDA and can be used in food processing applications. Sodium sulfite is fast reacting and effective. It does not create a protective magnetite film and is ineffective in re-passivating boilers with existing rust. Sulfite reaction with oxygen produces sodium sulfate, a solid, making sulfite inappropriate in high pressure and supercritical boilers. Sodium sulfite is nonvolatile and is not driven by the steam in the condensate system, thus providing no protection to this part. Sulfite breaks down to gases like SO2 and H2S that have a corrosive impact throughout the system. Quinones and cobalt salts are typically used as catalysts for sodium sulfite. Description of procedure or technology (including pre-/post-processing) Way of application: e.g. spraying, dipping, open/closed system etc. Risk management measures (technical, organizational and personal) Risk reduction by alternative: Human health: e.g. more/less safety measures e.g. technical/operational/personal protection measures Risk reduction by alternative: Environment: e.g. waste reduced/increased
Case/substitution evaluation
SUBSPORTplus Comments Hydroquinone (CAS No. 123-31-9) and 2-butanone oxime (CAS No. 96-29-7) are mentioned in the literature as alternatives too. According to the current state of knowledge, they do not meet the SUBSPORT criteria (SDSC) since they are classified as sensitizing substances according to CLP (H317). They could not be recommended on SUBSPORTplus. Operating conditions and the materials that the boilers and the rest of the steam system are made of can limit the use of some of the alternatives, as described above.
State of implementation
In use
Date and place of implementation
2001 in USA
Availability of Alternative
Alternatives are available on the market.
Producer/Provider
https://www.arkema-americas.com/en/
Type of information supplier
Producer / distributor
Further information
1. IARC acetaldehyde">http://monographs.iarc.fr/ENG/Monographs/vol71/mono71-11.pdf">acetaldehyde monograph
2. Report on toxicology">http://ntp.niehs.nih.gov/ntp/htdocs/ST_rpts/tox051.pdf">toxicology MEKO
3. Technical">https://www.baua.de/DE/Angebote/Rechtstexte-und-Technische-Regeln/Regelwerk/TRGS/TRGS-608.html">Technical Rule for Hazardous Substances (TRGS) 608 Substitutes, substitution of working methods and restrictions on use for hydrazine in water- and vapour systems (1991, amended 1993) (in German)
Publication source: author, company, institute, year
https://www.arkema-americas.com/en/
Date, reviewed
February 27, 2020