Sodium hydroxymethanesulfinate

Structural formula
General
Surname	Sodium hydroxymethanesulfinate
other names	Sodium formaldehyde sulfoxy acid Hydroxymethanesulfinic acid sodium salt Sodium formaldehyde sulfoxylate Rongalit
Molecular formula	CH 3 NaO 3 S
Brief description	white solid with a sulfur-like odor
External identifiers / databases
CAS number 149-44-0 6035-47-8 (dihydrate) EC number 205-739-4 ECHA InfoCard 100.005.219 PubChem 23689980 ChemSpider 8649 Wikidata Q3492820
properties
Molar mass	118.08 g mol −1
Physical state	firmly
density	1.744 g cm −3
Melting point	63 ° C (dihydrate)
solubility	easily soluble in water (1000 g l −1 at 25 ° C)
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 341-361 EUH: 032 P: 201-202-281-308 + 313-405-501
Toxicological data	> 2000 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Sodium hydroxymethanesulfinate is an inorganic chemical compound from the group of substituted sulfinic acid derivatives and alcohols . The compound is on the EU's list of CoRAP substances .

Extraction and presentation

Sodium hydroxymethanesulfinate can be obtained by reacting sodium dithionite with formaldehyde in the presence of alkali , by catalytic reduction of sodium hydroxymethanesulfonate with hydrogen and by a number of other preparation methods.

${\displaystyle \mathrm {Na_{2}S_{2}O_{4}+2\ CH_{2}O+H_{2}O\longrightarrow HO\cdot CH_{2}-SO_{3}Na+HO-CH_{2}-SO_{2}Na} }$

properties

Sodium hydroxymethanesulfinate is a flammable, difficult to ignite, hygroscopic, white solid with a sulfur-like odor, which is easily soluble in water. It decomposes above 125 ° C, producing methanethiol , hydrogen sulfide , some formaldehyde and sulfur dioxide . It is odorless after production, but quickly develops its characteristic odor. The dihydrate gives off its water of crystallization at 120 ° C shortly before the decomposition temperature .

use

Sodium hydroxymethanesulfinate was brought onto the market by BASF in 1905 as "Rongalit C" for the discharge printing of cotton and for vat dyeing . In pharmacy, the compound is used as a preservative, antioxidant and stabilizer in drugs.

Risk assessment

Sodium hydroxymethanesulfinate was included by the EU in 2016 in accordance with Regulation (EC) No. 1907/2006 (REACH) as part of substance evaluation in the Community's rolling action plan ( CoRAP ). The effects of the substance on human health and the environment are re-evaluated and, if necessary, follow-up measures are initiated. Ingestion of sodium hydroxymethanesulfinate was caused by concerns about worker exposure , high (aggregated) tonnage and widespread use, as well as the possible dangers of carcinogenic, mutagenic and reproductive toxicity properties. The re-evaluation is to be carried out by the Netherlands from 2021 .

Individual evidence

1. ↑ ^{a b c d e f g h i} Entry on sodium hydroxymethanesulfinate in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .
2. ↑ ^{a b c} Franz v. Bruchhausen, Siegfried Ebel Eberhard Hackenthal, Ulrike wooden grave: Hager's Handbook of Pharmaceutical Practice sequel 5: fabrics L-Z . Springer-Verlag, 2013, ISBN 978-3-642-58388-9 , pp. 275 ( limited preview in Google Book Search).
3. ↑ R. Haller: Chemical Technology of Cotton / Mechanical Aids for Finishing Cotton Textiles 3rd Part . Springer-Verlag, 2013, ISBN 978-3-642-90897-2 , p. 210 ( limited preview in Google Book search).
4. ↑ Community rolling action plan ( CoRAP ) of the European Chemicals Agency (ECHA): Sodium hydroxymethanesulphinate , accessed on March 26, 2019.