Tetrakis(hydroxymethyl)phosphonium sulfate
[CAS# 55566-30-8]

Identification

• Classification: Chemical reagent >> Organic reagent >> Phosphorous compound
• Name: Tetrakis(hydroxymethyl)phosphonium sulfate
• Synonyms: Octakis(hydroxymethyl)diphosphonium sulfate
• Molecular Formula: C₈H₂₄O₁₂P₂S
• Molecular Weight: 406.28
• CAS Registry Number: 55566-30-8
• EC Number: 259-709-0
• SMILES: C(O)[P+](CO)(CO)CO.C(O)[P+](CO)(CO)CO.[O-]S(=O)(=O)[O-]

Properties

• Melting point: -35 °C
• Boiling point: 111 °C
• Water solubility: >=10 g/100 mL at 18 °C

Safety Data

• Hazard Symbols: GHS05;GHS06;GHS07;GHS08;GHS09 Danger
• Risk Statements: H301-H302-H317-H318-H330-H331-H360-H361-H361d-H372-H400-H410-H411
• Safety Statements: P203-P260-P261-P264-P264+P265-P270-P271-P272-P273-P280-P284-P301+P316-P301+P317-P302+P352-P304+P340-P305+P354+P338-P316-P317-P318-P319-P320-P321-P330-P333+P317-P362+P364-P391-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Serious eye damage	Eye Dam.	1	H318
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Skin sensitization	Skin Sens.	1	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Acute toxicity	Acute Tox.	3	H331
Acute toxicity	Acute Tox.	4	H302
Reproductive toxicity	Repr.	2	H361
Acute toxicity	Acute Tox.	3	H301
Skin sensitization	Skin Sens.	1A	H317
Acute toxicity	Acute Tox.	2	H330
Reproductive toxicity	Repr.	2	H361d
Reproductive toxicity	Repr.	1B	H360
Acute toxicity	Acute Tox.	3	H302
Specific target organ toxicity - repeated exposure	STOT RE	1	H372
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Skin corrosion	Skin Corr.	1B	H314
Acute toxicity	Acute Tox.	5	H333
Acute toxicity	Acute Tox.	5	H313
Specific target organ toxicity - single exposure	STOT SE	3	H335

Discovery and Applications

Tetrakis(hydroxymethyl)phosphonium sulfate (THPS) is a water-soluble organophosphorus compound widely used in industrial and water treatment applications. It is synthesized through the reaction of phosphine with formaldehyde in the presence of sulfuric acid, producing a stable sulfate salt. The compound is known for its biocidal properties and has been extensively studied and utilized in various fields due to its effectiveness as a microbiocide and flame retardant.

THPS is primarily employed as a biocide in water treatment, particularly in controlling microbial growth in industrial cooling systems, oilfield operations, and paper manufacturing. Its strong antimicrobial activity enables it to inhibit the growth of bacteria, fungi, and algae in recirculating water systems, thereby preventing biofilm formation and equipment fouling. It has been used in oil and gas applications to control sulfate-reducing bacteria, which are responsible for microbial-induced corrosion and hydrogen sulfide generation in pipelines and reservoirs.

In textile and leather industries, THPS is applied as a tanning agent and flame retardant. It enhances the fire resistance of fabrics and leather materials by incorporating phosphorus-based flame-retardant properties. Additionally, it has been utilized in the paper industry to improve the durability and microbial resistance of treated products.

THPS exhibits favorable environmental characteristics compared to some traditional biocides. It is known for its rapid degradation under environmental conditions, reducing its persistence and potential accumulation in ecosystems. This property makes it a preferred choice in applications where biodegradability is a consideration. Regulatory bodies have evaluated its use, and its application is subject to compliance with safety and environmental guidelines.

The compound's stability in aqueous solutions and effectiveness across a range of pH conditions contribute to its versatility in industrial processes. However, proper handling and dosing are required to optimize its biocidal activity while minimizing potential environmental impact. Due to its strong antimicrobial properties, THPS continues to play a significant role in industrial water treatment, microbial control, and material protection across multiple industries.

References

2024. Advanced Janus coatings for thermal management and synergistic flame retardancy in polyester fabric. Journal of Materials Chemistry A, 12(38).
DOI: 10.1039/D4TA04320K

2016. Phosphorus-containing polymers from THPS. VII. Synthesis of phosphorus-containing trialkynes and their metal-free 1,3-dipolar cycloaddition reaction with azidated soybean-oil. Green Chemistry, 18(5).
DOI: 10.1039/C5GC01919B

2014. Phosphorus-containing polymers from tetrakis-(hydroxymethyl)phosphonium sulfate iii. A new hydrolysis-resistant tris(allyloxymethyl)phosphine oxide and its thiol-ene reaction under ultraviolet irradiation. RSC Advances, 4(78).
DOI: 10.1039/C4RA06080F