Bisphenol S

Names
IUPAC name 4,4'-Sulfonyldiphenol
Other names BPS, 4,4'-sulfonylbisphenol, bis(4-hydroxyphenyl)sulfone
Identifiers
CAS Registry Number	80-09-1 Y
ChEMBL	ChEMBL384441 Y
ChemSpider	6374 Y
InChI InChI=1S/C12H10O4S/c13-9-1-5-11(6-2-9)17(15,16)12-7-3-10(14)4-8-12/h1-8,13-14H Y Key: VPWNQTHUCYMVMZ-UHFFFAOYSA-N Y InChI=1/C12H10O4S/c13-9-1-5-11(6-2-9)17(15,16)12-7-3-10(14)4-8-12/h1-8,13-14H Key: VPWNQTHUCYMVMZ-UHFFFAOYAO
Jmol-3D images	Image Image
KEGG	C14216 Y
PubChem	6626
SMILES O=S(=O)(c1ccc(O)cc1)c2ccc(O)cc2 c1cc(ccc1O)S(=O)(=O)c2ccc(cc2)O
Properties
Chemical formula	C12H10O4S
Molar mass	250.27 g·mol−1
Appearance	White colorless solid; forms needle shaped crystals in water
Density	1.3663 g/cm3
Melting point	245 to 250 °C (473 to 482 °F; 518 to 523 K)
Solubility in water	insoluble
Solubility	soluble in ethanol
Hazards
R-phrases	R36
S-phrases	S26
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Bisphenol S (BPS) is an organic compound with the formula (HOC₆H₄)₂SO₂. It has two phenol functional groups on either side of a sulfonyl group. It is commonly used in curing fast-drying epoxy resin adhesives. It is a bisphenol, and a close analog of bisphenol A (BPA) in which the dimethylmethylene group (C(CH₃)₂) is replaced with a sulfone group (SO₂).

Use[edit]

BPS is used in curing fast-drying epoxy glues and as a corrosion inhibitor. It is also commonly used as a reactant in polymer reactions.

BPS has become increasingly common as a plasticizing agent following the widespread bans on the use of BPA due to its estrogen-mimicking properties, and BPS can now be found in a variety of common consumer products.^[2][3] In some cases, BPS is used where the legal prohibition on BPA allows products containing BPS to be labelled "BPA free".^[4] BPS also has the advantage of being more stable to heat and light than BPA.^[5]

To comply with restrictions and regulations on BPA due to its confirmed toxicity, manufacturers are gradually replacing BPA with other related compounds, mainly bisphenol S (BPS; 4,4′-sulfonyldiphenol), as substitutes in industrial applications.^[6]

BPS is also used as an anticorrosive agent in epoxy glues. Chemically, BPS is being used as a reagent in polymer reactions. BPS has also been reported to occur in canned foodstuffs, such as tin cans.^[7]

In a recent study analyzing BPS in a variety of paper products worldwide, BPS was found in 100% of tickets, mailing envelopes, airplane boarding passes, and airplane luggage tags. In this study, very high concentrations of BPS were detected in thermal receipt samples collected from cities in the United States, Japan, Korea, and Vietnam. The BPS concentrations were large but varied greatly, from a few tens of nanograms per gram to several milligrams per gram. Nevertheless, concentrations of BPS used in thermal paper are usually lower compared to those of BPA.^[8] Finally, BPS can get into the human body through dermal absorption from handling banknotes.^[9]

Health and safety[edit]

Recent work suggests that, like BPA, BPS also has endocrine disrupting properties.^[10] What makes BPS, and BPA, endocrine disruptors is the presence of the alcohol group on the benzene ring. This is called a phenol ring and it allows BPA and BPS to mimic estradiol. In a study of human urine BPS was found in 81% of the samples tested.^[11] This percentage is comparable to BPA which was found in 95% of urine samples.^[12] Another study done on thermal receipt paper shows that 88% of human exposure to BPS is through receipts.^[13] In rodent studies BPS also has shown influenced uterine growth which indicates activation of estradiol.^[14]

BPS has been shown to have similar in vitro estrogenic activity to BPA and acts as a xenoestrogen.^[5][15][16] One study showed that exposure to low levels of BPS in cultured rat pituitary cells altered the estrogen estradiol signaling pathway to induce inappropriate release of prolactin, which, as a result, affected cell proliferation and apoptosis.^[15]

BPS has also been linked to changes in neurodevelopment. In a 2014 study performed by researchers at the University of Calgary, exposure to low levels of BPS disrupted the timing of neurogenesis within the hypothalamus in embryonic zebrafish. The rate at which neurons developed increased by 240 percent.^[17]

The recycling of thermal paper can introduce BPS into the cycle of paper production and cause BPS contamination of other types of paper products.^[18][19] A recent study showed presence of BPS in more than 70% of the household waste paper samples, potentially indicating spreading of BPS contamination through paper recycling. ^[20]

BPS is more resistant to environmental degradation than BPA, and although not persistent cannot be characterised as readily biodegradable.^[21][22]

History[edit]

BPS was first made in 1869 as a dye ^[23] and is currently common in everyday consumer products. BPS is an analog of BPA that has replaced BPA in a variety of ways, being present in thermal receipt paper, plastics, and indoor dust.^[10] After health concerns associated with bisphenol A grew in 2012, BPS began to be used as a replacement.^[24]

Regulation[edit]

It is difficult for consumers to determine if a product contains BPS due to limited labeling regulations.^[25]

Synthesis[edit]

Bisphenol S is prepared by the reaction of two equivalents of phenol with one equivalent of sulfuric acid or oleum.^[26]

2 C₆H₅OH + H₂SO₄ → (C₆H₄OH)₂SO₂ + 2 H₂O

2 C₆H₅OH + SO₃ → (C₆H₄OH)₂SO₂ + H₂O

This reaction can also produce 2,4'-sulfonyldiphenol, a common isomeric complication in electrophilic aromatic substitution reactions.

References[edit]