Isosaccharinic acid

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Isosaccharinic acid
Names
IUPAC name
3-Deoxy-2-C-(hydroxymethyl)-D-erythro-pentonic acid
Systematic IUPAC name
(2S,4S)-2,4,5-Trihydroxy-2-(hydroxymethyl)pentanoic acid
Other names
D-gluco-Isosaccharinic acid; Isosaccharinic acid; α-D-Glucoisosaccharinic acid; α-D-Isosaccharinic acid; α-Glucoisosaccharinic acid; α-Isosaccharinic acid
Identifiers
3D model (
JSmol
)
ChemSpider
UNII
  • InChI=1S/C6H12O6/c7-2-4(9)1-6(12,3-8)5(10)11/h4,7-9,12H,1-3H2,(H,10,11)/t4-,6-/m0/s1 ☒N
    Key: SGOVJIDEXZEOTB-NJGYIYPDSA-N ☒N
  • InChI=1/C6H12O6/c7-2-4(9)1-6(12,3-8)5(10)11/h4,7-9,12H,1-3H2,(H,10,11)/t4-,6-/m0/s1
    Key: SGOVJIDEXZEOTB-NJGYIYPDBR
  • OC[C@@H](O)C[C@@](CO)(O)C(O)=O
Properties
C6H12O6
Molar mass 180.156 g·mol−1
Melting point 189 to 194 °C (372 to 381 °F; 462 to 467 K)[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Isosaccharinic acid (ISA) is a six-carbon

nuclear waste stores when cellulose is degraded by the calcium hydroxide in cements such as Portland cement. The calcium salt
of the alpha form of ISA is very crystalline and quite insoluble in cold water, but in hot water it is soluble.

ISA is thought to form by means of a series of reactions in which calcium ions acting as

diketone (1,5,6-trihydroxyhexane-2,3-dione) which is formed from the carbohydrate.[2]

Under acidic conditions sugars tend to form

5-hydroxymethylfurfural by a series of dehydrations of the carbohydrate
.

In acidic solutions the acid tends to form a 5-membered ring (

anthracyclines.[4][3]

Relevance for nuclear waste disposal

Since 1993, the diastereomers of isosaccharinic acid have received particular attention in the literature due to its ability to complex a range of radionuclides, potentially affecting their migration.[5][6][7] ISA is formed as a result of interactions between cellulosic materials present within the intermediate level waste inventory various countries and the alkalinity resulting from the use of cementitious materials in the construction of a deep geological repository.[8] Greenfield et al. (1993), have discovered that ISA and constituents formed in a cellulose degradation leachate were capable of forming soluble complexes with thorium, uranium (IV) and plutonium.[9][5][10] In the case of plutonium, ISA concentrations higher than 10−5 M were capable of increasing solubility above pH 12.0, where concentrations of 1-5 × 10−3 M were found to increase the solubility by an order of magnitude from 10−5 to 10−4 M. Allard et al. (2006) found that a concentration of ISA of 2 × 10−3 M could increase plutonium solubility by a factor of 2 × 105.[11] In addition a range of studies on the complexation properties of α-isosaccharinic acid in alkaline solutions with various metals of different valence, including nickel (II), europium (III), americium (III) and thorium (IV), have been conducted.[12][13][14][15][16]

Vercammen et al. (2001) showed that although Ca(α-ISA)2 is sparingly soluble,[17] both europium (III) and thorium (IV) were capable of forming soluble complexes with ISA between pH 10.7 and 13.3, where a mixed metal complex was observed in the presence of thorium.[12] Wieland et al. (2002) also observed that α-ISA prevented the uptake of thorium by hardened cement pastes.[15] Warwick et al. (2003) have also shown that ISA is capable of influencing the solubility of both uranium and nickel through complexation.[13][14] Tits et al. (2005) observed that in the absence of ISA, europium, americium and thorium will sorb onto calcite aggregates present in concrete within an ILW GDF.[16] Should ISA concentrations within the disposal facility exceed 10−5 mol L−1 (2 × 10−5 mol L−1 in the case of Th(IV)), it was reported that the sorption onto calcite would be significantly affected such that the radionuclides studied would no longer be sorbed to the cement and instead be complexed by ISA.

The effect of cellulose degradation products on radionuclide solubility and sorption is the subject of a study from 2013.[18] Cellulose degradation product leachates were first produced by contacting cellulose sources (wood, rad wipes or cotton wool) with calcium hydroxide (pH 12.7) under anaerobic conditions. Analysis of the leachates across 1 000 days suggested that the primary product of the degradation was ISA, although a range of other organic compounds were formed and varied across cellulose source. In these experiments both ISA and X-ISA were able to increase the solubility of europium at pH 12, where in experiments with thorium ISA had a more profound effect on thorium solubility than X-ISA, for which little effect was observed.

More recently, a systematic study was published on the interactions between plutonium, ISA, and cement, as well as sorption.[19] The investigation was focused on repository-like conditions, including high pH due to cementitious materials and low redox potential. The predominant species at various conditions were identified, including quaternary materials such as Ca(II)Pu(IV)(OH)3ISA–H+. The sorption of Pu on cement was found to be significantly lowered due to complexation with ISA.

Microbial activity in a geological disposal facility

ISA also represents a major carbon source within a geological disposal facility (GDF) since it comprises >70% of cellulose degradation products as a result of

alkaline hydrolysis of organic matter in situ. This consortia was readily capable of degrading ISA.[23] It can also exist as polymicrobial flocculates, which has shown to be able of survival up to pH 12.5.[24] As a result, the impact of microbial activity within a GDF is expected to be through the degradation of ISA's and production of gas, which may create overpressure but also through the generation of 14C bearing gases.[25]

See also

References

  1. doi:10.1021/ja01551a031
    .
  2. ISSN 0002-7863
    .
  3. ^
    ISSN 0022-3263
    .
  4. ^
    ISSN 0040-4039
    .
  5. ^
    doi:10.1557/PROC-333-705
    .
  6. ISSN 0003-2670
    .
  7. ISSN 0144-8617
    .
  8. ^ Humphreys, P.N.; Laws, A; Dawson, J. (2010). "A review of cellulose degradation and the fate of degradation products under repository conditions. SERCO/TAS/002274/001. Serco contractors report for the Nuclear Decommissioning Authority (NDA), UK". NDA. Retrieved 5 May 2019. Download pdf.
  9. ^ Greenfield, B.F.; Hurdus, M.H.; Spindler, M.W.; Thomason, H.P. (1997). The effects of the products from the anaerobic degradation of cellulose on the solubility and sorption of radioelements in the near field (Technical report). AEA Technology plc, Harwell, Didcot, Oxfordshire, UK.: Nirex. NSS/R376 and/or NSS/R375.
  10. ISSN 1946-4274
    .
  11. S2CID 96594970
    .
  12. ^
    S2CID 96697782
    .
  13. ^
    S2CID 94105533
    .
  14. ^
    S2CID 98370926
    .
  15. ^
    S2CID 95331441
    .
  16. ^
    ISSN 0883-2927
    .
  17. S2CID 91844805
    .
  18. ^ Randall, M.; Rigby, B.; Thomson, O.; Trivedi, D. (2013). "Assessment of the effects of cellulose degradation products on the behaviour of europium and thorium NNL (12) 12239 Part A – Issue 4 National Nuclear Laboratory, Chadwick House, Warington, UK". NDA. Retrieved 4 May 2019.
  19. S2CID 104816503
    .
  20. PMID 25062127
    .
  21. PMID 25268118
    .
  22. PMID 26367005
    .
  23. PMID 25748643
    .
  24. PMID 26195600
    .
  25. ISSN 0026-461X
    .

External links
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