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Biodegradable chelating agent: HIDS™

Product Biodegradable chelating agent: HIDS™
Structure chemical structure
Chemical name Tetrasodium 3-Hydroxy-2,2'-Iminodisuccinate
Chemical formulas C8H7NO9•4Na
Molecular weight 353.1
CAS No.1 190195-65-4
Appearance Pale yellow~yellow, liquid
Form 50wt% aqueous solution
pH 10±1 (25 C)
Density 1.40~1.60 (20 C)
Applications Household and I&I cleaner, Textile processing, Bleach stabilization, Photography, Paper and Pulp processing, Scale removal and prevention, Metal treatment working, Water treatment, Agriculture, Cosmetics use, etc.

Specifications may be changed without notice.


Prospective applications

Please investigate legal regulations and industry standards for your applications by yourself.

Ecological information

Biodegradability Biodegradable (MITI test) (*1)
Fish toxicity LC50 >2,000 mg/L (Medaka (Oryzas latipes) 96 hr) (*1)

Toxicological Information

Acute toxicity LD50(rat)>2,000mg/L (*1)
Local effects •Primary skin irritation(rabbit)
Not irritating ( PII=0.4 (45 wt%), PII=0 (35 wt%) ,PII=0 (10 wt%) , PII=0 (89 wt%,powder)) (*1)
•Primary eye irrtation (rabbit)
Not irritating (*1)
Sensitization No skin sensitization (Maximization Test) (*1)
Mutagenicity(AMES text) Negative (*1)

(*1) These data were obtained by a certified laboratory.

Regulatory information

ENCS (2)-3803
TSCA Inventory Listed
ELINCS Not listed

Handling and Storage

Protective equipments

Eye protection
Safety glasses with side shields, goggles, a face shield.
Hand protection
Chemical resistant gloves.
Skin and Body protection
Safety clothes and shoes.

Data are extracted from Material Safety Data Sheet (SDS, HPI-1521-00-00).
SDS (HPI-1521-00-00) is available on request.


US 6063302
'Method for handling iminocalboxylic acid salt' (NIPPON SHOKUBAI CO., LTD.)

HIDS Properties

Acid dissociation constants and stability constants

Acid dissociation constants pKa1: 2.83
pKa2: 3.56
pKa3: 5.15
pKa4: 9.11
Complex Stability constants pKaCa2+: 4.8
pKaFe3+: 12.5
C.V. value 300 mg CaCO3/g

Fe3+chelating capability

graph (*) Residual Fe3+: Ratio of the Fe3+ dispersing in the solution after the test to the initial Fe3+

HIDS forms water-soluble complexes with various kinds of metal ions over a wide range of pH. In particular, it shows superior performance in chelating Fe3+ ion in alkaline solution.

Test solution HIDS (or EDTA): 0.01M
Fe3+: 0.01M
Temperature Room temperature
Experimental procedure The test solution was allowed to stand at room temperature for one week. The solution was then filtered to separate the sediment (hydrated Fe compounds), and Fe3+ concentration in the filtrate was determined by inductively coupled plasma (ICP).

Thermal stability and pH stability


HIDS shows high stability in harsh conditions. HIDS is stable at high temperature and at a range of pH 4-13.

Condition HIDS : 10%
Temperature : 80 C
Experimental procedure The test solution was incubated at 80 C, and aliquots were sampled at the indicated hours. The residual HIDS amount was measured using high-performance liquid chromatography (HPLC).

Solubility in alkaline solution


HIDS is highly soluble in aqueous alkaline solutions. Therefore, HIDS can be added into concentrated alkaline solutions without solubilizing agents.

Measurement temperature 0 C

Solubilization of water-insoluble calcium salt

graph (*) Calcium salt solubilization ability: Ratio of the dissolved Ca salt to the initially added calcium salt.

HIDS is able to solubilize water-insoluble calcium salt, which is the main component of scales. HIDS effectively removes scales in tanks and tubes, and prevents scale generation.

Test solution Water-insoluble calcium salt: 0.6%
Chelating agent: 0.2%
NaOH: 3%
Temperature: 80 C
Experimental procedure The test solution was stirred at 80 C for one hour, and the concentration of dissolved Ca2+ was measured

Glass corrosion


HIDS is less corrosive to glasses compared with other chelating agents.

Test solution NaOH: 10%
Chelating agent: 3%
Test piece: Slide glass
Temperature: 100 C
Experimental procedure The test pieces were placed in the test solution for three days at 100 C. Those pieces were weighed after washing, and the corrosion degree was calculated from the weight change.


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