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Hydrolysis

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Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

other information

Study period:

2010

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

unsuitable test system

Data source

Reference

Reference Type:

publication

Title:

Degradation of 10-Methacryloyldecyl dihydrogen phosphate

Author:

Teshima I

Year:

2010

Bibliographic source:

J Dental Res Vol. 89 No.11 pp. 1281-1286

Report date:

2010

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: 0.5 mmol of 10-methacryloyloxydecyl dihydrogen phosphate or 2-methacryloyloxyethyl dihydrogen phosphate were dissolved in a 5 mol% aqueous solution of N-methacryloyl glycine or hydroxyethyl methacrylate and stored. Period samples were analyzed by 13C-NMR
- Short description of test conditions: After formulation of reaction mixtures, they were incubated at 40 ± 0.5 °C for 1, 3, 6, 10, and 14 weeks. NMR scans were done immediately after formulation and after each of the storage periods. Solution pH was measured by pH meter after formulation and at weeks 6 and 14.
- Parameters analysed / observed: relative peak intensity of specific peaks were used to identify parent and hydrolysis products. Hydrolytic rates were determined relative to the other methacrylate-phosphate material and were not reported as absolute rate constants. Rate data is thus not reported.

GLP compliance:

no

Remarks:

published study

Test material

Test material information

Constituent 1

Reference substance name:

10-(phosphonooxy)decyl methacrylate

Molecular formula:

C14H27O6P

IUPAC Name:

10-(phosphonooxy)decyl methacrylate

Study design

Analytical monitoring:

yes

Duration of test

Duration:

14 wk

pH:

2

Temp.:

40 °C

Initial conc. measured:

0.5 mmol/L

Results and discussion

Transformation products:

yes

Identity of transformation products

Identity of transformation products 1

No.:

#1

Identity of transformation products 2

No.:

#2

Reference

Reference substance name:

Unnamed

IUPAC name:

methacrylic acid

Inventory number:

InventoryMultipleMappingImpl [inventoryEntryValue=EC 201-204-4]

CAS number:

79-41-4

Identity:

2-Propenoic acid, 2-methyl-

Molecular formula:

C4H6O2

Molecular weight:

86.089

SMILES notation:

CC(=C)C(=O)O

InChl:

InChI=1/C4H6O2/c1-3(2)4(5)6/h1H2,2H3,(H,5,6)

Identity of transformation products 3

No.:

#3

Reference

Reference substance name:

Unnamed

IUPAC name:

decane-1,10-diol

Inventory number:

InventoryMultipleMappingImpl [inventoryEntryValue=EC 203-975-2]

CAS number:

112-47-0

Identity:

1,10-Decanediol

Molecular formula:

C10H22O2

Molecular weight:

174.28

SMILES notation:

OCCCCCCCCCCO

InChl:

InChI=1/C10H22O2/c11-9-7-5-3-1-2-4-6-8-10-12/h11-12H,1-10H2

Details on hydrolysis and appearance of transformation product(s):

The carbon shifts followed for 10-methacryloyloxydecyl dihydrogen phosphate are depicted in the illustration. Specific 13C NMR shifts followed included the methacrylate carbonyl (d) and methylene (a) carbons, the terminal and subterminal carbons on either side of decane-1,10-diol (e, g, zeta). Neither the central 8 carbons of decane-1,10-diol (f) nor the remaining methacrylate carbons provided useful information. Differential results were found when 10-methacryloyloxydecyl dihydrogen phosphate was co-incubated with N-methacryloyl glycine (NMG) v. 2-hydroxyethyl methacrylate (HEMA). In particular, a small peak for the d- and a- carbons (methacrylate carbonyl and methylene) developed in the HEMA co-incubation but not in the NMG co-incubation. The new peaks were attributed to hydrolysis of the phosphate ester on the opposite side of the structure. No such difference was found in the e- or g-carbons adjacent to the acrylate and phosphate, respectively, for hydrolysis of the opposite moiety. Also, while the decane-1,10-diyl terminal carbons could be distinguished between intact and hydrolyzed forms, the hydrolyzed 1- and 10-carbons could not be distinguished: these carbons appeared identical whether in 10-hydroxydecyl dihydrogen phosphate, 10-hydroxyoxydecyl methacrylate, or decan-1,10-diol. Similar behavior was found for the subterminal carbon (labeled zeta after hydrolysis). Initial hydrolysis of the phosphate group in the HEMA co-incubation was concluded, but hydrolysis of the phosphate ester could not be demonstrated by the NMR results. The authors concluded that they phosphate ester hydrolyzed due to acidification of the test solution over the course of the experiment (initial pH 1.90 and 1.84, final pH 1.67 and 1.58 for the NMG and HEMA experiments, respectively).

Results with reference substance:

2-methacryloxyethyl dihydrogen phosphate was also tested. In this case, the three hydrolysis products could clearly be distinguished on the NMR spectra, indicating complete hydrolysis of the molecule.

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Conclusions:

10-methacryloyloxydecyl dihydrogen phosphate, a constituent of MDP, hydrolyzes to form decane-1,10-diol under acidic conditions (pH <2)

Executive summary:

Hydrolytic behavior of the 10-methacryloyloxydecyl dihydrogen phosphate of MDP was studied in acidic conditions using 13C NMR. The test material was co-incubated with 5 mole percent of N-methacryloyl glycine or 2-hydroxyethyl methacrylate for 14 weeks. Acidity of the solutions increased during the incubation. Chemical shift data indicated hydrolysis of the molecule, and decrease in solution pH was taken as evidence that hydrolysis led to 1,10-decanediol. Hydrolysis rate was expressed relative to 2-methacryloyloxydecyl dihydrogen phosphate. The experiment appears to have been conducted well. However, given the extreme reaction conditions the test system is considerable unsuitable and the result is not considered reliable.