Sodium Methylparaben is a chemical compound that belongs to the paraben chemical family.
The name defines the structure of the molecule:
- Sodium (Na). Sodium is an alkaline metal, a group of highly reactive elements found in group 1 of the periodic table. Sodium is soft and silvery-white in color. It is highly reactive, especially with water, and is commonly found in salts and minerals.
- Methylparaben refers to the methyl ester of p-hydroxybenzoic acid. Parabens are a type of preservative used in a variety of cosmetic and pharmaceutical products.
Description of the raw materials used in its production.
- Methylparaben acid - This is the primary active ingredient that, once neutralized, becomes the preservative known as Sodium Methylparaben. It has antimicrobial and fungicidal properties.
- Sodium hydroxide (or lye) - Used as a neutralizing agent. When added to methylparaben acid, it neutralizes it to form the salt, Sodium Methylparaben.
- Water - Serves as a solvent and reaction medium. It facilitates the mixing and reaction between the methylparaben acid and sodium hydroxide.
The synthesis process takes place in several stages:
- Preparation. Methylparaben is synthesized by esterification of p-hydroxybenzoic acid with methanol. This reaction is usually catalyzed by an acid and involves heating the reagents to promote the reaction.
- Neutralization. Methylparaben is neutralized with sodium hydroxide (NaOH) to produce sodium methylparaben with salt formation from the acid (Methylparaben ) and base (NaOH). The reaction is carried out in an aqueous solution.
- Crystallization. Sodium Methylparaben is isolated from the reaction mixture by crystallization. This involves cooling the reaction mixture to induce the formation of Sodium Methylparaben crystals.
- Filtration and drying. Sodium Methylparaben crystals are separated from the reaction mixture by filtration and dried to remove all remaining water.
- Quality control test. The final product is tested to ensure it meets the required specifications with tests for purity, moisture content and other physical and chemical properties.
It occurs in the form of a fine white powder.
What it is used for and where
It is a preservative used in food, pharmaceuticals, cosmetics and more.
Cosmetics
It is a restricted ingredient as V/12 a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported: 4-Hydroxybenzoic acid and its Methyl- and Ethyl-esters, and their salts
- Preservative. Any product containing organic, inorganic compounds, water, needs to be preserved from microbial contamination. Preservatives act against the development of harmful microorganisms and against oxidation of the product.
Pharmaceuticals
- Sodium Methylparaben is used as a preservative in oral solutions, such as those containing sodium valproate. An HPLC method was developed for the simultaneous determination of sodium valproate, methylparaben, and propylparaben in oral solutions
Safety
Like all members of the Paraben family, it can give allergies.
Sodium Methylparaben as a preservative is widely used in our lives, but it will damage health if the human body absorbs large quantities of it. So there are strict rules about the dosage of Sodium Methylparaben in each country (1).
Parabens
Parabens are chemical preservative compounds that have been the subject of attention in the scientific literature as possible endocrine disruptors (particularly propylparaben and butylparaben), i.e. with the possibility of damaging the hormone-producing glands in our bodies, particularly in the breasts. The 2004 study by Darbre et al. showed that parabens remain in our bodies as intact esters (2). Following this study, some of the scientific literature in 2005 and 2006 cast doubt on Darbre's conclusions and claimed they were limited. However, both the US FDA and the European SCCP authorised in 2006 the use of a single paraben in cosmetic products at a concentration of 0.4% and the use of total parabens at a concentration of 0.8% (3). However, there is no shortage of studies that consider the restrictions unnecessary: M. G. Kirchhof et al. in 2013 found that parabens are among the safest and most well-tolerated preservatives and that current data do not support drastic regulations or personal exposure restrictions (4). Darbre in 2014 published a further study in which he showed how parabens can cause DNA damage (5).
Sodium Methylparaben studies
Typical optimal commercial product characteristics Sodium methylparaben
| Appearance | White fine powder |
Boiling Point
| 265.5ºC at 760 mmHg |
Melting Point
| >125°C |
Flash Point
| 116.4ºC |
| pH | 9.5-10.5 (1g/l, H2O) |
| Sulphate | ≤0.12% |
| Chloride | ≤350ppm |
| PSA | 49.36000 |
| LogP | 1.61700 |
| Water% | 5.0 Max. |
Heavy metal (Pb, ppm)
| 10 Max. |
| Safety |  |
- Molecular Formula C8H7O3Na C8H7NaO3
- Molecular Weight 174.131 g/mol
- Exact Mass 174.029282
- UNII CR6K9C2NHK
- CAS 5026-62-0
- EC Number: 225-714-1
- DSSTox Substance ID DTXSID1042156
- IUPAC sodium;4-methoxycarbonylphenolate
- InChI=1S/C8H8O3.Na/c1-11-8(10)6-2-4-7(9)5-3-6;/h2-5,9H,1H3;/q;+1/p-1
- InChl Key PESXGULMKCKJCC-UHFFFAOYSA-M
- SMILES COC(=O)C1=CC=C(C=C1)[O-].[Na+]
- PubChem Substance ID 329769369
- MDL number MFCD00016470
- Beilstein Registry Number 4165000
Synonyms:
- Methyl 4-hydroxybenzoate sodium salt
- Sodium 4-(methoxycarbonyl)phenolate
- Sodium methylparaben
- Methylparaben sodium
- Methylparaben, sodium salt
- sodium;4-methoxycarbonylphenolate
- Sodium Methyl Parahydroxybenzoate
- sodium 4carbomethoxyphenolate
- Methyl p-hydroxybenzoate, sodium salt
- Sodium p-methoxycarbonylphenoxide
- Sodium methyl p-hydroxybenzoate
- Benzoic acid, 4-hydroxy-, methyl ester, sodium salt
- Sodium methyl 4-hydroxybenzoate
- sodium 4-methoxycarbonylphenolate
- Methyl p-hydroxybenzoate sodium
- Preserval MS
- Solparol
- Bonomold OMNa
- Methyl 4-hydroxybenzoate sodium salt
- Sodium 4-carbomethoxyphenolate
Bibliografia_______________________________________________
(1) Wang ST, Chen DY, Hou PG, Wang XL, Wang ZF, Wei M. Determination of the Sodium Methylparaben Content Based on Spectrum Fluorescence Spectral Technology and GA-BP Neural Network. Guang Pu Xue Yu Guang Pu Fen Xi. 2015 Jun;35(6):1606-10.
(2) Darbre PD, Aljarrah A, Miller WR, Coldham NG, Sauer MJ, Pope GS. Concentrations of parabens in human breast tumours. J Appl Toxicol. 2004 Jan-Feb;24(1):5-13. doi: 10.1002/jat.958.
(3) https://www.fda.gov/cosmetics/cosmetic-ingredients/parabens-cosmetics
Cosmetic Ingredient Review Expert Panel. Final amended report on the safety assessment of Methylparaben, Ethylparaben, Propylparaben, Isopropylparaben, Butylparaben, Isobutylparaben, and Benzylparaben as used in cosmetic products. Int J Toxicol. 2008;27(Suppl 4):1-82.
(4) Kirchhof MG, de Gannes GC. The health controversies of parabens. Skin Therapy Lett. 2013 Feb;18(2):5-7.
(5) Darbre PD, Harvey PW. Parabens can enable hallmarks and characteristics of cancer in human breast epithelial cells: a review of the literature with reference to new exposure data and regulatory status. J Appl Toxicol. 2014 Sep;34(9):925-38. doi: 10.1002/jat.3027.
Sodium Methylparaben 
Methyl 4-hydroxybenzoate
