Product Details
CasNo： 99-76-3
MF： C8H8O3
Appearance： powder
Delivery Time： 15 days
Packing： 25kg/drum
Purity： 99%
1. Basic Information
Common Name: Methylparaben
IUPAC Name: Methyl 4-hydroxybenzoate
Synonyms: Nipagin M, p-Hydroxybenzoic acid methyl ester
Chemical Formula: C8H8O3
Molecular Weight: 152.147 g/mol
CAS Number: 99 - 76 - 3
2. Physical and Chemical Properties
2.1 Appearance
It usually presents as a white crystalline powder or colorless crystals at room temperature and normal pressure, with no odor or a very slight, almost imperceptible, characteristic smell.
2.2 Melting Point
The melting point of methylparaben ranges from 125 - 128 °C. When heated to this temperature range, it changes from a solid state to a liquid state. This property is crucial in manufacturing processes that involve melting and blending it with other substances.
2.3 Boiling Point
It has a relatively high boiling point of 270 - 280 °C (at normal pressure). However, it should be noted that it may decompose before reaching this boiling point under certain conditions. The high boiling point indicates its stability at elevated temperatures within a certain range.
2.4 Solubility
Methylparaben is highly soluble in organic solvents such as alcohols (e.g., ethanol, methanol), ethers (e.g., diethyl ether), and acetone. This solubility in organic solvents makes it easy to incorporate into formulations containing these solvents. However, it is only extremely slightly soluble in water. This limited water solubility is a characteristic that needs to be considered when formulating products for aqueous systems, often requiring the use of solubilizing agents or specific formulation techniques to ensure its homogeneous distribution.
2.5 Density
The density of methylparaben is approximately 1.358 g/cm³. Density is an important physical property as it affects the amount of the substance in a given volume, which is relevant in dosage calculations and formulation design, especially in industries like pharmaceuticals and cosmetics where precise ingredient ratios are crucial.
2.6 Stability
It is a stable and non - volatile compound under normal storage conditions. This stability ensures that its chemical properties remain unchanged over an extended period, as long as it is stored properly, away from extreme temperatures, humidity, and light. It does not easily decompose or evaporate, which is highly beneficial for its long - term use in various products.
3. Production Process
Typically, methylparaben is produced through an esterification reaction. The main raw materials are p - hydroxybenzoic acid and methanol. In the presence of a catalyst, such as concentrated sulfuric acid, the reaction occurs as follows:
C7H6O3+CH3OHconcentrated H2SO4⟶ΔC8H8O3+H2O
During the production process, strict control of reaction conditions is required. The reaction temperature is usually maintained within a certain range (e.g., around 60 - 80 °C), and the reaction time is carefully monitored. Pressure is generally kept at normal or slightly elevated levels. The ratio of raw materials also significantly impacts the reaction yield. After the reaction, a series of separation and purification processes are carried out. This includes distillation to remove excess methanol and other low - boiling substances, crystallization to isolate the methylparaben product, and filtration to obtain a pure solid product. These processes aim to remove unreacted raw materials, catalysts, and by - products, resulting in a high - purity methylparaben suitable for various applications.
4. Product Advantages
4.1 Broad - Spectrum Antimicrobial Activity
Methylparaben exhibits remarkable inhibitory effects against a wide range of microorganisms, including various molds, yeasts, and bacteria. Its antibacterial mechanism involves multiple aspects. Firstly, it can disrupt the structure and function of the microbial cell membrane, increasing its permeability and causing the leakage of intracellular substances. Secondly, it can denature intracellular proteins, thereby inactivating essential enzymes and other proteins required for the normal physiological functions of microorganisms. Additionally, it inhibits the activity of the respiratory enzyme system and the electron transport enzyme system in microbial cells, ultimately leading to the inhibition of microbial growth and reproduction. This broad - spectrum antibacterial property makes it an ideal preservative in many products, effectively preventing product spoilage and extending the shelf life of products in industries such as food, cosmetics, and pharmaceuticals.
4.2 High Safety Profile
- Toxicity Studies: Acute toxicity studies in animals have shown that methylparaben is relatively non - toxic when administered orally or parenterally. For example, in rat subcutaneous injection experiments, the LD50 (lethal dose 50, the dose at which 50% of the test animals die) is greater than 500 mg/kg. In normal - skinned human populations, it is essentially non - irritating and non - sensitizing. However, it should be noted that in some individuals, there have been reports of contact dermatitis reactions upon cutaneous exposure. Although the exact mechanism of this sensitivity is not fully understood, it is considered to be a relatively rare occurrence.
- Chronic Administration Studies: In chronic administration studies, no - observed - effect levels (NOEL) as high as 1050 mg/kg have been reported, and a no - observed - adverse - effect level (NOAEL) in rats of 5700 mg/kg has been proposed. These results suggest that methylparaben has a relatively high safety margin under normal usage conditions.
4.3 Good Compatibility
Methylparaben can be well - combined with a variety of other raw materials in product formulations. In the food industry, it can co - exist with various food ingredients such as flavors, colors, sweeteners, and thickeners without causing chemical reactions that would affect the quality or taste of the food. In the cosmetics industry, it can be stably incorporated into formulations containing different types of oils, surfactants, humectants, and emulsifiers. This good compatibility ensures that it can function effectively as a preservative while maintaining the overall stability and performance of the product.
4.4 Cost - Effectiveness
Compared with some new - generation or natural preservatives, methylparaben has a relatively low production cost. The raw materials p - hydroxybenzoic acid and methanol are relatively inexpensive and widely available. The production process is also relatively mature and does not require highly complex or expensive equipment. This cost - effectiveness allows manufacturers in different industries to use it as a reliable preservative option while effectively controlling production costs, which is one of the main reasons for its widespread use in the market.
5. Application Areas
5.1 Food Industry
- Function as a Preservative: Methylparaben is widely used as a food preservative in a variety of food products. In beverages such as fruit juices, carbonated drinks, and dairy - based beverages, it can prevent the growth of spoilage - causing microorganisms, thereby maintaining the clarity, flavor, and nutritional value of the beverages. In bakery products like bread, cakes, and pastries, it inhibits the growth of molds and yeasts, extending the shelf life of these products and preventing them from going stale or developing moldy spots. It is also used in processed foods such as jams, jellies, sauces, and pickles to prevent microbial contamination and spoilage.
- Dosage Requirements: The dosage of methylparaben in food products is strictly regulated by food safety authorities in different countries. For example, in the United States, the Food and Drug Administration (FDA) has set specific limits on its usage levels in various food categories to ensure consumer safety. Generally, the maximum allowable concentration in food products is usually in the range of a few hundred parts per million (ppm), depending on the type of food.
5.2 Cosmetics Industry
- Common Applications: Methylparaben is a commonly used preservative in the cosmetics industry. It can be found in almost all types of cosmetic products. In skincare products such as creams, lotions, serums, and facial masks, it prevents the growth of bacteria and fungi, ensuring the product remains free from contamination and maintains its efficacy and texture over time. In haircare products like shampoos, conditioners, and hair gels, it serves the same purpose, protecting the product from microbial degradation. It is also used in color cosmetics such as lipsticks, eyeshadows, and foundations to prevent the growth of microorganisms that could cause discoloration, odor, or a change in texture.
- Safety Considerations in Cosmetics: Although methylparaben is generally considered safe for use in cosmetics, some consumers and environmental groups have raised concerns about its potential long - term effects. However, regulatory agencies in many countries, such as the European Union's European Chemicals Agency (ECHA) and the US FDA, have evaluated its safety and determined that when used within the approved concentration limits, it poses no significant risk to human health. The maximum allowable concentration in cosmetics is typically around 0.4% (w/w) for single esters and 0.8% (w/w) for combined esters.
5.3 Pharmaceutical Industry
- Preservative in Pharmaceutical Preparations: In the pharmaceutical field, methylparaben is used as an antibacterial and antifungal agent in various pharmaceutical formulations. In liquid medications such as oral suspensions, syrups, and ophthalmic solutions, it prevents microbial growth, ensuring the sterility and stability of the product. In semi - solid preparations like ointments and creams, it helps to maintain the quality of the product by inhibiting the growth of microorganisms that could potentially contaminate the formulation.
- Compliance with Pharmaceutical Standards: Pharmaceutical products are subject to strict quality and safety regulations. Methylparaben used in pharmaceuticals must meet high - purity standards and comply with regulations set by regulatory bodies such as the European Pharmacopoeia (Ph. Eur.), the United States Pharmacopeia (USP), and the Japanese Pharmacopoeia (JP). These standards ensure that the methylparaben used in pharmaceutical products is free from impurities that could affect the safety and efficacy of the medication.
5.4 Other Applications
- Organic Synthesis Intermediate: Methylparaben can be used as an intermediate in organic synthesis reactions. It can participate in various chemical reactions to synthesize more complex organic compounds. For example, it can be further modified through esterification, substitution, or other reactions to obtain compounds with specific functional groups for use in the synthesis of pharmaceuticals, agrochemicals, or other fine chemicals.
- Film and Coating Industry: In the film and coating industry, methylparaben can be used as a preservative additive. For example, in some types of biodegradable films used in food packaging or in coatings applied to various surfaces, it can prevent the growth of microorganisms that could cause degradation of the film or coating over time, thus extending their service life.
6. Storage and Packaging
6.1 Storage Conditions
- Temperature and Humidity: Methylparaben should be stored in a cool, dry, and well - ventilated warehouse. The recommended storage temperature is generally below 25 °C. High temperatures can accelerate its decomposition or affect its stability. Relative humidity should be maintained at less than 60%. Excessive humidity can cause the absorption of moisture by methylparaben, which may lead to clumping or a decrease in its effectiveness.
- Avoidance of Contaminants: It should be stored away from strong oxidizing agents, strong acids, and strong bases, as these substances can react with methylparaben, altering its chemical properties. Additionally, it should be kept away from sources of ignition and heat sources to prevent the risk of fire or thermal decomposition. Under proper storage conditions, the shelf life of methylparaben is usually 2 - 3 years, but this may vary slightly depending on the specific manufacturing process and storage environment.
6.2 Packaging Forms
- Industrial - Scale Packaging: For large - scale industrial use, methylparaben is often packaged in cardboard drums lined with polyethylene plastic bags. Each drum typically has a net weight of 25 kg. This type of packaging provides good protection against moisture and physical damage during transportation and storage. Another common packaging option is plastic woven bags, which can hold 50 kg of the product. These bags are sturdy and suitable for bulk transportation.
- Small - Scale and Laboratory Packaging: For small - scale users or laboratory applications, methylparaben is available in smaller containers. It may be packaged in glass bottles or plastic cans with capacities such as 500 g or 1 kg. These smaller packages are convenient for research institutions, small - scale manufacturers, or for sample testing purposes. All packaging is clearly labeled with important information, including the product name, chemical formula, batch number, 生产日期 (production date), expiration date, storage instructions, and the name and contact information of the manufacturer, ensuring easy identification and traceability.
