4-Hydroxybenzoic Acid 98%

The parent acid of the parabens, 4-hydroxybenzoic acid is isolated here from the leaf of Camellia sinensis by ethanol extraction and purification. It is the simplest hydroxylated benzoic acid, with one hydroxyl para to the carboxyl, and it is a slightly water soluble, off-white powder.

The primary grade is 98% 4-hydroxybenzoic acid by HPLC, in Food / Dietary Supplement Grade. The compound is not an ester and not a preservative as supplied, and its identity is settled by the single hydroxyl in the para position, which a catalog name should state in full.

SKU: BOT-PHY-0049 Category: Phytochemicals Tags: Dry Blends & Premixes, Ethanol Extracted, Leaf & Herb, Plant Compounds, Polyphenols, Tea

4-Hydroxybenzoic Acid Chemical Identity

4-Hydroxybenzoic acid has the molecular formula C7H6O3 and the molecular weight 138.1. A benzene ring carries a carboxylic acid group and, directly opposite it, a single phenolic hydroxyl. There is no catechol and no ortho hydroxyl to hydrogen-bond with the acid, so 4-hydroxybenzoic acid is more stable toward oxidation than the dihydroxybenzoic acids and has no tendency to decarboxylate under mild heat. The two functional groups sit in a rigid, linear arrangement that packs well in the crystal and keeps the melting point high and the water solubility modest.

The paraben preservatives are esters of this acid with alcohols such as methanol, ethanol or propanol, and the free acid is their precursor and a degradation product. A buyer who sees the name in a regulatory context should confirm that the product is the free acid. The natural source here is the leaf of Camellia sinensis (L.) Kuntze, where the acid occurs as a minor phenolic beside catechins and flavonols, and it is also widely distributed in other plants and made industrially from phenol. Tea also comes as Green Tea Extract 40–98% Polyphenols, Black Tea Extract 10–40% Theaflavins and the 10:1 Green Tea Extract Powder. Those materials are rich in catechins and flavonols, while 4-hydroxybenzoic acid is a small, simple molecule with no sugar attached and no catechol ring.

Typical Specifications

Specification Item	Product Information
Natural Source	Camellia sinensis leaf
Plant Part	Leaf & Herb
Processing	Ethanol Extraction & Purification
Compound Class	Polyphenols
Chemical Name (IUPAC)	4-hydroxybenzoic acid
CAS Number	99-96-7
Molecular Formula	C7H6O3
Molecular Weight	138.12
PubChem CID	135
InChIKey	FJKROLUGYXJWQN-UHFFFAOYSA-N
SMILES	C1=CC(=CC=C1C(=O)O)O
Purity	98% (HPLC)
Grade	Food / Dietary Supplement Grade
Appearance	Off-White powder
Solubility / Dispersibility	Slightly Soluble in Water
Quality Parameters
Moisture (LOD)	≤5.0%
Total Ash	≤5.0%
Heavy Metals	Lead ≤2 ppm · Arsenic ≤1 ppm · Cadmium ≤1 ppm · Mercury ≤0.1 ppm
Microbiology	TPC ≤1,000 cfu/g · Yeast & Mold ≤100 cfu/g · E. coli Negative · Salmonella Negative/25 g
Shelf Life	24 months in unopened original packaging, cool and dry storage

4-Hydroxybenzoic Acid Purity Grades & Impurities

The 98% figure is an HPLC result that compares the 4-hydroxybenzoic acid peak with the other detected peaks, with detection near 255 nm where the hydroxybenzoate chromophore absorbs. The figure does not count water, ash or components that fail to absorb, which is why the table limits moisture and ash separately. The product has a single grade.

The related substances of tea-derived 4-hydroxybenzoic acid are the other phenolic acids of the leaf. Gallic acid, protocatechuic acid, vanillic acid and p-coumaric acid are the neighbors, and they differ clearly in retention, so a standard gradient separates them. The more demanding impurities are positional isomers of hydroxybenzoic acid, namely salicylic acid, which is the 2-hydroxy form, and 3-hydroxybenzoic acid, and a method must show that neither is present at a significant level. Salicylic acid is a close neighbor on a reversed-phase column.

Esters of the acid can occur as trace products when an alcohol is used in extraction and purification. Ethyl and methyl 4-hydroxybenzoate are the parabens themselves, and their presence would change the character of the product, so the chromatogram is read at their retention times. A white to off-white powder shows a clean lot. Because the molecule has no catechol, color change is slow, and a yellow or tan tone usually points to residual tea pigment rather than to oxidation.

Plant-derived and synthetic 4-hydroxybenzoic acid share the same main peak. A buyer can tell which route a lot took by reading the stated source with the impurity profile.

4-Hydroxybenzoic Acid Solubility & Delivery

4-Hydroxybenzoic acid is slightly soluble in cold water and considerably more soluble in hot water. It dissolves in ethanol, methanol, acetone and ethyl acetate, and it is almost insoluble in nonpolar solvents. As a weak acid, it dissolves much better as the carboxylate, so a mildly alkaline stock dissolves it quickly, although the free acid is what this product supplies.

For delivery of 4-hydroxybenzoic acid, the main variable is temperature and pH. A warm solution carries more 4-hydroxybenzoic acid, and a hot solution that is cooled can deposit fine needle crystals, which clog nozzles or give a gritty mouthfeel in a clear drink. Because the molecule is stable, it tolerates heat steps, light and storage well compared with catechol acids. In dry blends the powder is free flowing and not very hygroscopic, though a fine grade carries static charge, and a premix with a dry carrier gives accurate small weights. Contact with iron is not a problem, since there is no catechol to form colored complexes.

Application Areas

Capsule Fills of the Free Acid

Capsules take 4-hydroxybenzoic acid at low to moderate inclusion. The crystalline powder flows adequately, though static clings to scoops, so anti-static tools and a sieved premix give an even fill weight with little loss to equipment.

Hot-Dissolved Drink Concentrates

Concentrates dissolve 4-hydroxybenzoic acid in hot water and are filled warm. Cooling can bring needle crystals out of solution, so the concentrate is held at the filling temperature or diluted to a level below saturation, and a cold-storage check follows.

Free-Flowing Stick Premixes

Sticks hold 4-hydroxybenzoic acid in a dry premix with sweetener and fruit acid. The powder is stable and flows well, so a short blend and a sieve are enough, and the pack needs only ordinary moisture protection.

Phenolic Acid Reference Blends

Analytical teams build mixtures of hydroxybenzoic acids to verify that a method separates the 2-, 3- and 4-hydroxy isomers. Each acid is weighed on its own, and a retained sample from each lot keeps a record of purity and retention time.

Ingredient Identity Checks

Quality teams that buy paraben-related materials use the free acid as an identity control. A sample is run beside the ester to confirm that the two are resolved and that the product here is the acid and not the preservative.

Packaging & Commercial Supply

Essencefield supports product evaluation, formulation trials, commercial orders, and ongoing ingredient supply. Packaging, storage, and shipping arrangements are determined by product characteristics, order quantity, stability requirements, and destination-market needs.

Supply Item	General Information
Sample	Available upon request for formulation, testing, and supplier evaluation
Order Quantities	100 g · 1 kg · 5 kg · 25 kg · 100 kg · 500 kg · Bulk
Sample Lead Time	Typically 5–7 days after sample confirmation
Production Lead Time	Typically 15–30 days after order and specification confirmation
Packaging	Suitable protective inner packaging with bags, cartons, drums, or other appropriate outer packaging
Storage	Store in tightly sealed, suitable protective packaging in a cool, dry environment. Protect from moisture, heat, and direct sunlight. Specific storage conditions follow the approved product specification.
Documentation	COA · Product Specification · TDS · SDS · Applicable declarations (as applicable)

Final order quantities, lead times, packaging, documentation, and shipping arrangements are confirmed according to the selected product and commercial requirements.