Aolong Chemical Product Knowledge

Sodium benzoate is available as powder, granules and Columnar products. Choosing a form means matching its physical characteristics to the way a plant stores, transfers, measures, mixes and dissolves the material. Particle size, shape and handling behavior all deserve attention alongside chemical specifications.

This guide explains the three solid forms in Aolong Chemical's sodium benzoate range and the information that helps buyers and production teams compare them. A useful selection starts with a clear product description and is confirmed by a trial under the intended operating conditions.

The chemical identity behind the different forms

Sodium benzoate is the sodium salt of benzoic acid, with the chemical formula C₇H₅NaO₂ and CAS number 532-32-1. The JECFA specification describes its appearance broadly as white crystalline powder, flakes or granules. These are physical descriptions of the material. [1]

The form name alone does not establish purity, an applicable quality grade or the presence or absence of processing aids. Buyers should agree the chemical specification separately and check the relevant technical data sheet and batch certificate of analysis. Products in different forms can be assessed against the same agreed chemical requirements.

The three solid forms

Powder consists of fine particles. The word does not define a particular particle size or a narrow size distribution. Two powders may differ in their proportion of very fine material and in the amount of agglomeration, so a representative sample and a stated measurement method are more informative than the name alone.

Granular sodium benzoate is supplied as discrete granules, generally coarser than powder. The label does not specify a single particle size, a perfectly spherical shape or a particular manufacturing process. A purchasing specification should describe the actual size distribution and any relevant shape requirements.

Columnar sodium benzoate describes short cylindrical particles. Aolong Chemical uses Columnar as its established product designation. Its published Columnar TDS gives a diameter of 1.5 mm and a length of 2–4 mm. These are product-specific dimensions to confirm in the purchasing specification. Representative photographs or agreed image measurements help describe the actual material. [2]

In general terminology, cylindrical particles can also be described as granules. In this article, Granular and Columnar distinguish the conventional granular product and the cylindrical product in Aolong Chemical's range. They are commercial form descriptions, rather than a universal classification system.

How to compare particle size

A particle size result needs a method and a reporting basis. For sieve analysis, specify the aperture in micrometres or millimetres, the sieve standard and the percentage passing or retained. A mesh number on its own leaves the requirement incomplete.

Shape matters when interpreting the result. USP General Chapter 786 explains that woven-sieve classification primarily reflects a particle's breadth or width. A sieve result therefore does not fully describe the length of a Columnar particle. Direct measurements of diameter and length can complement the sieve distribution. [3]

Laser diffraction provides a different kind of size result. ISO 13320 explains that its optical model assumes spherical particles, so results for non-spherical material can differ from those obtained by sieving. Compare methods and distribution bases before treating two reported size values as equivalent. [4]

Material handling and dosing

Bag emptying, hopper discharge and feeder operation are practical places to compare forms. During a trial, record whether material discharges consistently, whether bridging occurs and how much mass the feeder delivers over a defined interval. Use the equipment and operating conditions that matter to the plant.

Flowability has several aspects. USP General Chapter 1174 notes that a single simple test cannot adequately characterize powder flow. A laboratory result is useful when its method is stated and its relationship to the intended operation is understood. [5]

Dust should also be assessed under representative handling conditions. Ask how the fine fraction is defined and measured, and check samples after normal transport or transfer if particle breakage is relevant. A coarse-looking sample alone does not establish a dusting performance claim.

Bulk density describes the mass occupying a bulk volume, including the spaces between particles. Particle packing therefore contributes to the result. [6] A volumetric feeder should be checked when a form or its bulk density changes, because a fixed delivered volume may contain a different mass. A dosing trial can establish the appropriate settings.

Solubility and dissolution time

Solubility describes how much material can dissolve under specified conditions. Dissolution time describes how quickly a particular sample enters solution. JECFA identifies sodium benzoate as freely soluble in water, but that description does not rank the dissolution time of commercial forms. [1]

Smaller particles offer more geometric surface area per unit mass when shape and density are otherwise comparable. Their actual dissolution behavior also depends on wetting, agglomeration, particle structure and mixing. These considerations give reasons to test a sample; they do not establish that one commercial form always dissolves fastest.

For a useful comparison, keep water quality, temperature, vessel geometry, mixing conditions, addition procedure and target final concentration the same. Account for assay and moisture when defining an equal active-ingredient addition. State the endpoint and repeat the trial to check consistency. Where dissolved concentration is critical, use an appropriate analytical measurement alongside visual observation.

Selecting a form for the production process

For a liquid premix, compare how reliably each sample reaches the required dissolved concentration within the available preparation time. Include weighing, transfer and vessel residue in the assessment, since these operations also affect the work required to prepare a batch.

For a dry blend, evaluate distribution in the actual mixture and check representative samples after the transfers that follow mixing. The size and handling properties of the other ingredients should be considered alongside those of sodium benzoate. A visual impression of a well-mixed sample is insufficient to establish uniform distribution.

For automated feeding, assess discharge stability, delivered mass and the frequency of operator intervention. A form that works in one hopper or feeder should be confirmed on the equipment intended for production. Keep the comparison focused on the plant's actual requirements.

Connecting form selection with preservation performance

The physical form label alone cannot establish preservation performance. In an original study of osmotolerant yeasts, Jermini and Schmidt-Lorenz examined sodium benzoate under different formulation conditions and found that factors including pH and initial contamination affected activity. This illustrates why results must be interpreted with their experimental conditions. [7]

A comparison of forms in a finished product should control the amount of active sodium benzoate and confirm adequate dissolution or distribution. Preservation performance then needs to be evaluated in the intended formulation and process. Appearance and particle shape provide useful handling information, while a preservation claim requires relevant application data.

Information to agree before ordering

A clear enquiry should identify the intended application, the required chemical specification and the preferred form. It should also state the physical properties that matter to the process. Useful supporting information includes:

• A form-specific technical data sheet and representative product photographs.

• Particle size requirements with the measurement method; diameter and length where relevant for Columnar products.

• Assay basis, moisture or loss on drying method, and bulk density method where these affect acceptance or dosing.

• Agreed handling or dissolution trial conditions, packaging and storage instructions, and a batch certificate of analysis.

Aolong Chemical supplies sodium benzoate in Powder, Granular and Columnar forms. The corresponding technical data sheets and representative samples provide a starting point for discussing specifications and arranging a process trial. [2]

Sources and further reading

Reference links checked on 29 October 2026

[1] FAO and WHO JECFA Sodium Benzoate specification

Prepared at the 46th JECFA in 1996; metals and arsenic specifications revised at the 63rd JECFA in 2004. Used here for chemical identity, broad physical descriptions and qualitative water solubility.

JECFA specification

[2] Aolong Chemical sodium benzoate technical data sheets

Used here to establish the Powder, Granular and Columnar product designations. These documents are product information, not a controlled comparative performance study.

Powder TDS

Granular TDS

Columnar TDS

[3] United States Pharmacopeia General Chapter 786

Particle Size Distribution Estimation by Analytical Sieving. USP-NF, 2022. The publicly accessible preview explains the relationship between sieve classification and particle breadth or width.

Official USP preview and DOI

[4] ISO 13320 2020

Particle size analysis — Laser diffraction methods. The official scope explains the spherical optical model and differences between sizing methods for non-spherical particles.

Official ISO scope

[5] United States Pharmacopeia General Chapter 1174

Powder Flow. USP-NF, 2023. Used for the limitation of relying on a single simple flow test. Publicly accessible chapter preview.

Official USP preview and DOI

[6] United States Pharmacopeia General Chapter 616

Bulk Density of Powders. USP-NF, 2024. Used for the definition of bulk density and the contribution of interparticle voids. Publicly accessible chapter preview.

Official USP preview and DOI

[7] Jermini M F G and Schmidt Lorenz W 1987

Activity of Na-Benzoate and Ethyl-Paraben Against Osmotolerant Yeasts at Different Water Activity Values. Journal of Food Protection, volume 50, issue 11. DOI 10.4315/0362-028X-50.11.920. Used for the qualitative influence of formulation conditions and initial contamination; the study does not compare the three commercial forms.

Original study DOI

Indexed study abstract