Why Are Preservative Systems in Daily Chemical Products Effective? Common Types, Mechanisms of Action, and Factors Affecting Preservation Efficacy

1 The Fundamental Problem Preservatives Are Intended to Solve

1.1 Why Daily Chemical Products Undergo Microbial Spoilage

Microbial spoilage in daily chemical products essentially occurs when microorganisms find conditions in the product that are suitable for survival and reproduction. Microbial growth typically requires water, nutrient sources, a suitable temperature, and a source of contamination. Many daily chemical products naturally provide these conditions. For example, lotions, creams, gels, shampoos, shower gels, wet wipe liquids, and facial mask essences all contain an aqueous phase. Oils, sugars, polyols, botanical extracts, proteins, polysaccharides, amino acids, and certain surfactants in a formulation may also provide available nutrients or a favorable growth environment for microorganisms.

1.2 Preservatives Act on Microorganisms

The target of preservatives is the microorganisms present in the product. From a mechanistic perspective, preservatives mainly interfere with key life processes of microorganisms, such as cell membrane function, intracellular acid-base balance, enzyme systems, protein structure, and energy metabolism. As a result, microorganisms can no longer continue to grow, reproduce, or maintain normal metabolic activity.

The actual preservation effect of a preservative is usually determined by the combined influence of the following factors:

Molecular structure → Physicochemical properties → Site of action → Antimicrobial mechanism → Effective concentration in the formulation → Final preservation efficacy

2 How Preservatives Inhibit Microbial Life Activities

To maintain life activities, microorganisms require an intact cell membrane, stable intracellular pH, normal enzyme systems, stable protein structures, and continuous material transport and energy metabolism. Preservatives exert their effects by interfering with these key processes.

Microbial life activity	Preservative intervention	Possible result
Cell membrane integrity	Alters membrane permeability or disrupts membrane structure	Leakage of cellular contents and abnormal material transport
Intracellular pH stability	Causes intracellular acidification	Decreased enzyme activity and inhibited metabolism
Enzyme system activity	Reacts with active groups in enzymes	Interruption of key metabolic processes
Protein structure	Causes protein denaturation, cross-linking, or inactivation	Impaired cellular function
Aqueous growth environment	Reduces available water or strengthens the antimicrobial environment	Restricted microbial reproduction

3 Common Types of Antimicrobial Ingredients and Their Mechanisms of Action in Daily Chemical, Cosmetic, and Industrial Aqueous Systems

3.1 Acid-Stress Preservatives

Representative raw materials of acid-stress preservatives include benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, dehydroacetic acid, and their salts. The key to this type of preservative lies in the “undissociated acid” form. Undissociated acid molecules can more easily pass through microbial cell membranes. After entering the cell, they release hydrogen ions, causing intracellular acidification. Once the intracellular pH decreases, microbial enzyme activity, nutrient transport, and energy metabolism are disrupted, thereby reducing the ability of microorganisms to grow and reproduce.

This type of preservative is relatively sensitive to pH. At lower pH values, the proportion of undissociated acid is higher, making the preservation effect easier to achieve. As pH increases, more of the acid exists in ionic form, reducing its ability to pass through microbial cell membranes and weakening its preservation effect.

Category	Representative raw materials	Main characteristics	Selection focus
Benzoic acid derivatives	Benzoic acid, sodium benzoate	Commonly used in acidic or weakly acidic systems; inhibitory effect against yeasts and some bacteria	Pay close attention to final pH
Sorbic acid derivatives	Sorbic acid, potassium sorbate	Commonly used for mold and yeast control	More suitable for weakly acidic systems
Dehydroacetic acid derivatives	Dehydroacetic acid and its salts	Can be used in some cosmetic and daily chemical systems	Pay attention to regulatory limits and formulation compatibility

3.2 Cell Membrane-Disrupting Preservatives

Representative raw materials of cell membrane-disrupting preservatives include phenoxyethanol, benzyl alcohol, and certain cationic ingredients with antimicrobial activity. Microbial cell membranes are mainly composed of lipids and proteins and serve as key barriers for maintaining cell structure and material exchange. Some preservatives have appropriate lipophilicity, enabling them to enter or disrupt microbial cell membranes. This changes membrane permeability, leading to abnormal movement of ions, metabolites, and cellular contents, ultimately affecting normal cellular metabolism.

Phenoxyethanol is one of the commonly used preservatives in daily chemical formulations. Its molecular structure contains an aromatic ring and an ether-alcohol structure, giving it both a certain degree of lipophilicity and a certain ability to distribute in the aqueous phase. Therefore, it is widely used in shampoos, personal care washes, lotions, creams, wet wipes, and similar products. Phenoxyethanol is generally considered to affect microbial cell membrane function and cellular metabolic processes. In actual formulations, it is often combined with other preservatives or preservative boosters to broaden the antimicrobial spectrum and improve overall preservation efficacy.

Some quaternary ammonium ingredients with antimicrobial activity have cationic characteristics and can readily interact with negatively charged microbial cell surfaces, thereby affecting cell membrane structure. The antimicrobial activity of these ingredients is often related to the length of the alkyl chain. However, not all quaternary ammonium compounds are used as cosmetic preservatives. Their actual application should be assessed based on product attributes, regulatory requirements, and formulation compatibility.

3.3 Enzyme-Inactivating Antimicrobial Agents

Representative raw materials of enzyme-inactivating antimicrobial agents include methylisothiazolinone (MIT), methylchloroisothiazolinone/methylisothiazolinone blends (CMIT/MIT), benzisothiazolinone (BIT), octylisothiazolinone (OIT), and others. Among them, MIT and CMIT/MIT may be used as cosmetic preservatives in certain markets and specific product types, but they are subject to strict limits, product-type restrictions, and safety assessment requirements. BIT, OIT, and similar ingredients are more commonly used in industrial aqueous systems, coatings, material mildew prevention, and related research evaluations.

Isothiazolinone-type preservatives are characterized by high activity and low use levels. Their molecular structures contain reactive nitrogen-sulfur structures that can react with nucleophilic groups in microbial intracellular proteins or enzymes, especially key enzymes containing thiol groups, thereby interfering with microbial metabolic processes.

This type of preservative can be effective at low use levels because it does not merely change the external growth environment; rather, it directly affects key enzyme systems involved in microbial life activities. However, precisely because of their strong reactivity, isothiazolinone raw materials used in cosmetics require careful verification of applicable product types, maximum permitted concentrations, labeling requirements, and sensitization risks.

Category	Representative raw materials	Application characteristics	Key points to note
Isothiazolinones	MIT, CMIT/MIT, BIT, OIT	Highly active and used at low levels; commonly seen in industrial preservation systems and certain specific daily chemical systems	Focus on regulatory restrictions, sensitization risk, and product type
Chlorinated isothiazolinones	CMIT	Strong antimicrobial activity	Strictly confirm the applicable scope and permitted concentration

3.4 Protein-Reactive and Release-Type Preservatives

Representative raw materials of protein-reactive and release-type preservatives include DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, sodium hydroxymethylglycinate, and certain aldehyde preservatives.

This type of preservative can release small active molecules or directly react with active groups in microbial proteins and enzyme systems, damaging protein structure and function. Taking formaldehyde releasers as an example, their preservative effect is related to the formaldehyde they release. Formaldehyde can react with active groups in biological macromolecules such as proteins and nucleic acids, thereby disrupting microbial cell function.

These preservatives generally have strong preservation capability, but they are also more likely to be affected by regulatory concentration limits, applicable product types, labeling or warning statement requirements, irritation potential, sensitization potential, and consumer acceptance. Their release behavior may be influenced by pH, temperature, storage time, and the formulation matrix. Therefore, actual preservation efficacy and safety compliance cannot be judged solely on the basis of theoretical addition levels.

3.5 Ester Preservatives

Representative raw materials of ester preservatives include methylparaben, ethylparaben, propylparaben, and butylparaben. In the industry, these are commonly referred to as parabens.

These preservatives contain an aromatic ring and an ester group, and generally have good overall stability. They have inhibitory effects against molds, yeasts, and some bacteria. As the alkyl chain of the ester group becomes longer, molecular lipophilicity usually increases, and affinity for microbial membrane structures may also increase, while water solubility decreases. Therefore, different esters are often combined to balance solubility, antimicrobial spectrum, and formulation suitability.

Parabens have a long history of use and generally offer good stability and formulation adaptability. However, they also face certain consumer perception concerns. In actual selection, regulatory allowances, safety assessment, product type, and market positioning should all be taken into account.

3.6 Preservative-Boosting Auxiliary Ingredients

Representative raw materials of preservative-boosting auxiliary ingredients include ethylhexylglycerin, caprylyl glycol, glyceryl caprylate, 1,2-hexanediol, and 1,2-pentanediol.

These ingredients are not necessarily listed as traditional preservatives in regulatory preservative lists, but they are often used in modern daily chemical formulations to build preservative systems. Their functions typically include altering microbial cell membrane permeability, improving the distribution of preservatives within the formulation, enhancing the ability of the main preservative to enter microbial cells, and, at certain addition levels, helping to reduce the available water in the system. The value of these ingredients lies in improving the efficiency of the overall preservative system, allowing the formulation to achieve sufficient microbial control even at lower levels of traditional preservatives.

4 How Molecular Structure Affects Preservation Performance

4.1 Lipophilicity Affects the Ability to Act on Cell Membranes

Microbial cell membranes have lipid characteristics. If a preservative molecule has appropriate lipophilicity, it can more easily approach, enter, or disrupt the cell membrane. Structural features such as aromatic rings, alkyl chains, halogen substituents, and ester groups all affect molecular lipophilicity and membrane affinity.

However, stronger lipophilicity is not always better. Excessive lipophilicity may cause preservatives to distribute more into the oil phase, the interior of micelles, or packaging materials, resulting in a lower effective concentration in the aqueous phase. Since microorganisms mainly grow in the aqueous phase or at the oil-water interface, preservatives must maintain sufficient concentrations in these regions to exert their preservation effect.

4.2 Dissociation State Affects the Ability to Enter Cells

Organic acid preservatives illustrate how dissociation state affects preservation performance. Taking benzoic acid and sorbic acid as examples, it is the undissociated acid molecules that more readily pass through cell membranes. When the formulation pH is relatively low, the proportion of undissociated acid is higher, making it easier for the molecules to enter microbial cells. When pH increases, more of the acid exists in ionic form, reducing membrane permeability and weakening the preservation effect.

4.3 Reactive Groups Determine Reactivity

The action of isothiazolinones, aldehydes, formaldehyde releasers, and similar preservatives is related to reactive groups in their molecular structures. These groups can react with active sites in microbial intracellular proteins or enzymes, leading to impairment of key biological functions.

These preservatives are usually used at low levels and have strong activity, but they also require stricter evaluation of safety and irritation potential. Structures capable of reacting with microbial biological macromolecules may also interact unfavorably with human skin proteins, increasing the risk of sensitization or irritation.

4.4 Molecular Size, Solubility, and Partitioning Behavior Affect Effective Concentration

After a preservative is added to a formulation, this does not mean that all of it can exert an effect. The portion that actually works is the portion that can contact microorganisms and remain active. In daily chemical formulations, preservatives may undergo the following distribution or loss processes:

Influencing factor	Possible result
High oil-phase proportion	Preservative partitions into the oil phase, reducing its concentration in the aqueous phase
Large number of surfactant micelles	Preservative is encapsulated within micelles, reducing the free concentration
Presence of thickeners or powders	Preservative is adsorbed, reducing the effective concentration
Presence of high-molecular-weight polymers	Preservative binds or its distribution changes
Insufficient compatibility with packaging materials	Preservative is adsorbed by packaging or migrates into packaging
High temperature or long-term storage	Some preservatives degrade, volatilize, or show altered release behavior

Therefore, the amount of preservative added is not equivalent to the actual effective concentration. When assessing preservation efficacy, one should not only look at the addition percentage in the formula, but also consider the distribution, stability, and free effective concentration of the preservative in the formulation.

5 Why the Same Preservative Performs Differently in Different Formulations

5.1 pH Affects Preservative Activity and Stability

pH has a relatively obvious impact on organic acid preservatives, and it can also affect the stability, solubility, and formulation compatibility of some preservatives. In weakly acidic systems, organic acid salts, phenoxyethanol combinations, and multifunctional preservative-boosting systems may be considered. In near-neutral or alkaline systems, pH-sensitive preservatives such as sodium benzoate and potassium sorbate should not be relied upon as the sole preservation solution.

5.2 The Aqueous Phase Is the Key Site of Action for Preservative Systems

Microorganisms usually grow in aqueous environments. Therefore, preservatives need to maintain sufficient effective concentrations in the aqueous phase or at the oil-water interface. For lotions, creams, cleansing and hair care products, wet wipe liquids, and facial mask essences, the distribution of preservatives in the aqueous phase directly affects final preservation efficacy.

5.3 Surfactants, Oils, and Polymers Can Alter Preservative Distribution

In surfactant systems such as shampoos, shower gels, and facial cleansers, preservatives may enter the interior of micelles, leading to a decrease in free concentration. In lotions and creams, preservatives may redistribute among the oil phase, aqueous phase, and interface. In formulations containing powders, clays, fibers, natural gums, or polymeric thickeners, preservatives may be adsorbed or bound. Therefore, the same preservative at the same addition level may perform very differently in transparent aqueous solutions, lotions, creams, shampoos, and wet wipe liquids.

5.4 Initial Microbial Load of Raw Materials Increases Preservation Pressure

Preservatives cannot replace microbial control during production. If raw materials have a high initial microbial load, or if water systems, storage tanks, pipelines, or packaging materials are not adequately controlled, the preservative system will face greater pressure. Botanical extracts, fermentation products, proteins, polysaccharides, natural gums, powder dispersions, and reused containers may all introduce higher microbial risks. For such formulations, simply increasing the preservative dosage may not solve the problem. Raw materials, processes, equipment, and the production environment must be controlled at the same time.

5.5 Packaging and Usage Method Affect the Risk of Secondary Contamination

Different packaging formats carry different contamination risks. Jar packaging is more likely to be repeatedly contaminated by hands, tools, or air during use. Pump bottles, tubes, and single-use packaging can reduce the risk of secondary contamination. High-water-content products such as wet wipes and facial mask essences have large contact areas and therefore place higher requirements on the preservative system.

6 Differences Among Industrial-Grade, Cosmetic-Grade, and Food-Grade Preservatives

The differences among industrial-grade, cosmetic-grade, and food-grade preservatives mainly lie in their intended applications, quality control requirements, safety evaluation standards, and regulatory requirements.

Type	Main applications	Key concerns	Representative raw materials
Industrial-grade preservatives	Coatings, adhesives, cleaning agents, cutting fluids, water treatment, industrial aqueous systems	Antimicrobial efficiency, cost, system stability, material compatibility, occupational safety	BIT, OIT, CMIT/MIT, DBNPA, glutaraldehyde
Cosmetic-grade preservatives	Hair care and personal wash products, creams, lotions, wet wipes, color cosmetics, oral care, etc.	Skin-contact safety, irritation, sensitization, impurity control, regulatory limits	Phenoxyethanol, sodium benzoate, potassium sorbate, parabens, chlorphenesin, benzyl alcohol, etc.
Food-grade preservatives	Beverages, sauces, baked goods, dairy products, meat products, etc.	Ingestion safety, food category, maximum use level, residue control	Sodium benzoate, potassium sorbate, calcium propionate, natamycin, nisin

The same chemical substance may differ across grades in terms of purity, impurities, residual solvents, stabilizers, test items, and regulatory applicability. Food grade does not mean that a material can be directly used in cosmetics, and industrial grade also cannot be directly applied to products intended for human contact.

Cosmetic preservatives should be assessed in accordance with the Safety and Technical Standards for Cosmetics (2015 Edition) and subsequent amendments, including verification of permitted preservatives, maximum allowed concentrations, applicable scope, and labeling requirements. For cosmetics entering the EU market, permitted preservatives, concentration limits, and restrictions must also be checked according to Annex V of the EU Cosmetics Regulation, Regulation (EC) No 1223/2009. Food preservatives should be assessed according to food additive standards, such as GB 2760—2024, National Food Safety Standard: Standard for the Use of Food Additives, to confirm the permitted food categories, maximum use levels, and residue requirements.

7 Effects of Temperature and Summer Production on Preservative Systems

Rising temperature may lead to several changes:

① Faster microbial reproduction;

② Raw materials and semi-finished products become more susceptible to contamination;

③ Some preservatives may volatilize, degrade, or exhibit altered release behavior;

④ Formulation pH, viscosity, and emulsified structure may change;

⑤ Compatibility risks between packaging materials and contents may increase.

Summer production requires higher levels of microbial control rather than blindly increasing preservative dosage. Preservative dosage must comply with relevant regulatory limits. Excessive addition may increase the risk of irritation, sensitization, odor problems, and formulation instability. More reasonable control measures for summer production include:

Control point	Key measures
Water system	Strengthen water quality monitoring, pipeline cleaning, and microbial control
Raw materials	Control the microbial load of high-risk raw materials and shorten storage time after opening
Process	Reduce exposure time of semi-finished products and control contamination during cooling and filling
Equipment	Strengthen cleaning, disinfection, and inspection of dead zones
Packaging	Confirm packaging cleanliness and sealing performance
Formulation	Recheck pH, viscosity, compatibility, and the effective preservative concentration
Verification	Confirm the preservative system through challenge testing and stability testing

If products manufactured in summer show bottle swelling, unusual odor, mold spots, phase separation, or microbial levels exceeding limits, the first step should be to investigate raw materials, the water system, production hygiene, packaging contamination, pH drift, and preservative inactivation. Only after these causes have been evaluated should the preservative system be optimized within the scope allowed by regulations.

8 Classification Table of Representative Chemicals Related to Preservatives and Preservative Boosters

Table 1 Acid-Type Preservatives and Related Organic Acids/Salts

Category	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Benzoic acid-type organic acid salt	532-32-1	S104124	Sodium benzoate	AR, ≥99%	Used for preservation experiments in acidic formulations, studies on the antimicrobial activity of undissociated acids, and evaluation of benzoate-based combination systems
Benzoic acid-type organic acid	65-85-0	B433248	Benzoic acid	Suitable for synthesis	Used for studies on the preservation mechanism of organic acids, experiments on the effect of pH on antimicrobial efficacy, and development of benzoate-based systems
Sorbic acid-type organic acid	110-44-1	S101106	Sorbic acid	AR, ≥99%	Used for research on mold and yeast control, development of weakly acidic preservative systems, and organic acid antimicrobial experiments
Sorbic acid-type organic acid salt	24634-61-5	P103845	Potassium sorbate	≥99% (T)	Used for preservation in weakly acidic daily chemical formulations, evaluation of sorbate-based combination systems, and mold and yeast control experiments
Propionic acid-type organic acid	79-09-4	P434195	Propionic acid	Suitable for synthesis	Used for propionate synthesis research, organic acid preservation model experiments, and mold inhibition-related studies
Propionic acid-type organic acid salt	4075-81-4	C492256	Calcium propionate	≥99% (in dried substance)	Used for propionate preservation research, food preservation model experiments, and mold control evaluation
Dehydroacetic acid-type organic acid salt	4418-26-2	D170376	Sodium dehydroacetate	≥99% (T)	Used for research on dehydroacetate preservative systems, antimicrobial evaluation of daily chemical formulations, and preservation experiments in acidic systems
Dehydroacetic acid-type organic acid	520-45-6	D106379	Dehydroacetic acid	≥98%	Used for studies on the preservation mechanism of dehydroacetic acid derivatives, mold and yeast control experiments, and development of cosmetic preservative systems
Salicylic acid-type organic acid	69-72-7	S1507096	Salicylic acid	Electronic grade, Moligand™, ≥99.5%	Used for acidic formulation research, keratin-conditioning-related experiments, and evaluation of preservation synergy and pH effects
Levulinic acid-type organic acid	123-76-2	L104281	Levulinic acid	AR, Moligand™, ≥99%	Used for research on preservative-boosting systems, development of weakly acidic formulations, and application experiments involving multifunctional organic acids
Levulinic acid-type organic acid salt	19856-23-6	S769986	Sodium levulinate	≥98%	Used for weak-acid salt formulation research, preservative-boosting experiments, and evaluation of mild combination preservative systems
Aromatic organic acid	100-09-4	M104368	p-Anisic acid	≥98%	Used for research on preservative boosting with aromatic acids, development of weakly acidic systems, and studies on fragrance-preservation synergy

Table 2 Parabens and Their Sodium Salts

Category	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Sodium methylparaben	5026-62-0	M102796	Sodium methylparaben	≥99%	Used for research on water-soluble paraben systems, solubility experiments of ester preservatives, and validation of combination preservative systems
Ethylparaben	120-47-8	E105141	Ethylparaben	Chemically pure (CP), ≥99%	Used for studies on the antimicrobial spectrum of ester preservatives, development of cosmetic preservative systems, and experiments on the influence of ester-chain structure
Butylparaben	94-26-8	B108966	Butylparaben	≥99%	Used for research on long-chain ester preservatives, oil-water partitioning experiments, and evaluation of compound preservative systems
Propylparaben	94-13-3	P105152	Propylparaben	≥99% (GC)	Used for research on paraben-based preservative formulations, anti-mold and anti-yeast experiments, and ester preservative combination applications
Methylparaben	99-76-3	M108620	Methylparaben	AR, Moligand™, ≥99%	Used for research on classic ester preservatives, basic preservative model experiments, and validation of cosmetic preservative formulations
Sodium propylparaben	35285-69-9	P101304	Sodium propylparaben	PharmPure™, USP, European Pharmacopoeia (Ph. Eur.)	Used for research on water-soluble propylparaben salts, development of paraben combination systems, and pharmacopoeial-grade preservation-related experiments

Table 3 Alcohols, Hydroxamic Acids, Polyols, and Chelating Boosters

Category	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Aromatic alcohol preservative	100-51-6	B108203	Benzyl alcohol	ACS, ≥99%	Used for research on aromatic alcohol preservatives, evaluation of microbial control in fragrance systems, and experiments on cell membrane disruption mechanisms
Aromatic alcohol preservative booster	60-12-8	P108197	2-Phenylethanol	≥99% (GC)	Used for research on the antimicrobial activity of aromatic alcohols, preservative-boosting experiments in fragrance-based formulations, and development of combination preservative systems
Chlorinated aromatic alcohol preservative	104-29-0	C131938	3-(4-Chlorophenoxy)-1,2-propanediol	≥99%	Used for research on chlorphenesin-type preservatives, preservation validation of personal care formulations, and membrane-action-related experiments
Phenoxy alcohol preservative	122-99-6	E109370	2-Phenoxyethanol	≥99%	Used for research on phenoxyethanol preservative systems, combination preservation experiments in daily chemical formulations, and evaluation of cell membrane action mechanisms
Hydroxamic acid preservative booster	7377-03-9	O123988	Caprylhydroxamic acid	≥99%	Used for research on hydroxamic acid preservative boosters, development of low-irritation preservative systems, and mold control experiments
Glyceryl ester preservative booster	26402-26-6	M1516128	Glyceryl monocaprylate (GMC)	≥98%, monoacylglycerol + diacylglycerol + triacylglycerol	Used for research on glyceryl ester preservative boosters, antimicrobial experiments in emulsified systems, and evaluation of effects on membrane permeability
Ether glycol preservative booster	70445-33-9	E156476	3-(2-Ethylhexyloxy)-1,2-propanediol	≥98% (GC)	Used for research on ethylhexylglycerin preservative boosting, phenoxyethanol combination experiments, and development of mild preservative systems
Short-chain diol preservative booster	6920-22-5	H108067	1,2-Hexanediol	≥98%	Used for research on polyol preservative boosting, moisturizing-preservation synergistic formulations, and experiments on changes in available water
Short-chain diol preservative booster	5343-92-0	P108068	1,2-Pentanediol	≥98%	Used for polyol preservative-boosting experiments, research on transparent aqueous systems and emulsions, and moisturizing synergy applications
Long-chain diol preservative booster	1117-86-8	O108069	1,2-Octanediol	≥96%	Used for research on caprylyl glycol preservative boosting, development of combination preservative systems, and cell membrane permeability experiments
Amidine antimicrobial preservative	659-40-5	H709121	Hexamidine diisethionate	≥98%	Used for research on amidine antimicrobial activity, evaluation of microbial control in personal care formulations, and preservative synergy experiments
Chelating booster	139-33-3	D684233	Disodium ethylenediaminetetraacetate	≥99%	Used for metal ion chelation research, preservative system stability experiments, and auxiliary evaluation in formulation challenge testing

Table 4 Isothiazolinones and Iodopropynyl Carbamate Antimicrobial Research Ingredients

Category	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Benzisothiazolinone preservative	2634-33-5	B598939	1,2-Benzisothiazol-3(2H)-one	≥99%, metal <3000 ppm	Used for preservation research in industrial aqueous systems, enzyme inactivation mechanism experiments, and coating preservation evaluation
Methylchloroisothiazolinone blend	26172-55-4	C183242	Isothiazolinone CMI/MI	Mixture of CMI and MI, 2.0–2.5% in water, pH: 2.0–5.0	Used for research on isothiazolinone combination preservation, preservation evaluation of rinse-off systems, and industrial preservation experiments
Methylchloroisothiazolinone mixture	55965-84-9	M193940	Isothiazolinone	14% in H2O	Used for preservation experiments in aqueous products, research on isothiazolinone combinations, and verification of enzyme inactivation mechanisms
Dichlorooctylisothiazolinone mildewcide	64359-81-5	D155452	4,5-Dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT)	≥98% (GC)	Used for material mildew-prevention research, coating preservation and mildew-prevention experiments, and structure-activity analysis of isothiazolinones
Octylisothiazolinone mildewcide	26530-20-1	O107425	2-Octyl-4-isothiazolin-3-one (OIT)	≥98%	Used for industrial mildew-prevention and preservation research, paint and coating system experiments, and evaluation of the effect of lipophilicity on preservation efficacy
Iodopropynyl carbamate mildewcide	55406-53-6	I107478	3-Iodo-2-propynyl N-butylcarbamate	≥97%	Used for mildewcide research, mildew-prevention evaluation in wet wipes and coatings, and iodopropynyl carbamate application experiments
Methylisothiazolinone preservative	2682-20-4	M110103	2-Methyl-4-isothiazolin-3-one (MIT)	≥95%	Used for research on isothiazolinone monomers, experiments on enzyme-inactivation preservation mechanisms, and safety evaluation of formulation preservation

Table 5 Aldehydes, Release-Type Preservatives, Halogenated Preservatives, and Industrial Biocides

Category	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Aldehyde reactive industrial preservative	111-30-8	G105908	Glutaraldehyde (50%)	Photographic grade, 50% in H2O	Used for research on aldehyde cross-linking and industrial preservation, protein reaction mechanism experiments, and water treatment biocidal evaluation
Phosphonium salt industrial biocide	55566-30-8	B101527	Tetrakis(hydroxymethyl)phosphonium sulfate (THPS)	75% aqueous solution	Used for industrial water treatment biocide research, microbial control in oilfield water systems, and experiments on reducing biocidal systems
Halogenated cyanoamide rapid biocide	10222-01-2	D154876	2,2-Dibromo-2-cyanoacetamide	≥98%	Used for research on rapid-acting industrial preservation, circulating water and papermaking water system experiments, and activity evaluation of halogenated amides
Formaldehyde-releasing urea preservative	39236-46-9	I133416	Imidazolidinyl urea	≥98%	Used for research on release-type preservatives, validation of cosmetic preservative systems, and experiments on protein-reactive preservation mechanisms
Bronopol preservative	52-51-7	B114888	Bronopol	≥98%	Used for research on halogenated alcohol preservatives, development of daily chemical preservative systems, and bacterial control experiments
Formaldehyde-releasing urea preservative	78491-02-8	D136733	Diazolidinyl urea	≥98%	Used for research on release-type preservative systems, preservation evaluation of creams and lotions, and storage stability experiments
Formaldehyde-releasing hydantoin preservative	6440-58-0	B194375	1,3-Dimethylol-5,5-dimethylhydantoin	≥95%	Used for DMDM hydantoin preservation research, experiments on release-type preservation mechanisms, and validation of preservation in daily chemical formulations
Formaldehyde-releasing amino acid salt preservative	70161-44-3	S698473	Sodium N-(hydroxymethyl)glycinate	≥95%	Used for research on release-type preservatives, formulation preservation experiments, and evaluation of pH and temperature effects

Table 6 Cationic Quaternary Ammonium Antimicrobial/Antibacterial Research Ingredients

Category	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Benzyldimethylalkylammonium salts	63449-41-2	B103604	Alkylbenzyldimethylammonium chloride	Pharmaceutical grade, PharmPure™, ≥95%	Used for research on cationic antimicrobial agents, membrane disruption mechanism experiments, and evaluation of cleaning and disinfection-related formulations
Benzalkonium chloride quaternary ammonium mixture	8001-54-5	A494099	Benzalkonium chloride	80% ethanol solution	Used for research on quaternary ammonium antimicrobials, development of surfactant-based antimicrobial systems, and experiments on membrane permeability effects
Alkyltrimethylammonium salts	112-02-7	H105309	Hexadecyltrimethylammonium chloride (CTAC)	≥97%	Used for research on cationic surfactants, cell membrane action models, and antimicrobial wash-care formulation experiments
Pyridinium quaternary ammonium salts	123-03-5	C129534	Cetylpyridinium chloride	≥98%	Used for oral care antimicrobial research, development of cationic antimicrobial formulations, and evaluation of membrane action mechanisms
Double-chain quaternary ammonium salts	7173-51-5	N194743	Didecyldimethylammonium chloride (DDAC)	≥95%	Used for research on double-chain quaternary ammonium antimicrobials, hard-surface cleaning system experiments, and industrial microbial control evaluation

Note: The above are representative Aladdin products for scientific research, method development, mechanism studies, formulation screening, and industrial system evaluation. Whether they can be used in cosmetics, food products, wet wipes, oral care products, infant and child products, or other finished products intended for human contact should be determined based on product grade, COA/specifications, intended-use statements, target-market regulations, finished-product safety assessment, and challenge test results. For more product specifications, grades, and COA information, search by “product name/CAS/catalog number” on the Aladdin website.

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CTAB Demystified: Structure, Properties, and Practical Uses of a Classic Cationic Surfactant

Poloxamers Explained: A Comprehensive Guide to Non-Ionic Block Copolymer Surfactants

Non-Ionic Surfactants in Focus: Alcohol Ethoxylates, Polyethylene Glycol Trimethylnonyl Ether, and Triton™ X-100

Tween 20 and Tween 80 as Non-Ionic Surfactants: Structure, Properties, and Applications

A Panoramic Guide to Surfactants: Definitions & Mechanisms, Key Metrics, Application Scenarios, and Selection Navigation (Tables 1–3)

Saponins as Natural Non-ionic Surfactants: Structure, Function, and Applications

Non-ionic Detergents Explained: From Chemical Structure to Laboratory Use

Practical Guide to Sodium Carboxymethyl Cellulose (CMC-Na): Thickening/Stabilizing Mechanisms, Key Controls for Solution Preparation, and Selection Navigation (including Table 1 and Tables A–C)

Alcohol Ethoxylates (AEO) Explained: Structure, Key Parameters, Application Scenarios, and Aladdin’s Selection Tables (Main + Appendix)