How Can Sodium Tripolyphosphate (STPP) Be Replaced? From Detergency Mechanisms to Formulation Choices for Low-Phosphorus/Phosphorus-Free Builder Systems

1. What Problems Does Sodium Tripolyphosphate Solve in Formulations?

Sodium tripolyphosphate (STPP) is a classic phosphate-based builder used in household and industrial cleaning formulations. It is commonly found in laundry powders, powdered cleaners, and some industrial cleaning systems. The core value of sodium tripolyphosphate is that it improves the conditions under which surfactants can function, making the overall cleaning system more stable and more effective.

In actual washing processes, hard-water ions such as Ca²⁺ and Mg²⁺ in water can consume anionic surfactants, form soap scum or inorganic deposits, and reduce detergency. After soils are detached from fabrics or hard surfaces, they may redeposit if they cannot remain stably dispersed in the washing liquor. The removal of oils, sebum, and particulate soils also requires a suitable alkaline environment. Sodium tripolyphosphate provides comprehensive builder performance by complexing hard-water ions, improving the effective utilization of surfactants, helping disperse soils, participating in pH adjustment, and adapting well to powder-processing systems.

2. What Is STPP: Names, Structure, and Formulation-Relevant Properties

2.1 Name and Abbreviation

Sodium tripolyphosphate, abbreviated as STPP, is also known as pentasodium tripolyphosphate. Its chemical formula is Na₅P₃O₁₀. Because the molecule contains five sodium ions, it is sometimes informally referred to in the industry as “pentasodium.” From a chemical-structure perspective, sodium tripolyphosphate belongs to the class of condensed phosphates. Its molecule contains multiple negatively charged phosphate oxygen groups, which can form complexes with metal ions such as Ca²⁺ and Mg²⁺. This structural feature is an important basis for the hard-water control and detergency-building effects of STPP.

 

2.2 Physicochemical Properties Relevant to Cleaning Formulations

Formulation-Relevant Property	Significance in Cleaning Applications
White powder or granular inorganic salt	Suitable for solid systems such as laundry powders, powdered cleaners, and tablets
Certain degree of water solubility	Can participate in metal-ion complexation in the washing liquor
Alkaline aqueous solution	Helps maintain a suitable washing pH
Condensed phosphate structure	Can complex hard-water ions such as calcium and magnesium
Phosphorus-containing builder	May increase the total phosphorus load in wastewater after use
Good compatibility with powder systems	Beneficial for powder processing, storage, and formulation-structure design

3. What Problems Does STPP Solve in Detergent Systems?

3.1 Controlling Hard-Water Ions and Reducing Surfactant Loss

Washing water often contains hard-water ions such as Ca²⁺ and Mg²⁺. These ions can react with anionic surfactants or fatty acid soaps to form insoluble salts, preventing surfactants from being fully available for soil removal. The main impacts of hard-water ions include:

Impact	Specific Manifestation
Reduced effective surfactant concentration	Surfactants are consumed by calcium and magnesium ions
Formation of soap scum or deposits	Fabrics become gray and stiff; residues appear on hard surfaces
Effects on foam and rinsing	Foam becomes unstable, and rinsing residues increase
Reduced formulation stability	The same product performs differently under different water-hardness conditions

STPP can form soluble complexes with hard-water ions such as Ca²⁺ and Mg²⁺, reducing the concentration of free calcium and magnesium ions in the washing liquor. This reduces the consumption of surfactants by hard-water ions and allows surfactants to more effectively perform wetting, emulsification, dispersion, and soil-removal functions.

3.2 Dispersing Soils and Reducing Redeposition

Cleaning does not end once soils are detached from a surface. If removed soils cannot remain stably dispersed in the washing liquor, they may reattach to fabric fibers or hard surfaces, causing fabric graying, reduced whiteness, scale residues, or surface haze. By controlling calcium and magnesium ions, STPP reduces the formation of metal-ion bridges among soil particles, fabric fibers, and inorganic deposits, thereby lowering the likelihood of soil redeposition.

3.3 Participating in pH Adjustment and Improving Cleaning Conditions

Many everyday soils, including sebum, oils, food residues, and particulate soils, are more easily emulsified, saponified, dispersed, or detached under mildly alkaline conditions. STPP aqueous solutions are alkaline and can help maintain the pH of the detergent system. However, STPP is not the main alkaline source in powdered detergents. In traditional laundry powders, the main alkalinity is usually provided jointly by ingredients such as sodium carbonate and sodium silicate. STPP plays more of a synergistic role in complexation, buffering, and detergency building.

3.4 Suitability for Powder Processing and Storage

STPP also has good processing compatibility in powder systems. It can contribute to the particle structure, flowability, moisture-absorption control, and storage stability design of powdered detergents. This is one reason why STPP is difficult to completely replace with a single raw material.

4. STPP Replacement Directions Based on Functional Deconstruction

STPP is a multifunctional builder, so the success of its replacement cannot be judged by a single indicator. At a minimum, replacement should be evaluated by breaking down five types of functions.

Function Provided by STPP	Underlying Action	Capability That Must Be Restored in Replacement
Hard-water softening	Controls Ca²⁺ and Mg²⁺	Reduces free calcium and magnesium ions and minimizes hard-water interference
Metal-ion complexation	Forms complexes with metal ions	Controls the effects of trace metals such as iron, copper, and manganese
Alkalinity and buffering	Helps maintain washing pH	Maintains pH conditions suitable for soil removal
Dispersion and anti-redeposition	Reduces soil reattachment	Controls ash, scale, and particulate soil deposition
Powder-system compatibility	Improves powder structure and storage performance	Maintains flowability, anti-caking performance, and processing stability

5. Why Do Cleaning Formulations Need Phosphorus-Free or Low-Phosphorus Replacement Systems?

5.1 STPP Has Both Performance Advantages and Use Limitations

STPP offers mature builder performance, reasonable cost, and good compatibility with powder systems. From the perspective of traditional washing performance, it remains an effective classic builder. The reason it has been replaced in many consumer cleaning products is mainly due to phosphorus-containing discharge, regulatory requirements, demand for phosphorus-free products, and changes in product formats.

5.2 Phosphorus-Containing Discharge and the Risk of Eutrophication

STPP is a phosphorus-containing raw material. When phosphorus from detergent wastewater enters water bodies, it may increase the total phosphorus load. Excessive nutrients such as nitrogen and phosphorus in water bodies may promote abnormal algal growth, leading to eutrophication and affecting dissolved oxygen levels and ecological balance.

Therefore, many regions restrict phosphorus-containing detergents or encourage consumer cleaning products to move toward phosphorus-free and low-phosphorus formulations. EU regulations have set total phosphorus limits for phosphates and other phosphorus compounds in consumer laundry detergents and consumer automatic dishwasher detergents. These regulations are not equivalent to a complete “phosphorus ban”; rather, they control total phosphorus levels according to product category and recommended dosage. In China, some regions, key watersheds, or specific administrative areas have also imposed varying degrees of restrictions on the sale and use of phosphorus-containing detergent products in line with water-ecology protection requirements, while promoting greener and phosphorus-free detergent products.

5.3 Formulation Demands Driven by Changes in Product Formats

Traditional STPP systems are well suited to powdered detergents. As cleaning products move toward liquid formats, concentrated products, transparent systems, low-temperature washing, and easier rinsing, the compatibility of STPP becomes somewhat limited.

Product Change	Impact on Builder System
Liquid formats	Require more soluble, stable builders with low precipitation tendency
Concentrated formats	Limited formulation space requires more efficient additive combinations
Transparent products	Not suitable for insoluble particles or inorganic salts that easily precipitate
Low-temperature washing	Requires builders to act quickly even at low temperatures
Phosphorus-free trend	Requires reducing or avoiding the use of phosphorus-containing builders

6. Mechanisms and Application Directions of Common STPP Alternatives

6.1 Zeolite 4A: Mainly Replacing the Hard-Water Softening Function

Zeolite 4A is a sodium aluminosilicate commonly used in phosphorus-free laundry powders and tablet systems. Its core mechanism is ion exchange rather than water-soluble complexation. Its structure contains exchangeable Na⁺. When Ca²⁺ is present in the washing water, Ca²⁺ can exchange with Na⁺ in the zeolite, thereby reducing the concentration of calcium ions in the water.

Zeolite 4A mainly replaces the hard-water softening function of STPP, especially the control of Ca²⁺. Its advantages are that it is phosphorus-free, relatively cost-controllable, and suitable for powder systems.

However, zeolite 4A cannot fully replicate the functions of STPP:

① It is not a true water-soluble chelating agent;

② Its control of Mg²⁺ usually requires synergy with other additives;

③ Its actual performance is affected by particle size, dispersibility, exchange rate, washing time, and temperature;

④ It is not suitable for transparent liquid products;

⑤ It usually requires synergy with components such as polycarboxylates, carbonates, and silicates.

Therefore, zeolite 4A is more suitable as a calcium-ion-exchange-type main builder in powdered detergent systems. In transparent liquid systems, low-residue systems, or systems sensitive to insoluble particles, it is generally not suitable as the main builder.

6.2 EDTA-2Na: Mainly Replacing Strong Metal-Ion Complexation

EDTA-2Na is a typical aminocarboxylate chelating agent. The carboxyl groups and nitrogen atoms in its molecule can form stable complexes with metal ions. It has strong control capability for Ca²⁺, Mg²⁺, and metal ions such as Fe³⁺ and Cu²⁺.

EDTA-2Na can replace part of the metal-ion complexation function of STPP, especially in controlling the impact of trace metal ions on formulation stability. For example, iron and copper ions may affect product color, fragrance stability, oil oxidation, or the stability of bleaching systems. In such cases, EDTA-2Na can provide a clear benefit.

However, EDTA-2Na is not suitable as a complete replacement for STPP:

① It is mainly a chelating agent and does not provide a powder-structuring effect;

② It cannot make up for the alkalinity and powder-processing functions of STPP;

③ Large-dose use is limited by cost and formulation compatibility;

④ Its environmental persistence and biodegradation under conventional conditions are concerns, so it should be selected cautiously in formulations positioned as phosphorus-free, low-environmental-impact, or readily biodegradable.

6.3 Sodium Citrate: Mainly Replacing Mild Complexation and Buffering Functions

Sodium citrate is a carboxylate-type additive with a certain ability to complex calcium and magnesium, while also providing pH buffering. It has good water solubility, is mild in formulations, and is generally well accepted by consumers. It is commonly used in liquid laundry detergents, dishwashing liquids, personal cleansing products, and mild cleaning products.

Sodium citrate mainly replaces the following STPP functions:

① Light to moderate hard-water control;

② pH buffering;

③ Stabilization of liquid systems;

④ Partial builder and anti-deposition effects.

However, the chelating ability of sodium citrate is usually insufficient for it to independently perform all STPP functions under high-hardness or heavy-soil conditions. If a formulation is intended for heavy-duty cleaning or high-water-hardness regions, sodium citrate usually needs to be combined with other chelating agents, dispersants, or alkaline agents.

6.4 Sodium Gluconate: Mainly Replacing Alkaline Complexation, Scale Inhibition, and Dispersion Functions

Sodium gluconate is a hydroxycarboxylate additive that can form complexes with various metal ions. Under alkaline conditions, it provides good control of ions such as calcium, iron, and copper, and also offers certain auxiliary effects in scale inhibition, dispersion, and corrosion inhibition.

Sodium gluconate is mainly suitable for replacing the following STPP functions:

① Metal-ion control in alkaline systems;

② Scale inhibition in hard-surface cleaning;

③ Deposit control in industrial cleaning;

④ Complexation and stability support in liquid cleaning systems.

Its application scope differs from that of sodium citrate. Sodium citrate is more oriented toward mild liquid detergents and buffering systems, while sodium gluconate is more suitable for alkaline cleaning, hard-surface cleaning, equipment cleaning, and some industrial cleaning systems. Sodium gluconate also cannot fully replace STPP. It is not a typical main builder in powdered detergents and cannot independently provide the powder-structuring, comprehensive builder performance, and cost balance of STPP.

6.5 Polycarboxylates: Mainly Supplementing Dispersion, Scale Inhibition, and Anti-Redeposition

Polycarboxylates are not the primary water-softening replacement for STPP, but they are important co-builders. Their main functions are dispersing particulate soils, inhibiting inorganic salt scaling, and reducing soil and ash redeposition.

In zeolite 4A systems, polycarboxylates are particularly important. Because zeolite 4A itself is an insoluble particle, insufficient dispersion in the system may affect washing residues and fabric deposition. Polycarboxylates can compensate for the insufficient dispersion and anti-redeposition performance of phosphorus-free powder systems. Polycarboxylates are suitable as co-builders rather than as standalone main raw materials for replacing STPP.

6.6 Sodium Carbonate and Sodium Silicate: Mainly Supplementing Alkalinity and Powder Structure

Sodium carbonate and sodium silicate are commonly used in powdered detergents. Their replacement relationship with STPP is mainly reflected in alkalinity, precipitation-type water softening, corrosion inhibition, and powder structure.

Sodium carbonate can provide alkalinity and reduce the effect of some hard-water ions by forming precipitates such as calcium carbonate. Sodium silicate can provide alkalinity, improve powder structure, and offer corrosion inhibition for certain metal materials. However, precipitation-type softening by carbonates may lead to inorganic deposition, so they usually need to be used together with dispersants, zeolites, or chelating agents.

6.7 MGDA and GLDA: High-Performance Soluble Chelating Directions

Methylglycinediacetic acid (MGDA) and tetrasodium glutamate diacetate (GLDA) are commonly used soluble chelating-agent directions in modern phosphorus-free cleaning formulations. They can complex calcium, magnesium, and various transition metal ions, and are suitable for liquid detergents, dishwasher detergents, hard-surface cleaners, and industrial cleaning agents.

Compared with traditional chelating agents such as EDTA-2Na, MGDA and GLDA are generally more suitable for cleaning formulations positioned as phosphorus-free, biodegradable, or environmentally friendly. However, their cost is relatively high, and their use still needs to be comprehensively evaluated based on product positioning, target water quality, pH conditions, dosage cost, and cleaning-performance requirements.

7. Selecting STPP Replacement Systems by Product Type

7.1 Laundry Powders and Powdered Cleaners

Most powdered detergent systems can tolerate insoluble builders, so zeolite 4A can be used as the main builder in phosphorus-free systems. However, zeolite 4A alone is usually insufficient to fully replace STPP. Hard-water softening, alkalinity adjustment, soil dispersion, and powder-structuring functions must be restored through compound formulation. Common approaches include:

Functional Requirement	Recommended Direction
Main water softening	Zeolite 4A
Alkalinity supplementation	Sodium carbonate, sodium silicate
Dispersion and anti-redeposition	Polycarboxylates
Trace-metal control	Small amounts of EDTA-2Na, MGDA, GLDA, or sodium gluconate
Powder structure	Silicates, carbonates, and other powder additives

The key to replacing STPP in powder systems is to rebuild hard-water softening, alkalinity, dispersion, and powder performance through a combined formulation approach.

7.2 Liquid Laundry Detergents and Transparent Liquid Cleaners

Liquid systems must prioritize solubility, transparency, low-temperature stability, and long-term storage stability. Zeolite 4A is insoluble in water and is generally not suitable as the main builder in transparent liquid products. Liquid systems are more suited to the following options:

Functional Requirement	Recommended Direction
Mild complexation and buffering	Sodium citrate
Alkaline complexation and scale inhibition	Sodium gluconate
High-performance hard-water control	MGDA, GLDA
Trace-metal stabilization	Small amounts of EDTA-2Na, MGDA, GLDA
Anti-deposition	Polycarboxylates or other dispersants

7.3 Hand Dishwashing Detergents and Mild Cleaners

Hand dishwashing detergents usually need to balance oil removal, easy rinsing, low residue, and mildness for skin contact. Such products generally should not use overly strong inorganic alkaline systems, nor are they suitable for directly adopting the high-inorganic-salt builder framework used in powdered detergents.

For such formulations, sodium citrate, sodium gluconate, or appropriate amounts of soluble chelating agents may be prioritized. Sodium citrate can provide mild buffering and basic hard-water control. Sodium gluconate helps improve metal-ion control and reduce scale residues. In high-hardness regions or enhanced-cleaning products, soluble chelating agents such as methylglycine diacetates and glutamate diacetates may be introduced appropriately.

7.4 Dishwasher Detergents

Dishwasher detergents place more complex demands on builder systems. They must not only remove oils, starches, and protein soils, but also control water spots, glass haze, inorganic scaling, and the stability of bleaching systems.

Therefore, phosphorus-free dishwasher systems usually require:

① Soluble strong chelating agents to control calcium and magnesium;

② Carbonates and silicates to provide alkalinity;

③ Polycarboxylates to control scaling and deposition;

④ Bleaching agents and enzyme systems to work synergistically for soil removal;

⑤ Corrosion-inhibition systems adapted to glass, metal, and plastic materials.

The performance of this product category should not be judged by a single replacement ingredient. Comprehensive formulation validation is required.

7.5 Hard-Surface Cleaning and Industrial Cleaning

Hard-surface cleaning and industrial cleaning often involve high pH, high water hardness, heavy inorganic deposits, or metal-ion interference. In such systems, sodium gluconate, polycarboxylates, silicates, carbonates, and strong chelating agents are more commonly used.

Sodium gluconate provides good metal-ion control and scale-inhibition effects in alkaline systems. It is suitable for equipment cleaning, floor cleaning, hard-surface pre-descaling treatment, and some industrial cleaning systems. If stronger hard-water control is needed, it can be compounded with MGDA, GLDA, EDTA-2Na, or polycarboxylates.

8. How to Evaluate and Validate STPP Replacement Systems

8.1 Selection by Product Format

Product format determines the first choice of builder system. Powdered products, liquid products, hand dishwashing detergents, dishwasher detergents, and industrial cleaning systems have different requirements for builder solubility, alkalinity, chelating ability, dispersion ability, and storage stability. Therefore, the same replacement system cannot be used across all product types.

Product Format	Suitable Replacement Direction	Reason for Selection
Laundry powders and powdered cleaners	Zeolite 4A, sodium carbonate, sodium silicate, polycarboxylates	Most powder systems can tolerate insoluble builders and are suitable for building phosphorus-free powder builder systems
Liquid laundry detergents and transparent liquid cleaners	Sodium citrate, sodium gluconate, methylglycine diacetates, glutamate diacetates, small amounts of disodium EDTA	Require soluble, stable builder systems that do not readily precipitate
Hand dishwashing detergents and mild cleaners	Sodium citrate, sodium gluconate, appropriate amounts of soluble chelating agents	Need to balance mildness, oil removal, hard-water control, and easy rinsing
Dishwasher detergents	Soluble strong chelating agents, alkaline agents, polycarboxylates, bleaching agents, and enzyme systems	Need to simultaneously control water spots, scaling, bleaching stability, and multiple soil types such as oils, starches, and proteins
Hard-surface cleaners and industrial cleaners	Sodium gluconate, polycarboxylates, silicates, methylglycine diacetates, glutamate diacetates, disodium EDTA	Mainly focus on stability under alkaline conditions, scale inhibition, metal-ion control, and deposit control

8.2 Selection by Main Formulation Problem

Different formulations need to solve different problems, so replacement approaches also differ.

Main Formulation Problem	Direction to Prioritize
Reduced detergency caused by high water hardness	Zeolite 4A, MGDA, GLDA, sodium citrate, sodium gluconate
Discoloration, oxidation, or bleaching failure caused by trace metals	EDTA-2Na, MGDA, GLDA, sodium gluconate
Soil redeposition and fabric graying	Polycarboxylates, dispersants, zeolite-based compound systems
Insufficient oil removal	Joint adjustment of alkalinity system, surfactant system, and builder system
Scale, water spots, and inorganic residues	Chelating agents, scale inhibitors, polycarboxylates
Demand for phosphorus-free, low-phosphorus, or readily biodegradable formulations	Phosphorus-free systems such as sodium citrate, sodium gluconate, MGDA, and GLDA

8.3 Selection by pH Conditions

The effectiveness of builders is closely related to pH. The same additive may show different complexation ability, stability, and formulation performance at different pH values.

pH Condition	More Suitable Builder Direction
Weakly acidic to neutral	Sodium citrate, some soluble chelating agents
Neutral to mildly alkaline	Sodium citrate, sodium gluconate, MGDA, GLDA
Alkaline	Sodium gluconate, MGDA, GLDA, sodium carbonate, sodium silicate, polycarboxylates
Strongly alkaline industrial systems	Sodium gluconate, polycarboxylates, silicates, strong chelating agents

8.4 Selection by Environmental Requirements and Cost

STPP replacement is not only a technical issue; it also involves product positioning and cost control. If a product focuses on standard cleaning performance and high cost-effectiveness, powder systems may prioritize a combination of zeolite 4A, sodium carbonate, sodium silicate, and polycarboxylates.

If a product is positioned as phosphorus-free, low-residue, mild-cleaning, or biodegradable, liquid systems are more suitable for soluble phosphorus-free builders such as sodium citrate, sodium gluconate, MGDA, and GLDA. If the product is intended for high-hardness water, heavy-duty cleaning, or automatic dishwashing applications, it is not enough to focus only on phosphorus-free, low-phosphorus, or biodegradable attributes. The system must also ensure that chelation, scale inhibition, alkalinity, and anti-deposition performance meet actual cleaning requirements.

8.5 Performance Validation After Replacement

STPP replacement must be verified through application testing. This is especially important for phosphorus-free systems, whose performance usually comes from the synergy of multiple additives. A single raw-material indicator cannot represent final cleaning performance.

Validation Item	Purpose of Evaluation
Detergency under different water-hardness conditions	Determines whether hard-water control is sufficient
Whiteness retention and ash deposition	Evaluates anti-redeposition capability
Foam behavior and rinsing performance	Determines whether surfactants are affected by hard-water ions
pH and alkali reserve	Evaluates whether oil removal and buffering remain stable
Low-temperature and high-temperature storage	Evaluates liquid stability or powder-caking risk
Scale, water spots, and inorganic residues	Evaluates scale inhibition and easy-rinsing performance
Metal-ion stability	Determines whether color, fragrance, bleaching systems, or enzyme systems are affected
Cost and effective dosage	Determines whether the solution has practical application value

9. Product Tables for Sodium Tripolyphosphate Replacement, Low-Phosphorus/Phosphorus-Free Builder Systems, and Comparative Studies

Table 1. Phosphate Prototype Builders, Zeolite-Based Water Softeners, and Inorganic Alkaline Builders

Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Phosphate prototype builder	7758-29-4	S433949	Sodium Tripolyphosphate	Industrial grade, ≥85%	A classic phosphorus-containing builder, used as a reference sample for hard-water complexation, surfactant performance enhancement, soil dispersion, and sodium tripolyphosphate replacement studies
Phosphate builder	7722-88-5	S108847	Sodium Pyrophosphate	AR, ≥99%	A phosphate-based complexing and buffering additive, suitable for comparison of phosphorus-containing builder systems, calcium and magnesium ion control experiments, and detergent-builder screening
Phosphate dispersing builder	10124-56-8	S108858	Sodium Hexametaphosphate (SHMP)	AR	A phosphate-based dispersing and complexing additive, suitable for water softening, inorganic salt dispersion, and comparative experiments in phosphorus-containing builder systems
Zeolite-based phosphorus-free water softener	1318-02-1	P103646	Synthetic Zeolite	Particle size ≤10.0 μm	A sodium aluminosilicate phosphorus-free builder, used for calcium ion exchange, powdered detergent builder systems, and phosphorus-free sodium tripolyphosphate replacement studies
Aluminosilicate phosphorus-free builder	1344-00-9	S190621	Sodium Aluminosilicate	≥82% SiO₂ basis (based on calcined substance)	An aluminosilicate builder raw material used in powdered cleaners for water softening, adsorption, dispersion systems, and zeolite-based replacement-system studies
Inorganic alkaline builder	497-19-8	S111737	Sodium Carbonate, Anhydrous	ACS, ≥99.5%	An inorganic alkaline source and precipitation-type water-softening additive, used in laundry powders, hard-surface cleaners, alkalinity adjustment, and phosphorus-free builder compound systems
Mild alkaline buffer	144-55-8	S112331	Sodium Bicarbonate	AR, ≥99.8%	A mild alkaline source and buffering agent, used in mild cleaning systems, acid-base buffering experiments, and low-irritation builder formulation studies
Silicate inorganic builder	1344-09-8	S302436	Powdered Instant Sodium Silicate	For use as a synthetic detergent builder	A silicate alkaline builder used for alkalinity supplementation, corrosion inhibition, particle-structure control, and phosphorus-free builder-system compounding in powdered detergents
Silicate alkaline builder	6834-92-0	S102095	Sodium Metasilicate, Anhydrous	SiO₂, 44–47%	A highly alkaline silicate additive used in heavy-duty cleaning, industrial cleaning, oil removal, and alkaline builder-system studies
Silicate alkaline builder	10213-79-3	S100563	Sodium Metasilicate Pentahydrate	≥95%	A silicate alkaline builder used in powdered cleaners, hard-surface cleaning, corrosion-inhibition evaluation, and alkaline compound-system experiments

Table 2. Organic Acid Salts, Buffers, and Mild Complexing Additives

Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Carboxylate mild complexing agent	527-07-1	G278703	D-Sodium Gluconate	≥99%	A hydroxycarboxylate complexing additive used for metal ion control in alkaline systems, scale inhibition, hard-surface cleaning, and partial functional replacement studies of sodium tripolyphosphate
Organic acid complexing agent	526-95-4	G111173	D-Gluconic Acid Solution	49–53 wt. % in H₂O	An acidic raw material for gluconate systems, used for complexing-system construction, pH adjustment, metal ion control, and scale-inhibition experiments
Carboxylate buffering complexing agent	6132-04-3	S116311	Sodium Citrate Dihydrate	AR, ≥99%	A mild complexing and buffering additive used in liquid laundry detergents, dishwashing detergents, calcium and magnesium ion control, and phosphorus-free liquid builder systems
Carboxylate buffering complexing agent	68-04-2	S189183	Sodium Citrate	≥98%	A soluble phosphorus-free builder component used for mild hard-water control, pH buffering, liquid cleaner stability, and builder compound experiments
Organic acid pH adjuster	77-92-9	C639638	Citric Acid	Moligand™, ≥99.5%	An organic acid pH adjuster used in citrate buffer systems, complexing-system construction, and acid-base balance studies for liquid cleaners
Organic acid pH adjuster	5949-29-1	C433031	Citric Acid Monohydrate	Reagent grade, ≥98% (GC/T)	A common hydrated form of citric acid, used in buffer systems, chelating systems, pH adjustment, and phosphorus-free cleaning formulation studies

Table 3. Metal Ion Chelating Agents and Scale Inhibitors

Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Soluble green chelating agent	51981-21-6	T303874	Tetrasodium N,N-Bis(carboxymethyl)-L-glutamate	Active content ≥47%	A soluble aminocarboxylate chelating agent used for calcium and magnesium ion control, liquid cleaners, dishwasher detergents, and phosphorus-free builder-system studies
Traditional strong chelating agent	6381-92-6	E116429	Disodium EDTA Dihydrate	GR, ≥99%	A strong metal ion control agent used for calcium, magnesium, iron, and copper ion complexation, formulation stability evaluation, and comparative experiments on the chelating function of sodium tripolyphosphate
Traditional strong chelating agent	139-33-3	D684233	Disodium EDTA	≥99%	A strong chelating agent used for trace metal ion control, liquid cleaner stabilization, hard-water interference evaluation, and complexing-capacity testing
Traditional strong chelating agent	10378-23-1	E109307	Tetrasodium EDTA Dihydrate	AR, ≥99% (T)	A strong chelating agent for alkaline systems, used in high-pH cleaning systems, metal ion sequestration, hard-water softening, and formulation stability experiments
Traditional strong chelating agent	140-01-2	D302814	Pentasodium Diethylenetriaminepentaacetate	ca. 50% in water	A polycarboxylate-type strong chelating agent used for iron and copper ion control, bleaching-system stabilization, industrial cleaning, and high-chelation-demand experiments
Traditional chelating agent	5064-31-3	T189148	Trisodium Nitrilotriacetate (NTA)	≥99%	An aminocarboxylate chelating agent used for metal ion complexation, hard-water control comparison, and studies of traditional chelating systems
Soluble green chelating agent	164462-16-2	T161558	Trisodium N-(1-Carboxyethyl)iminodiacetate	≥95% (T)	A soluble aminocarboxylate chelating agent used in phosphorus-free cleaners, automatic dishwashing systems, hard-water control, and sodium tripolyphosphate replacement formulation studies
Biodegradable chelating agent	144538-83-0	T302889	Tetrasodium Iminodisuccinate	AR	A succinate-type chelating agent used in phosphorus-free formulations, calcium and magnesium ion control, green cleaners, and chelating-agent replacement studies
Phosphorus-containing scale inhibitor	2809-21-4	E107456	1-Hydroxyethylidene-1,1-diphosphonic Acid (HEDP)	Moligand™, 60% aqueous solution	A phosphonate scale-inhibition and metal ion control agent used in industrial cleaning, hard-surface cleaning, scale control, and corrosion-inhibition system experiments
Phosphonate scale inhibitor	6419-19-8	N466698	Nitrilotris(methylenephosphonic Acid) Solution	50 wt. % in H₂O	A phosphonate scale and corrosion inhibitor used for metal ion control, scale suppression, industrial cleaning, and hard-water system evaluation

Table 4. Polymeric Dispersion, Scale-Inhibition, and Anti-Redeposition Additives

Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Anti-redeposition agent	9004-32-4	C104986	Sodium Carboxymethyl Cellulose (CMC)	Viscosity: 1000–1400 mPa·s, USP grade	A cellulose-based anti-redeposition agent used for fabric whiteness retention, particulate soil suspension, and builder-system studies in laundry powders and liquid laundry detergents
Polycarboxylic acid dispersing and scale-inhibition agent	9003-01-4	P661414	Poly(acrylic acid) (PAA)	Viscosity ≤2000 cP (25°C)	A polycarboxylic acid dispersant used for calcium salt scale inhibition, particulate soil dispersion, phosphorus-free builder systems, and hard-water deposit control experiments
Polyvinyl dispersing stabilizer	9003-39-8	P110608	Polyvinylpyrrolidone (PVP)	Average molecular weight 8000, K16–18	A water-soluble polymer used for dye-transfer inhibition, soil dispersion, liquid cleaner stabilization, and auxiliary evaluation of detergent systems
Polycarboxylate dispersing and scale-inhibition agent	9003-04-7	P434409	Sodium Polyacrylate (PAAS)	Average Mw ~8000, 45% in H₂O	A polycarboxylate dispersing and scale-inhibition agent used in phosphorus-free detergents, zeolite 4A synergy, anti-redeposition, and inorganic deposit control
Copolymer dispersing and scale-inhibition agent	26677-99-6	P303284	Acrylic Acid-Maleic Acid Copolymer	Solids content ≥48%	A carboxylate copolymer dispersing and scale-inhibition agent used for calcium and magnesium salt deposit control, particle dispersion, detergent-builder compounding, and hard-surface cleaning systems

Note: The above are representative Aladdin products related to research and formulation studies. They can be used for STPP replacement, screening of low-phosphorus/phosphorus-free builder systems, and comparative studies. For specific product specifications, grades, COA, SDS, and regulatory applicability, please refer to the Aladdin website and the corresponding batch documents.

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