Linear Alkyl Benzene Sulphonic Acid LABSA 96%

For household heavy-duty laundry liquids, pumpable detergent pastes and manual dishwashing liquids, 96% linear alkyl benzene sulphonic acid serves as the primary anionic precursor and is continuously converted to its sodium salt by neutralisation with 50% aqueous sodium hydroxide. The addition ratio is formulation-dependent: economy laundry liquids use 2.0–6.0 wt% of LABSA 96% on final mass, standard heavy-duty laundry liquids use 6.0–10.0 wt%, concentrated manual dishwashing liquids use 10.0–14.0 wt%, and pumpable detergent pastes may reach 18.0–22.0 wt% in the aqueous phase before final dilution. Neutralisation is carried out in an in-line rotor-stator mixer with a plate heat exchanger maintaining a set point of 35–45 °C, because the acid-base reaction is strongly exothermic. Batch temperatures above 45 °C produce a visible colour shift from amber to dark brown, while temperatures below 30 °C produce incomplete conversion and residual acid pockets. The pH of the neutralised base is held at 7.0–8.5 measured at 25 °C under ISO 4316; below 5.0 the formulation enters a high-yield-stress gel phase that blocks transfer pumps, and above 9.0 the product develops a viscosity break and may destabilise enzyme components. Free alkalinity is controlled at 0.2–0.5% Na₂O by ISO 4314, because excess free alkalinity above 0.5% is incompatible with protease and amylase enzyme systems added later. Anionic active matter after neutralisation is verified by two-phase titration according to ISO 2271; the target active-matter range for a typical laundry base is 20–30 wt% linear alkylbenzene sulfonate. Higher concentrations above 30 wt% require viscosity control with sodium xylene sulfonate hydrotrope at 1.0–3.0 wt% to prevent pipe cavitation in ring-lobe pumps. Hard water tolerance of the neutralised sulfonate is improved by dosing tetrasodium EDTA or sodium citrate at 0.2–0.5 wt%, particularly in regions where feed water exceeds 200 mg/L CaCO₃ equivalent. The finished home-care product placed on the European market must comply with Regulation (EC) No 648/2004, including the surfactant biodegradability criterion measured under OECD 301B at ≥60% ThCO₂ evolution within 28 days, and labelling of preservatives and allergens as required by Annex VII. The resulting terminal product types include low-viscosity machine laundry liquids, high-viscosity manual dishwashing liquids, single-dose water-soluble sachet detergents, and industrial laundry pre-spotters, with the target viscosity profile and desired dilution factor controlling the formula composition.

When LABSA 96% Is Charged as the Acidic Phase in Industrial Degreasers

When 96% LABSA is charged directly into acidic industrial degreasers, the acid form functions simultaneously as an anionic wetting agent and as an acidic pH control agent, replacing part of the phosphoric or citric acid demand in transport cleaning and metal pretreatment. The addition ratio in vehicle wheel cleaners and engine degreasers is 4.0–12.0 wt% LABSA 96% on final batch mass, while truck wash pre-soak concentrates may use 8.0–18.0 wt% when subsequently diluted 1:20 to 1:40 at the trigger gun. Batch preparation is carried out in 316L stainless steel or polypropylene agitated vessels because the final pH is commonly below 2.0; pump seals and gaskets must be PTFE or EPDM, and carbon steel pipework is excluded due to acid corrosion. The raw material is classified under Regulation (EC) No 1272/2008 as Skin Corrosion Category 1B and requires a REACH-compliant safety data sheet with exposure scenarios under Annex II of Regulation (EC) No 1907/2006. Industrial detergent formulations placed on the European market also fall under Regulation (EC) No 648/2004, where the anionic surfactant must demonstrate ready biodegradability under OECD 301B at ≥60% within 28 days. The manufacturing sequence is critical: LABSA 96% is prediluted with 10–15 parts demineralised water under vortex mixing before any acid electrolyte is added, and open-flame heating is avoided because localised hot spots can produce acidic mist and darken the sulfonic acid phase. Corrosion inhibition is mandatory for metal-contact formulations; benzotriazole or sodium molybdate is dosed at 0.1–0.5 wt% and its performance is verified by gravimetric corrosion coupon testing under ASTM G31-72. The formulation is incompatible with sodium hypochlorite and calcium chloride, because the former releases chlorine gas at low pH and the latter forms insoluble calcium dodecylbenzene sulfonate that settles as a sticky filter-blocking precipitate. Terminal product types include phosphoric acid-based truck wash pre-soak, solvent-emulsified engine degreaser, acidic toilet bowl cleaner, and aluminium wheel cleaner where the corrosion inhibitor package is adjusted for non-etching use on anodised surfaces.

Continuous open-width scouring of cotton and cotton/polyester blends uses 96% LABSA after predilution to a 10–15% active solution, dosed into the wetting bath at 0.5–2.0 g/L on bath weight for grey fabric preparation. In pad-steam scouring, the fabric is impregnated on a horizontal padding mangle at 80–85% pickup, steamed at 98–100 °C for 45–60 min, and washed in a three- or four-compartment open-width washer with a counterflow temperature gradient from 85 °C to 40 °C; the anionic sulfonate lowers fabric-water interfacial tension and suspends waxes, pectins and seed-husk fragments removed from the cotton cuticle. For reactive dye soaping after exhaust dyeing, the addition is increased to 1.0–3.0 g/L at 90 °C for 15–20 min, where the surfactant forms micelles that solubilise hydrolysed reactive dye and prevent redeposition onto dyed yarn. The process is carried out under the chemical input constraints of ZDHC Manufacturing Restricted Substances List Version 3.1, and residual anionic surfactant on finished goods is evaluated against OEKO-TEX Standard 100 Annex 4 limits if the fabric is marketed as an infant article. The surfactant is anionic and must not be combined with cationic quaternary softeners or cationic dye-fixing agents in the same bath, because the resulting ionic complex precipitates onto fibre surfaces as a tacky, lightfastness-reducing deposit. High hardness in process water above 200 mg/L CaCO₃ reduces detergency and foam stability; the bath is conditioned with tetrasodium EDTA or sodium gluconate at 0.2–0.5 g/L. Terminal product types include bleached cotton knit, woven shirting, terry towelling, and denim prepared for subsequent dyeing or finishing, with residual surfactant removal confirmed by methylene blue active substance measurement in the final wash water according to ISO 7875-1.

What Addition Range Prevents Over-Wetting in Bovine Hide Degreasing?

In drum degreasing of bovine hides, the addition of 96% LABSA at 0.5–1.5 wt% on raw hide weight during soaking and at 1.0–2.5 wt% during sheepskin degreasing provides anionic emulsification of natural fats without over-swelling the corium. The processing vessel is a stainless steel or polypropylene drum running at 6–12 rpm, with a float ratio of 100–150% water, a bath temperature of 25–30 °C, and a running time of 30–60 min; the bath pH is adjusted to 3.5–4.5 with dilute formic acid or with the sulfonic acid itself, which shifts the acid dissociation equilibrium toward the unionised acid form and improves fat wetting at the hide surface. LABSA is incorporated with a nonionic ethoxylated alcohol at a typical ratio of 1.0:0.3 to 1.0:0.5, because the mixed anionic-nonionic micelle has a stronger emulsification capacity for natural triglycerides than either surfactant alone. The operation is governed by ZDHC MRSL Version 3.1 and the Leather Working Group wastewater audit protocol, and the sulfonic acid must be classified and disclosed in the facility chemical inventory under Regulation (EC) No 1907/2006. Addition above 2.5 wt% on raw hide weight produces over-emulsification of structural fats, which leads to loose grain, excessive scud loss, and a reduction in tear strength measured according to ISO 3377-1 after drumming; below 0.5 wt% the degreasing effect is not detectable in gravimetric fat extraction. The spent float carries a high chemical oxygen demand from emulsified fats and requires on-site primary treatment with acid cracking at pH 2.5–3.0 before discharge. Terminal product types include chrome-tanned wet blue for automotive upholstery, vegetable-tanned upper leather for footwear, and gloving leather, with a target residual fat content below 2.0 wt% before tanning.

Agrochemical Emulsion Compatibility and pH Control

Formulation of oil-in-water emulsion concentrates with 96% LABSA requires amine neutralisation prior to high-shear mixing; the neutralised acid is incorporated into emulsifier packages at 2.0–6.0 wt% of the final concentrate alongside ethoxylated castor oil or tristyrylphenol ethoxylates. Neutralisation is performed with triethanolamine or isopropylamine to a pH of 5.0–6.5 in the aqueous phase, because the salt form is water-soluble while the acid form remains oil-soluble; this equilibrium influences spontaneous emulsification when the concentrate is diluted in hard water in the spray tank. The oil phase is heated to 40–50 °C and combined with the aqueous phase in a rotor-stator homogeniser at 1,500–3,000 rpm for 15–30 min, producing an emulsion with a droplet size D90 commonly below 5 µm when measured by laser diffraction. Emulsion stability is evaluated using the FAO/WHO Manual on development and use of specifications for pesticides (2016) and CIPAC method MT 36; the ready biodegradability of the surfactant component is determined by OECD 301B, and the final formulation is managed under Regulation (EC) No 1907/2006 Annex II for safety data sheet preparation. LABSA-derived sulfonates are anionic and are therefore incompatible with cationic active ingredients and cationic wetting agents, which form insoluble ion pairs and phase separation in the concentrate; compatibility trials are required before combining with bipyridylium herbicide formulations. Terminal product types include emulsifiable concentrates, oil-in-water emulsions, microemulsions, and crop oil concentrate adjuvants where the anionic sulfonate contributes cold-water spontaneous emulsification.

Preformed foam for non-autoclaved cellular concrete is generated from a stock solution in which 96% LABSA is neutralised to pH 7.0–8.0 with sodium hydroxide and compounded at 4.0–8.0 wt% with an amphoteric foam booster such as cocamidopropyl betaine; the working solution is then diluted at 1:30 to 1:40 with water before entering the foam generator. The generator operates with compressed air at 2.0–5.0 bar, producing preformed foam with a density of 40–80 g/L and a half-life above 45 min when measured by a graduated cylinder drainage test. The foam is folded into a cement slurry with a water-to-cement ratio of 0.45–0.60 in a paddle mixer for 2–4 min, targeting a wet cast density of 400–1,600 kg/m³; the anionic sulfonate stabilises air voids by lowering surface tension and preventing bubble coalescence during initial set. The foaming agent is tested according to ASTM C796-97, and the cured lightweight product is assessed for compressive strength using ASTM C495 with typical strength values of 0.5–4.0 MPa depending on density; these strength figures are laboratory ranges and not a guarantee for any specific mix design. Dosing above 8.0 wt% LABSA in the stock solution produces excess surface-active monomer in the pore water, which retards cement hydration and destabilises the foam by reducing the disjoining pressure in lamellae; dosing below 4.0 wt% gives a coarse bubble size distribution and higher wet density. Terminal product types include non-structural void-fill concrete, cellular lightweight concrete blocks, lightweight precast panels, and thermal insulation screeds, with the formulation adjusted for each cement grade and aggregate source.