Grade selection, specification writing, safety data and the practical problems of moving chemistry across borders. Written for procurement managers, formulators and plant chemists — not for search engines.
A technical guide to what solvents are, how dissolution works, the main solvent classes and the properties that decide which one you specify.
What potassium sorbate (E202) is: the C6H7KO2 formula, 74.6% sorbic acid, how it preserves food, how much to add per gallon of wine or mead, sorbate vs sodium benzoate and grades.
Silver nitrate explained: formula and properties, how it is made, uses in analysis, mirrors and photography, grades, safe handling and the HS code.
Guar gum powder explained: the galactomannan from guar seed, how it is milled, its grades and uses, US use limits, JECFA specifications and the HS code.
Zinc nitrate explained: the Zn(NO3)2 formula and hexahydrate, molar mass and zinc content, solubility, heating reaction, uses, hazards and UN 1514 transport.
Calcium hypochlorite explained: the Ca(OCl)2 formula, what available chlorine means, grades and bleaching powder, uses, safe storage and UN 1748 transport.
Sodium silicate (water glass) explained: the Na2SiO3 formula and SiO2:Na2O ratio, Baumé and grades, how it is made, its uses, hazards and transport.
Lead nitrate explained: the Pb(NO3)2 formula and molar mass, colour and solubility, what heating it produces, grades, industrial uses, toxicity and UN 1469 transport.
Potassium metabisulfite explained: the formula K2S2O5, E224, its 57.6% SO2 content, how much to add per gallon or litre of wine, Campden tablets, potassium vs sodium metabisulfite and safe storage.
Glacial acetic acid explained: the CH3COOH formula, why it freezes at 16.6 °C, purity grades, properties, VAM, PTA and food uses, UN 2789 and safe storage.
Sodium thiosulfate explained: the formula Na2S2O3, molar mass 158.11, pentahydrate vs anhydrous, how it neutralises chlorine in water and pools, iodometric titration, grades and safe storage.
Ammonium carbonate explained: the formula (NH4)2CO3, molar mass 96.09, why commercial grades are a bicarbonate and carbamate mixture, E503, baking uses and storage.
Barium sulphate explained: the formula BaSO4, molar mass 233.39, why it is white and insoluble, blanc fixe vs natural barytes, HS codes, and its drilling, paint and plastics uses.
Acetyl chloride (CH3COCl, CAS 75-36-5) and thionyl chloride (SOCl2, CAS 7719-09-7) compared: boiling points, water reactivity, hazards, UN and HS numbers and export controls.
Copper II sulfate pentahydrate explained: the formula CuSO4·5H2O, molar mass 249.69, 25.4 percent copper, why it turns white on heating, grades, fungicide, feed and plating uses.
Cetostearyl alcohol explained: the cetyl/stearyl blend, INCI cetearyl alcohol, grades, melting range, how it stabilises creams and lotions, and how to source it for export.
Sodium metabisulphite explained: the formula Na2S2O5, molecular weight 190.11, 67.4 percent SO2, E223 food use, water treatment, grades and sodium vs potassium.
Menthol explained: formula C10H20O, molecular weight 156.27, why only l-menthol cools, natural vs synthetic, crystal grades and how to buy against a specification.
Aluminium sulphate explained: the formula Al2(SO4)3, molecular weight 342.15, why commercial alum is quoted as percent Al2O3, ferric vs non-ferric, and water treatment use.
Hydrochloric acid explained: what HCl stands for, hydrogen chloride versus hydrochloric acid, 30 to 33 percent and Baume strengths, materials of construction and uses.
Nitric acid explained: the formula HNO3, CAS 7697-37-2, why 68 percent is the azeotrope, weak versus fuming acid, passivation, and the controls on supply.
Ammonium hydroxide explained: the NH4OH formula, why aqueous ammonia strengths run inverse to density, 25 percent solution, materials to avoid and industrial uses.
Citric acid explained: the formula C6H8O7, molecular weight, why anhydrous and monohydrate are priced differently, the three pKa values, E330 food grade and bulk supply.
Zinc sulphate explained: ZnSO4 formulas and molecular weights, why heptahydrate is 22 percent zinc and monohydrate 36 percent, agriculture, feed and plating grades.
Magnesium chloride explained: MgCl2 formula and molecular weight, the hexahydrate and bischofite, why it is deliquescent, de-icing, tofu nigari and industrial uses.
Isobutyl alcohol explained: the structure of isobutanol, C4H10O and CAS 78-83-1, boiling point 108 degrees C, how the four butanol isomers differ, and industrial uses.
Sodium chloride explained: NaCl formula and molecular weight, melting point, solubility, how solar, rock and vacuum salt differ, and the grades industry actually buys.
Acetone explained: the formula C3H6O, CAS 67-64-1, boiling point 56 degrees C, density 0.79, how technical, AR, HPLC and pharma grades differ, and how it is shipped.
Sodium sulphate explained: Na2SO4 formula and molecular weight, anhydrous versus Glauber's salt, the 32.4 degree solubility peak, detergent and glass grades, and uses.
Benzaldehyde explained: C6H5CHO structure and molecular weight 106.12, boiling point, why it oxidises to benzoic acid in air, natural versus synthetic grades and uses.
Sodium carbonate explained: the formula Na2CO3, why soda ash and washing soda are the same chemical in different forms, light vs dense grades, uses and bulk supply.
Where to buy phosphoric acid: wet vs thermal process, technical, food, pharma and electronic grades, 85% and P2O5 strength, UN 1805, packing and bulk supply.
What hypromellose (hydroxypropyl methylcellulose, HPMC) is, how substitution types like 2910 and 2208 read, what viscosity grades mean, and how to specify it.
How to dispose of muriatic acid (hydrochloric acid): what never to do, neutralising small amounts, household hazardous waste routes and commercial rules.
Is mineral oil flammable? No - it is combustible. Flash points, GHS and NFPA 30 classification, autoignition, oily rag risk, storage and shipping.
A technical guide to caustic soda (sodium hydroxide): what it is, why it is a strong base, the grades actually traded, its industrial uses and how to buy it.
What bleach is chemically, why it is alkaline rather than acidic, why it is not flammable but is still hazardous, and how industrial grades are specified.
A procurement and specification guide to buying sulphuric acid: grades, purity limits, applications, materials of construction, UN classification and export documentation.
Propylene glycol is bought through different channels depending on grade and volume — this guide covers grades, specifications and how to buy in bulk.
Most of these pieces began as a question from a buyer: which grade do I actually need, why did my assay drop in transit, what has to be on the certificate for customs to release this. Rather than answer it once, we write it down.
Nothing here is a specification for a Scapex product. Where a figure would be commercially specific, we give the typical commercial range and tell you to work from the certificate of analysis for the material you have actually been offered.
Send it with your specification. If it is a good question, it usually becomes the next article.
