Primary alcohol sulphates

Theoretically, the mechanism for ethoxylated alcohol sulphation is similar to primary alcohol sulphation, involving the rapid formation of a metastable product. The stoichiometry of this almost instantaneous and highly exothermic initial reaction corresponds again to more than one molecule of SO3 per molecule of feedstock ... 

The desired ethoxylate acid sulphate product formed is less prone to thermal decomposition than the primary alcohol sulphation acid product. This is usually attributed to the moderating influence of the ethoxylate chain on the reactivity of SO3, together with stability of the ethoxylate acid sulphate product. The alcohol ethoxylate acid sulphate requires rapid and efficient neutralisation to maintain good product quality (preventing by-products, notably dioxane) and colour. 

Efimov V.T. et al. (1980). Russian J. of Applied Chem. 52 p 1847 (Topic Primary Alcohol Sulphation Chemistry). 

Lohr J.W. (1958) JAOCS, p 532. (Topic Neutralisation of reaction product of primary alcohol sulphation). 

Paste concentrations are 30% AD/75% AD for Coco-type and 30% AD/60% AD for tallow-type primary alcohol sulphates. 

Primary alcohol sulphate safety information See 6.6.2.,alcohol ether sulphate safety information. 

The primary alcohol sulphate pastes with an active detergent vaiying between 30% and 75% AD are viscous liquids (see 5.6.1. and 6.6.3.)The apparent viscosity is dependant on AD concentration, temperature and the concentration of sodium salts (NaOH, Na2S04). High AD pastes tend not to deaerate and may therefore cause problems in bulk transfer. Pastes are stored in mildly agitated stainless steel vessels. Solidification should be avoided and therefore heating coils with hot water are required. The hot water temperature should be 45 C for Coco-PAS and 60"C for Alfol (C16 - CIS) PAS. 

Pastes are stored in mildly agitated stainless steel (304 L, 316 L) tanks. Polyester resins form suitable tank coatings when only mild steel tanks are available. Copper and its alloys may cause discolouration of the product and should be avoided. Temperatures below 15 should be avoided and therefore heating coils with warm water (40°C) are required. Ehiring storage, solutions of alcohol ether sulphate often tend to become acidic due to hydrolysis. Ways to prevent this have been described in section 6.5.3. and 6.6.4., storage and handling of primary alcohol sulphates. 

AlkyIbenzene sulphonation Primary alcohol sulphation Ethoxylated alcohol sulphation Alpha-olefin sulphonation (AOS)... 

Tungsten-catalysed oxidation of alcohols by hydrogen peroxide is achieved in high yield in the presence of tetra-n-butylammonium hydrogen sulphate [20-22]. Secondary alcohols are converted into ketones (>90%) [e.g. 21], but primary alcohols generally are oxidized completely to the carboxylic acids [21], Aldehydes are also oxidized to the carboxylic acids [e.g. 21]. In contrast, using procedure 10.7.8.B, which is adaptable to scale up, benzyl alcohols are converted into the aldehydes benzoic acids are only formed with an excess of hydrogen peroxide [22],... 

Ethoxylation is carried out in the same manner as for primary alcohols described earlier but, in general, only up to the 3-mol ethoxylate as a feedstock for some specialised ether sulphates. These products show some advantages in wetting and foaming applications compared to the straight alcohol sulphates. These twin tail surfactants require less co-surfactant to make microemulsions and emulsify 3-5 times more oil than sulphates made from linear hydrophobes. 

The preferred hydrophobes for the alkyl sulphate production are the Cg-ao primary alcohols although reaction of a-olefins yielding secondary alkylsulphates is possible too. Most of the recent alkylsulphates are derived from synthetic alcohols or alcohols of renewable raw materials (for more details see Section 1.2.1). The sulphation of primary alcohols with air- or nitrogen-diluted SO3 bear a strong resemblance to the sulphonation of LAB. At first, two molecules of SO3 add rapidly to an alcohol forming metastable monoalkylpyrosulphate [62,64, 82] ... 

Synthetic C12+ primary alcohols, produced mainly by the hydroformyl-ation of ethylene oligomers (previous section), compete with fatty alcohols derived from natural oils. They may be sulphated (to give an anionic product) or reacted with ethylene oxide to produce alcohol ethoxylates, the major non-ionic detergent components (possibly approaching IMt per annum worldwide) ... 

The process consists of an exothermic reaction between a neutralising agent and either sulphonic acid (ex LAB, alpha-olefins, FAME) or acid sulphate (ex primary alcohols, ethoxylated alcohols). Neutralisation can be carried out after prolonged storage, if the acid stability permits (LABSA, FAME-SA). 

Primary alcohol ethoxysulphates, lauryl ether sulphates (LES) quality, storage, handling and safety... 

Chemithon are known to have "tandem" sulphonated mixtures of alkylbenzene/primary alcohols. The process is similar to the normal operation. In the first loop 20% oleum and alkylbenzene are dosed, in the second loop (the diluter) the alcohol with extra oleum is introduced, followed by immediate neutralisation (see figure 54). A product mix of ABS/alcohol sulphate/sodium sulphate is finally obtained. 

Sodium lauryl sulphate, B.P, is a mixture of sodium normal primary alkyl sulphates and can be assayed by the anionic-cationic titration method. The official method requires weighing of the alcohols liberated on hydrolysis it is inadvisable to dry the residue at 105° and is preferably dehydrated by rapid evaporation with small quantities of dry acetone. 

The lower members of the homologous series of 1. Alcohols 2. Aldehydes 3. Ketones 4. Acids 5. Esters 6. Phenols 7. Anhydrides 8. Amines 9. Nitriles 10. Polyhydroxy phenols 1. Polybasic acids and hydro-oxy acids. 2. Glycols, poly-hydric alcohols, polyhydroxy aldehydes and ketones (sugars) 3. Some amides, ammo acids, di-and polyamino compounds, amino alcohols 4. Sulphonic acids 5. Sulphinic acids 6. Salts 1. Acids 2. Phenols 3. Imides 4. Some primary and secondary nitro compounds oximes 5. Mercaptans and thiophenols 6. Sulphonic acids, sulphinic acids, sulphuric acids, and sul-phonamides 7. Some diketones and (3-keto esters 1. Primary amines 2. Secondary aliphatic and aryl-alkyl amines 3. Aliphatic and some aryl-alkyl tertiary amines 4. Hydrazines 1. Unsaturated hydrocarbons 2. Some poly-alkylated aromatic hydrocarbons 3. Alcohols 4. Aldehydes 5. Ketones 6. Esters 7. Anhydrides 8. Ethers and acetals 9. Lactones 10. Acyl halides 1. Saturated aliphatic hydrocarbons Cyclic paraffin hydrocarbons 3. Aromatic hydrocarbons 4. Halogen derivatives of 1, 2 and 3 5. Diaryl ethers 1. Nitro compounds (tertiary) 2. Amides and derivatives of aldehydes and ketones 3. Nitriles 4. Negatively substituted amines 5. Nitroso, azo, hy-drazo, and other intermediate reduction products of nitro com-pounds 6. Sulphones, sul-phonamides of secondary amines, sulphides, sulphates and other Sulphur compounds... 

The importance of the determination of sulphuric acid and sulphates lies very largely in the fact that sulphur in various forms of combination, and also free sulphur, is frequently determined quantitatively by primary conversion into sulphuric acid or sulphate, followed by actual estimation in the latter form. For example, a convenient volumetric process applicable to the Carius method for determining sulphur in organic compounds is to neutralise the solution of sulphuric acid after removal of the excess of nitric acid by evaporation, and then add silver nitrate, by which the sulphate is converted into silver sulphate. This is separated from the excess of silver nitrate by means of its insolubility in alcohol, and is then estimated by dissolving in dilute nitric acid and titrating the silver with standard thiocyanate solution.3... 

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