Alcohol ethoxylate sulphates

The demister may reduce the formation of dioxane during alcohol ethoxylate sulphation and may also reduce corrosion and fouling at the head of the reactor by reducing the exposure to oleum. The containing vessel of the demister should be hot water traced. The liquor drained from the vessel bottom is a solution containing oleum and iron sulphate. The filter should be installed as close as possible to the reactor top. The gas tube from the SO3 gas generation unit through to the sulphonation reactor should be thermally insulated. 

Ballestra conclude that the 1,4-dioxane content increases dramatically with a slight excess of the SOs/organic mole ratio in each reactor tube and any part of each reactor tube and in the overall process mass balance. Furthermore, 1,4-dioxane levels are affected by the type of base alcohol, the range of ethoxylation and the moisture content in the feedstock. The 1,4-dioxane content in alcohol ethoxylate sulphates in the range with 2-3 EO molecules, can nowadays be... 

It is essential to neutralise the acid forms of lauryl alcohol, alcohol ethoxylates and tallow alcohol as quickly as possible to prevent reversion (see also 4.3.3). To make "standard" concentrations of LABS, lauryl alcohol sulphate, lauryl alcohol ethoxylate sulphate and tallow alcohol sulphate, the following conditions are required (table 39) ... 

Nowadays these compounds are usually blended with other surfactants, including nonionic types (section 9.6). In 1990 a typical low- or non-phosphate domestic detergent contained 7% linear alkylbenzenesulphonate and 6% nonionic fatty alcohol ethoxylate [16]. There is increasing use of the long-chain fatty alcohol poly(oxyethylene) sulphates previously described (e.g. 9.12) as a partial or complete replacement for linear alkylbenzenesulphonates [15] since they are made from renewable feedstocks such as tallow and palm oil [16]. 

Particularly effective is a mixture of anionic and nonionic agents, such as a mildly anionic sulphated alcohol ethoxylate with a nonionic alcohol ethoxylate. Ideally, foaming agents should ... 

Low cost Choose from the following most widely used ones soaps, linear alkylbenzene sulphonates (LABS), alcohol ethoxysulphates (AES), alcohol sulphates (AS), alkane or paraffin sulphonate (SAS), and alcohol ethoxylates (AE)... 

Dishwashing liquids Alkyl benzene sulphonates Alcohol ether sulphates Fatty alcohol ethoxylates Detergency/foaming... 

Hard surface cleaners Alkyl benzene sulphonates Alkanolamides Fatty alcohol ethoxylates Potassium oleic acid sulphonate Shorter chain alcohol ether sulphates Detergency high/low foaming... 

Resin emulsifiers Alkylphenol ether sulphates Fatty alcohol ether sulphates Fatty alcohol ethoxylates Emulsifiers... 

Coco imido dipropionate Fatty alcohol ethoxylates Alkyl sulphates Sodium dialkyl sulpho succinates Wetting agents... 

Sources and properties of alcohol ethoxylates are covered in more detail under alkyl sulphates and alkyl ether sulphates. 

The condensation method begins with molecular units, and the particles are built-up by a process of nucleation typical example is the preparation of polymer lattices, in which case the monomer (e.g., styrene or methylmethacrylate) is emulsified in water using an anionic or nonionic surfactant (e.g., sodium dodecyl sulphate or alcohol ethoxylate). A polymeric surfactant is also added to ensure the long-term colloid stabiHty of the resulting latex. An initiator such as potassium persulphate is then added and, when the temperature of the system has increased, initiation occurs that results in formation of the latex [polystyrene or poly(methylmethacrylate)]. 

Surfactants Ionic, anionic (e.g., sodium dodecyl sulphate, Cj2H250S03 Na ), cationic (e.g., cetyl trimethyl ammonium chloride, Ci,H33-N+(CH3)3C1-), zwitterionic [e.g., 3-dimethyldodecylamine propane sulphonate (betaine CJ2H25-N" (CH3)2-CH2-CH2-CH2-S03)], nonionic, alcohol ethoxylates C H2 +i-0-(CH2-CH2-0) -H, alkyl phenol ethoxylates C H2 +i-CgH4-0-(CH2-CH2-0) -H, amine oxides (e.g., decyl dimethyl amine oxide, C10H21-N ( 113)2 0), and amine ethoxylates. 

Surfactants Alkylbenzene sulphonate, alcohol sulphate alcohol ethoxylate 1 0-25a 18-25 10-25 8-18 25 10... 

Figure 1.1 presents the consumption of the major surfactants in the world market in 1996. Along with soap, linear alkylbenzene sulphonates (LAS) remain the most bulky and cost-effective anionic surfactants. LAS will continue to be the workhorse of the detergents industry on a global basis. However, the LAS share decreases gradually their recess is occupied by alcohol-derived surfactants, first of all alcohol sulphates (AS), alcohol ethoxylates (AE) and alcohol ether sulphates (AES). In West Europe alkylphenol ethoxylates (APE) have been removed over the last two decades from a large number of household applications in view of... 

Data on the preparation of alkyd emulsions by the phase inversion technique were presented in [211]. This technique is accomplished by adding water to an alkyd/surfactant mixture under formation of a stable emulsion. The determination of surfactant s solubility in water and alkyd phases allows to calculate the quantity of water required for phase inversion. Effective emulsifiers are ethoxylated sulphates (2-3 EO groups) of C12 - Ch and C16 - Cig higher alcohols. With these surfactants, the emulsification becomes less dependent on the temperature than with nonionic surfactants. 

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 commonest alcohol ethoxylates found as feedstocks for sulphation have an average of 2 to 3 molecules of ethylene oxide (2EO or 3EO). 

During the sulphation of alcohol ethoxylates the by-product 1,4-dioxane may be formed. Although the formation of 1,4-dioxane is governed predominantly by the sulphation and neutralisation conditions and by the chemical composition of the feedstock, other factors such as the quality of the raw material also contribute. These factors must be considered during the storage and handling of the alcohol ethoxylate feedstock. 

The formation of the by-product 1.4 dioxane during the sulphation of alcohol ethoxylates has prompted a re-appraisal of the required quality standards for this feedstock. Consequently some of the material components which are considered to affect 1.4 dioxane formation should be included when establishing a specification with a supplier. The following information may be used as guideline ... 

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. 

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). 

In the case of alpha-olefins, alcohols and alcohol ethoxylates high levels of decomposition products can also be present, notably high levels of 1,4-dioxane (0.5 - 1.0%) when alcohol ethers are sulphated and the residue remains in its acid form for long periods (hours). Residues from a plant running exclusively on alkylbenzene can be blended with the main production stream at a low level to meet sulphonic acid colour standards. 

These materials are readily determined by two-phase titration (ISO 2271) or potentiometric titration with benzethonium chloride. On acid hydrolysis they yield the corresponding alcohol, a sulphate ion and a hydrogen ion, and this affords three additional approaches—determination of the increase in acidity, of the amount of fatty alcohol or ethoxylated alcohol liberated, and of the sulphate ion. The experimental procedure may be varied within limits for example ISO 2870 [5] and ASTM D 1570-89 [6] differ with respect to the identity of the acid used, duration of boiling, choice of indicator and other details. The following procedures are similar to both of those standard methods. The choice of indicator is immaterial for these particular compounds, but is of crucial importance in some other cases. 

Alternatively, a method is described for alkyl ether sulphates, which would also be applicable to alcohol ethoxylates, in which the equilibrium head-space is analysed on a 3 m x 1.8 mm i.d. column of 0.8% THEED/ Carbopack C (80-100 mesh) [14]. A detection limit with FID of 0.1 ppm is claimed. For improved quantitation, both methods can be adapted to a method of standard additions. 

Alkyl ether sulphates can be analysed on a 2.5 cm x 2 mm i.d. column of CIS reverse phase material with a water/tetrahydrofuran gradient system [20]. In this example the detector was the evaporative light scattering detector, as a gradient system was being used with a molecule with no strong chromophore. Alternatively, to obtain more detailed distributions, the molecule could be desulphated and analysed as described for alcohol ethoxylates. 

A reliable modification of the process for the estimation of methoxyl is that of the British Pharmacopoeia, 1932. The apparatus is shown in Fig. 80. A Pyrex flask (A) of about 100 c.cs. capacity, having a bulb (B) of about 70 c.cs. capacity blown on the side tube, contains the mixture of substance (about 0-2 gm.) and hydriodic acid (10 c.cs.). The side tube is connected through a smaller bulbed tube (0) to a set of bulbs (D, see Fig. 65), immersed in a water bath at 60° (95° for ethoxyl), containing red phosphorus suspended in a 2% aqueous solution of cadmium sulphate. To this is attached two absorption flasks (E), each containing about 20 c.cs. of the above alcoholic silver nitrate. To the flask (A) is... 

Monoester sulphosuccinates use a wider variety of alcohols than diesters and tend to use longer carbon chain alcohols to obtain the required HLB value from a single alkyl group. A typical product for cleansing applications would use a C12-14 alcohol derived from coconut or palm kernel oil. These materials are easily available due to their use as raw materials for sulphation (see later). Effective sulphosuccinates can also be prepared from petrochemical alcohols but these seem to be less popular. Ethoxylated alcohols (typically 3 mol of EO) are also used and can provide additional benefits in personal care applications. In some cases, alkanolamides or ethoxylated alkanolamides are used as the alcohol, such as ethoxylated cocomonoethanolamide, but they are relatively uncommon, since they are difficult to manufacture and are prone to colouration. 

This class of surfactants has possibly the widest range of use of any anionic surfactant. It is found in almost every product where foaming is desirable, in industrial, household and personal care applications. Alkyl ether sulphates are described in terms of their parent alcohol and the degree of ethoxylation. Thus, sodium laureth-2 is the sodium salt of a sulphated (predominantly) C12 alcohol, with an average of 2 mol of ethylene oxide added. Often, the alcohol is assumed to be the typical C12-14 and the surfactant simply called a 2-or 3-mol ether sulphate. 

Chemistry and general properties. The chemistry of ether sulphates is very similar to that of alkyl sulphates. The backbone of the molecule is a fatty alcohol and often the same alcohols are used as feedstocks for alkyl sulphates, and alkyl ether sulphates and, with higher degrees of ethoxylation, as non-ionic surfactants. The ethoxylation process is more fully described in Chapter 5. 

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