Ethoxylated 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 ... 

All equipment allows production of 40% active alkylbenzene sulphonate and 30% active sodium lauryl alcohol sulphate products. Normally, the equipment also allows production of other products such as high active (50-60%) all lbenzene sulphonate and 70% AD ethoxylated alcohol sulphates. Specially designed neutralisers of this kind yield products such as 75% AD sodium coconut alcohol sulphate. All these q>tions also hold for the Ballestra Neutrex system discussed in section 5.6.3. 

Control of the level of 1,4-dioxane in the ethoxylated alcohol sulphates is often seen as a good measure of the overall performance of the sulphonation plant. All equipment suppliers have examined the effects of various operating and design parameters on the formation of 1,4-dioxane. 

Tabk.32 Ethoxylated alcohol sulphation and neutralisation - optimal conditions... 

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

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)... 

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

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. 

Raw materials. Feedstocks for ethoxylated alcohols are made from a large number of alcohols and practically every fatty alcohol used to make alkyl sulphates is also ethoxylated to make non-ionic surfactants, or feedstock for ether sulphates. 

Raw materials. The alcohols used in PE manufacture are typically detergent alcohols but shorter chains may also be used. Ethoxylated alcohols, used as non-ionic surfactants in their own right, can also be phosphated to give a surfactant with properties intermediate between non-ionic and sulphated anionic. The provenance of the alcohols has already been covered in detail in the Section 4.2. 

Raw materials. The base materials for ether carboxylates are typically ethoxylated alcohols, although ethoxylated aromatics or alkanolamides may also be used but a wider range of alkyl chains and degrees of ethoxylation are used in ether carboxylates than in ether sulphates. Carbon chains from C4 to C20 and degrees of ethoxylation from 2 to 20 may be combined to give the required properties in the surfactant. 

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. 

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... 

The salts of monoesters of sulphuric acid (mainly known as alkyl sulphates, alcohol sulphates or sulphated higher alcohols and ether sulphates or sulphated ethoxylated alcohols) have been proceeded for tens of years through the competition with alkylbenzenesulphonates and other anionic and nonionic surfactants with respect to the consumer s merits and cost performance. Among other surfactants, the today s world consumption share of alcohol sulphates and ether sulphates is ca. 25 % in household and laundry aids and ca. 20 % in personal care products [81]. The formers are mostly based on sulphates of petrochemical origin whereas the least are more oriented to sulphates from oleochemicals. 

Another way having major industrial importance as far ten years back is the sulphation of alcohols and ethoxylated alcohols with chlorosulphonic acid. The reaction is best carried out at 25-30 °C in batch or flow reactors according to the equation ... 

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). 

Moretti G.F. and Adami I. (1988). R D Dept. Ballestra SpA, Milan, Italy. "Sulphation of ethoxylated alcohols in multitube film reactor Product quality and reaction control for low dioxane content". Paper presented at the 2nd World Surfactant Congress, Paris 24-27 May 1988. 

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) ... 

Alkyl sulphates yield the fatty alcohol. Alkylether and ethoxylated alkylphenol sulphates yield the ethoxylated alcohol and ethoxylated alkylphenol respectively. 

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. 

ISO 6843 [7] deals with the determination of the molecular weight of ethoxylated alcohol and alkylphenol sulphates in raw materials. It includes the following procedure for the extraction of active matter with a mixture of ethyl acetate and butan-l-ol in the ratio 9 1 by volume. This procedure is useful in itself and may be of more general use for extracting surfactants from aqueous solution. 

Extraction of ethoxylated alcohol (by deionisation) gives ether sulphate Fatty acid by petroleum ether extraction and alkali titration (lower ethoxylates also extracted) gives glyceride sulphate Extraction of fatty amine and acid titration (lower ethoxylates also extracted) gives sulphosuccinamate... 

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 ... 

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... 

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

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