Alkylphenol ethoxylate phenol

Alkylphenol. Alkylphenol is a common surfactant intermediate used to produce alkylphenol ethoxylates. Phenol reacts with an olefin thermally without a catalyst but with relatively poor yields. Catalysts for the reaction include sulfuric acid p-toluene sulfonic acid (PTSA), strong acid resins, and boron trifluoride (BF3). Of these, strong acid resins and BF3 are mostly widely used for the production of surfactant-grade alkylphenols. The most common alkylphenols are octylphenol, nonylphenol, and dodecylphe-nol. Mono nonylphenol (MNP) is by far the most common hydrophobe. It is produced by the alkylation of phenol with nonene under acid conditions. All commercially produced MNP is made with nonene based on propylene trimer. Because of the skeletal rearrangements that occur during propylene oligomerization, MNP is a complex mixture of branched isomers. 

Commercial alkylphenol ethoxylates are almost always produced by base-cataly2ed ethoxylation of alkylphenols. Because phenols are more strongly acidic than alcohols, reaction with ethylene oxide to form the monoadduct is faster. The product, therefore, does not contain unreacted phenol. Thus, the distribution of individual ethoxylates in the commercial mixture is narrower, and alkylphenol ethoxylates are more soluble in water. 

Di- and Triisobutylcncs. Diisobutylene [18923-87-0] and tnisobutylenes are prepared by heating the sulfuric acid extract of isobutylene from a separation process to about 90°C. A 90% yield containing 80% dimers and 20% trimers results. Use centers on the dimer, CgH, a mixture of 2,4,4-trimethylpentene-1 and -2. Most of the dimer-trimer mixture is added to the gasoline pool as an octane improver. The balance is used for alkylation of phenols to yield octylphenol, which in turn is ethoxylated or condensed with formaldehyde. The water-soluble ethoxylated phenols are used as surface-active agents in textiles, paints, caulks, and sealants (see Alkylphenols). 

FD-MS is also an effective analytical method for direct analysis of many rubber and plastic additives. Lattimer and Welch [113,114] showed that FD-MS gives excellent molecular ion spectra for a variety of polymer additives, including rubber accelerators (dithiocar-bamates, guanidines, benzothiazyl, and thiuram derivatives), antioxidants (hindered phenols, aromatic amines), p-phcnylenediamine-based antiozonants, processing oils and phthalate plasticisers. Alkylphenol ethoxylate surfactants have been characterised by FD-MS [115]. Jack-son et al. [116] analysed some plastic additives (hindered phenol AOs and benzotriazole UVA) by FD-MS. Reaction products of a p-phenylenediaminc antiozonant and d.v-9-lricoscnc (a model olefin) were assessed by FD-MS [117],... 

Nonionic Polyoxyethylenated alkyl-phenols, alkylphenol ethoxylates Emulsifying agents Generally water-soluble Good chemical stability... 

Nonionic surfactants contain (Fig. 23) no ionic functionalities, as their name implies, and include ethylene oxide adducts (EOA) of alkylphenols and fatty alcohols. Production of detergent chain-length fatty alcohols from both natural and petrochemical precursors has now increased with the usage of alkylphenol ethoxylates (APEO) for some applications. This is environmentally less acceptable because of the slower rate of biodegradation and concern regarding the toxicity of phenolic residues [342]. 

Alkylphenol Ethoxylates (APE). The hydrophobes of most commercial APE are made by reacting phenol with either propylene trimer or diisobutylene to form nonylphenol or octylphenol. These products contain an aromatic moiety and extensive branching in their alkyl chains. It has been shown that APE biodegrade more slowly and less extensively than LPAE (3.15-20). The difference is more pronounced when the treatment system is operating under stress conditions such as low temperatures and high surfactant loadings. 

Important classes of nonionic surfactants are aliphatic poly-ethoxylate alcohols (AEO), and octyl or nonyl phenol polyethoxylates (OPEO and NPEO). The alkylphenol ethoxylates (APEO) attracted special attention due to their supposedly endocrine disrupting properties (Ch. 8.3). LC-MS analysis may also involve nonylphenolethoxycarboxylates (NPEC), biodegradation products of NPEO, and halogenated analogues, generated in chlorine disinfection treatments in drinking water production plants. 

Pulp and paper mill sludge is a complex and changeable mixture of dozens or even hundreds of compounds. Some are well known, like natural wood extractives, organochlorines, organosulfides, and dioxins. Priority pollutants and chemicals of concern that must be analyzed in pulp mill residues include heavy metals, chlorinated hydrocarbons, chlorobenzenes, PAHs, chlorinated phenols, chlorinated catechols, chlorinated guaiacols, phthalates, resin acids, alkylphenols and alkylphenol ethoxylates, and plant sterols. 

Alkylphenol ethoxylates are important kinds of nonionic surfactants. A characteristic feature of the catalytic ethoxylation of alkylphenols is the enhanced reactivity of phenol hydroxyl for ethylene oxide in comparison with alcohols. Esters of ethylene glycol and alkylphenol behave already as an alcohol. Therefore di-, tri-, and m-mers are allowed to form only after the complete consumption of the starting material. All commercial ethoxylated alkylphenols are mixtures of oligomer-homologues having a Poisson-like distribution with some PEG and catalyst as impurities. Both alkylphenols and dialkylphenols are useful for ethoxylation as a hydrophobic moiety. Among the alkylphenols, isooctylphenol and isononylphenol are most widely used. They are synthesized by the Friedel-Crafts alkylation of phenol with butene dimer and mixture of propene trimers, respectively. 

GC has been applied to the determination of several alkylphenols. The determination of 4-nonyl-phenol (4-NP) in effluent and sludge from sewage treatment plants has been shown while alkylphenol ethoxylates have been determined in industrial and environmental samples using GC-MS. 

Alkylphenol ethoxylates (APE) used in phenolic resin and as an additive (annual world production - 0.07 MMT)... 

A source of error in the HPLC method is the very short retention time of PEG in reversed-phase systems. This makes quantification by differential refractive index subject to interference by peaks from water, solvent impurities, and other unretained substances. This source of error may be eliminated by coupling the HPLC column to a GPC column, so that PEG is resolved from both the surfactant and from other impurities (36). Even with this modification, if phenol impurity were present in the initial alkylphenol, the resulting ethoxylated phenol could interfere with PEG determination by this method. Its presence is detected by using a UV detector in series with the RI detector. Another source of interference is the anion, such as acetate or lactate, added during the neutralization of the catalyst. For careful work, this should be removed by ion exchange prior to HPLC analysis (36). 

Alkylphenol ethoxylate (APE) surfactants make up approximately 10% of overall consumption. While effective in many industrial applications, they face a number of environmental challenges that could greatly reduce their use in the future. Of major importance are questions concerning their relatively slow rate of biodegradation and the possible toxicity of degradation intermediates, especially phenols and other aromatic species. In the United States and western Europe, many detergent manufacturers have voluntarily discontinued their use in household products. 

Equation 20 is the rate-controlling step. The reaction rate of the hydrophobes decreases in the order primary alcohols > phenols > carboxylic acids (84). With alkylphenols and carboxylates, buildup of polyadducts begins after the starting material has been completely converted to the monoadduct, reflecting the increased acid strengths of these hydrophobes over the alcohols. Polymerization continues until all ethylene oxide has reacted. Beyond formation of the monoadduct, reactivity is essentially independent of chain length. The effectiveness of ethoxylation catalysts increases with base strength. In practice, ratios of 0.005—0.05 1 mol of NaOH, KOH, or NaOCH to alcohol are frequendy used. 

Steinle et al. [426] studied the primary biodegradation of different surfactants containing ethylene oxide, such as sulfates of linear primary alcohols, primary oxoalcohols, secondary alcohols, and primary and secondary alkyl-phenols, as well as sulfates of all these alcohols and alkylphenols with different degrees of ethoxylation. Their results confirm that primary linear alcohol sulfates are slightly more readily biodegradable than primary oxoalcohol sulfates and that secondary alcohol sulfates are also somewhat worse than the corresponding linear primary. 

Because alkylphenol has a more acid H atom in the phenolic OH group, the ethoxylation with NaOH or NaOCH3 and other alkaline catalysts gives a narrow range EO distribution. 

Phenolic compounds are used in commercial or consumer products or building materials (Rudel et al., 2001), especially ethoxylated alkylphenols of octylphenol and nonylphenol, which are widely used in surfactants (Ying, Williams and Kookana, 2002). They are known as endocrine disrupting compounds (EDC) as they bear hormonally active properties. Other EDCs found indoors include phthal-ates (Section 11.2.7), certain pesticides, organotin compounds (Section 11.2.5) and polybrominated diphenyl ethers (Section 11.2.8) (Rudel et al., 2001, 2003). 

The alkylphenols behave in the same manner as fatty alcohols. The nonyl (or octyl) phenol is widely used with 8 to 12 molecules of ethylene oxide. Nonylphenol is completely soluble in water at room temperature and exhibits excellent detergency. Dodecylphenol ethoxylate is used in certain agriculture emulsifiers and dinonylphenol as low or nonfoaming ingredients of household washing machine powders [3, 4]. 

Among different nonionic surfactant classes, alkyl-phenol ethoxylates (APEOs) comprise the class meriting special attention with respect to environmental issues. The analysis of underivatized alkylphenolic compounds by GC-MS is restricted to the most volatile degradation products, such as alkylphenols and APEOs with less then 4-ethoxy groups. To overcome the problem of volatility, different offline and online derivatization protocols have been developed. Two complementary MS techniques, one using El and another using the less commonly used positive (P)CI, have been evaluated for the analysis of APEOs, their acidic (APECs) and neutral metabolites (APs), and halogenated derivatives. 

When using MS/MS and more selective multiple reaction monitoring detection, it is recommended that the formation of sodimn adducts is suppresses, as these fragment poorly. ESI-MS/MS permits unambiguous identification and structure elucidation vmder negative ionization conditions of acidic alkyl-phenolic compounds (i.e., APECs) and fully de-ethoxylated alkylphenols. An example of MS/MS spectra of NP and NPjEC is shown in Figure 3. 

The most widely used alkylphenols in the manufacture of nonionic surfactants are described as follows in the order of their importance. APEs derived from p-nonylphenol account approximately 80% of the total market whereas those derived from octyl phenol account for 15-20%. Dodecyl phenol, di-nonylphenol, and DSBP ethoxylates run a poor third at <5%. 

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