Surfactant production, intermediates olefins

Surfactants can be produced from both petrochemical resources and/or renewable, mostly oleochemical, feedstocks. Crude oil and natural gas make up the first class while palm oil (+kernel oil), tallow and coconut oil are the most relevant representatives of the group of renewable resources. Though the worldwide supplies of crude oil and natural gas are limited—estimated in 1996 at 131 X 1091 and 77 X 109 m3, respectively [28]—it is not expected that this will cause concern in the coming decades or even until the next century. In this respect it should be stressed that surfactant products only represent 1.5% of all petrochemical uses. Regarding the petrochemically derived raw materials, the main starting products comprise ethylene, n-paraffins and benzene obtained from crude oil by industrial processes such as distillation, cracking and adsorption/desorption. The primary products are subsequently converted to a series of intermediates like a-olefins, oxo-alcohols, primary alcohols, ethylene oxide and alkyl benzenes, which are then further modified to yield the desired surfactants. 

Olefins. Olefin is a key surfactant intermediate produced by thermal or catalytic cracking of paraffin or alternatively from oligomization of ethylene. Olefins suitable for surfactant production are primarily linear with either terminal (a-olefins) or internal (i-olefins) double bonds. 

Fatty Amines. A variety of different fatty amines is used as intermediates for surfactant production. Primary amines are used to prepare alkoxylated amines. The primary amine is produced by reacting fatty acid with ammonia to form the nitrile followed by hydrogenation. Tertiary amines are used as an intermediate for producing betaine, amine oxide, and hydroxyl ethyl quat (HEQ). The tertiary amine is produced by reacting olefin with HBr followed by substitution with dimethylamine. 

LAB is derived exclusively from petroleum- or natural gas-based feedstocks. Thus, it is referred to as a petrochemical (or synthetic) surfactant intermediate. Feedstocks for LAB production are generally paraffins (carbon chain length in the range of C8-C14) derived from kerosene and benzene. Internal olefins derived from ethylene are sometimes used in place of paraffins. 

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. 

Intermediates and causes them to abstract hydride Ions more rapidly from Isobutane or any other potential donor. Increased hydride transfer converts more of the carbonlum Ions at the add Interface to saturates faster, yielding product while minimizing polymerization and side reactions. It Is also likely that the surfactants physically block alkyl Ions from one another in the surface film and thus Impede Ion + olefin polymerization. In such a film the carbonlum Ion concentration must also be lower than In the absence of surfactant and mass law effects will therefore also lead to less polymerization and cracking. The fact that steady state hydride transfer rates In H2SO are subject to control through the use of acid modifiers which act In the bulk acid and at the acid-hydrocarbon Interface Is the key to the control of sulfuric acid alkylation. 

Methylated cyclodextrins promote the hydroformylation of higher olefins, too. Molecular dynamics simulations show that the reaction takes place right at the interface and that cyclodextrins act as both surfactants and receptors that favour the meeting of the catalyst and the olefin. The methylated cyclodextrin adopts specific amphiphilic orientations at the interface, with the wide rim pointing towards the water phase. This orientation makes easier the formation of inclusion complexes with the reactant (1-decene), the key reaction intermediate [Rh(H)CO(TPPTS)2-decene)] and the reaction product (undecanal). ... 

The alkylation of benzene with linear olefins (Cj(,-Cj4) is largely used industrially to produce linear alkylbenzenes (LABs), precursors ofalkylbenzenesulfonates which are employed as surfactants and detergent intermediates. LAB global demand is about 2.7 million metric tons per year. Traditional processes are catalyzed by acid catalysts such as AlClj and mainly HF. The processes are designed to minimize skeletal isomerization of the linear olefins since high linearity is necessary to yield biodegradable products [31). In order to improve the sustainability of these processes, various solid acids have been developed. The use of ILs is one of the possibilities to consider. 

Organic residual components are the most worrying because of their toxicity. Some of these compounds are formed as by-products. Volatile organic compounds are determined by headspace GC, GC-MS. Intermediate products, such as sultones and sulfones, from sulfonation of olefin and alkyl-benzene, respectively, can be detected by LC. Unreacted products, like ethylene oxide from the synthesis of ethoxylated nonionic and anionic surfactants, are studied by GC benzyl chloride from the quaternization of tertiary amines and aliphatic amines from amidation reaction are determined by LC (Figure 5). 

Higher n-olefins of Cs-Ci4 are used as intermediates in the manufacture of several types of surfactant materials. Linear internal olefins are used in the production of linear alkylbenzene alkylphenol detergent alcohols, which in turn is used to produce alcohol sulfates, alcohol ethoxylates, and alcohol ether sulfates and synthetic lubricants. a-Olefins are used in the production of detergent alcohols, linear alkylbenzene, synthetic lubricants, and a-olefin sulfonates (another ionic surfactant). 

Improved catalysis of styrene epoxidation by protein-polyion films was related to their better mechanical stability compared to the surfactant films. Product stereochemistry for the epoxidation of cw- 3-methylstyrene depended on oxygen availability. There appear to be two pathways for olefin oxidation. The stereoselective pathway utilizes the high valent iron-oxygen intermediate (Figure 24), as does the natural enzyme system. The non-stereoselective pathway may involve a peroxyl radical near the protein surface that forms in the presence of oxygen [91]. The competing reactions are summarized in Figure 26. 

Hydroformylation of olefins, especially long-chain ones, in aqueous systems with hydrophilic catalysts has another specific feature, not relevant for reactions in anhydrous media. As is evident from the generally adopted scheme of the catalytic process (Scheme 5.12), the intermediates are typical amphiphilic compounds, being built of a lipophilic part from the olefin and a hydrophilic part from the ligand. The products of reaction, long-chain aldehydes, also possess a certain degree of amphiphilicity in aqueous media. Thus, it is evident that interfacial effects associated both with the influence of added surfactants and with the amphiphilic properties of the species involved in the reaction must have a strong influence on hydroformylation in aqueous media. 

Propylene-derived alkyl benzenes were pretty much phased out in the 1960s because of their exceptional (and undesirable) biological stabUity and were replaced by the linear alkyl benzenes prepared from linear olefins or intermediate chlorinated paraffins. These products, like the tetrapropylenes, have a chain length that may range from Cg to Cie, variously distributed according to the specific preparation procedure and the properties desired in the final surfactant. The nominal carbon values for most commercial products are Cg and Cg alkyl groups. 

---