Alkanesulfonates alkanesulfonate

Whereas superaeid (HF/BF3, HF/SbF, HF/TaF FS03FI/SbF3, etc.)-eatalyzed hydroearbon transformations were first explored in the liquid phase, subsequently, solid aeid eatalyst systems, sueh as those based on Nafion-H, longer-chain perfluorinated alkanesulfonic acids, fluorinated graphite intercalates, etc. were also developed and utilized for heterogeneous reactions. The strong acidic nature of zeolite catalysts was also successfully explored in cases such as FI-ZSM-5 at high temperatures. 

Sulfonate Esters. These are marketed as efficient and easily processible plasticizers with good resistance to extraction. They are typically aryl esters of a to alkanesulfonic acid. 

Fluorinated and Ghlorfluorinated Sulfonic Acids. The synthesis of chlorinated and fluorinated sulfonic acids has been extensively reviewed (91,92). The Hterature discusses the reaction of dialkyl sulfides and disulfides, sulfoxides and sulfones, alkanesulfonyl haHdes, alkanesulfonic acids and alkanethiols with oxygen, hydrogen chloride, hydrogen fluoride, and oxygen—chloride—hydrogen fluoride mixtures over metal haHde catalysts, such as... 

Workup of the complex reaction mixture was difficult and expensive. As a result, these surfactants have been withdrawn from the U.S. market. In Europe, Hoechst AG produces secondary alkanesulfonates by a similar reaction (eq. 12) ... 

Tetrabutylammonium iodide in trifluoroacetic anhydride is an effective reducing reagent [dS] This system can be used for direct reduction of arenesulfonic acids to the corresponding thiols or disulfides m moderate yields under mild conditions (equation 18) Alkanesulfonic acids are reduced by this system to disulfides with 30-57% yields [dfi]... 

Sodium alkanesulfonates for detergent manufacture can also be produced from the free-radical addition of sodium bisulfite and alpha olefins ... 

Alkanesulfonates are the petrochemically derived sulfur analogs of soaps, which are alkane carboxylates based on renewable resources. The main difference between alkanesulfonates and soaps is, however, that alkanesulfonates consist of a rather complex mixture of homologs with different carbon chain lengths and isomers with an almost statistical distribution of the functional group along the hydrophobic carbon chain (Fig. 1), whereas soap is a mixture of homologs of alkane 1-carboxylates with an even number of carbon atoms. 

Known since the 1940s as commercial products, alkanesulfonates have attracted much interest and are valued as anionic surfactants, both for household and industrial uses. Because of the strong carbon-sulfur bond, alkanesulfonates are appropriate surfactants for applications in acidic and alkaline media. 

Due to their favorable solubility, alkanesulfonates are preferred as surfactants in liquid products and concentrates. The recent trend to renewable resources has led to a somewhat reduced use in formulations of household detergents in past years. While some manufacturers have withdrawn these surfactants from, for example, manual dishwashing detergents, others did not. Besides many other industrial applications, alkanesulfonates are one of the most important emulsifiers in vinyl polymerization. 

Table 1 gives the production capacities of known installations for alkanesulfonates according to the two established manufacturing routes. It is noticeable that most alkanesulfonate capacities are located in Europe and some in the Far East. No installation is known in the Americas. 

There are two technical routes to the manufacture of alkanesulfonates sulfoxidation and sulfochlorination [1,2]. The sulfoxidation route is the economically more important one, and new plants are based exclusively on this tech-... 

The extract consists of alkanesulfonic acid, sulfuric acid, paraffin, water, and dissolved sulfur dioxide. After degassing to remove the sulfur dioxide (3), the extract has approximately the composition given in Table 2. 

In a falling film evaporator (4) a water-paraffin mixture is distilled off and completely pumped back to the reactor. The resulting product is separated into a 60% sulfuric acid fraction and paraffin-containing alkanesulfonic acid (5), which is bleached by hydrogen peroxide (6). In a stirred vessel (7) the alkanesulfonic acid is neutralized by 50% sodium hydroxide solution until the pH is exactly 7. The composition of the neutralized product is also given in Table 2. 

At 220°C a water-paraffin mixture is distilled off in a circulating evaporator (8). The product mixture passes to a second circulating evaporator (9) where the paraffin is stripped at 270°C with overheated water vapor, and finally the paraffin content in the resulting alkanesulfonate melt is further reduced by vapor stripping in a packed column (10). A heat transfer oil dissipates excess heat. 

The alkanesulfonate melt is treated with 4 bar of water to give a paste containing 60% active matter (12) or pelletized by means of a cooling conveyor with a special feeding device (not shown in Fig. 2). The solid product is composed of 93 wt % of alkanesulfonate, 6 of sodium sulfate, and 1 of paraffin. 

The byproduct is a stoichiometric amount of 60 wt % H2S04, which is used in the chemical industry. The wastewater (0.3 m3/100 kg active matter), which contains paraffin, oxidation products of the paraffin, alkanesulfonate, and sulfur dioxide, has a chemical oxygen demand (COD) of 1800 mg/L and is readily biodegradable (>95% after 7 days). The sulfur dioxide emission after repeated washing of the off-gas amounts to 0.5 g/100 kg active matter [6]. 

TABLE 4 Specifications of Sulfoxidation-Derived Alkanesulfonates (Hostapur SAS 60)... 

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