Carbon chain length

Because the higher alcohols are made by a number of processes and from different raw materials, analytical procedures are designed to yield three kinds of information the carbon chain length distribution, or combining weight, of the alcohols present the purity of the material and the presence of minor impurities and contaminants that would interfere with subsequent use of the product. Analytical methods and characterization of alcohols have been summarized (13). 

Most of the detergent range alcohols used commercially consist of mixtures of alcohols, and a wide variety of products is available. Table 6 shows the approximate carbon chain length composition of both the commonly used mixtures and single carbon materials typical properties are given ia Table 7. 

Solutions of NaBH in methanol, and to a lesser degree ethanol, are subject to a similar decomposition reaction that evolves hydrogen these solutions can be stabilized by alkaU. The solubiUty of NaBH in lower aUphatic alcohols decreases as the carbon chain length increases, but the stabiUty increases. Solutions in 2-propanol and /-butanol are stable without alkaU (22,24). 

Butane. The VPO of butane (148—152) is, in most respects, quite similar to the VPO of propane. However, at this carbon chain length an important reaction known as back-biting first becomes significant. There is evidence that a P-dicarbonyl intermediate is generated, probably by intramolecular hydrogen abstraction (eq. 32). A postulated subsequent difunctional peroxide may very well be the precursor of the acetone formed. 

Olefins, Diolefins, and Acetylenes. Members of this category having up to four carbon atoms are both asphyxiants and anesthetics, and potency for the latter effect increases with carbon chain length. Skin-contact effects are similar to those of paraffins. 

Fatty acids are represented as x y, where AT is the carbon chain length andjy is the number of double bonds. ... 

DiisononylPhthalate andDiisodeeylPhthalate. These primary plasticizers are produced by esterification of 0x0 alcohols of carbon chain length nine and ten. The 0x0 alcohols are produced through the carbonylation of alkenes (olefins). The carbonylation process (eq. 3) adds a carbon unit to an alkene chain by reaction with carbon monoxide and hydrogen with heat, pressure, and catalyst. In this way a Cg alkene is carbonylated to yield a alcohol a alkene is carbonylated to produce a C q alcohol. Due to the distribution of the C=C double bond ia the alkene and the varyiag effectiveness of certain catalysts, the position of the added carbon atom can vary and an isomer distribution is generally created ia such a reaction the nature of this distribution depends on the reaction conditions. Consequendy these alcohols are termed iso-alcohols and the subsequent phthalates iso-phthalates, an unfortunate designation ia view of possible confusion with esters of isophthaUc acid. 

The major source of raw materials for the preparation of fatty amines is fats and oils such as tallow, and coconut, soya, and palm oils. Ethyl Corporation uses petrochemicals as raw materials to prepare alkyl dimethyl and dialkylmethyl tertiary fatty amines, trademarked as AE)MA and DAMA products, which can be suppHed as single-carbon chain-length cuts or custom blends (13). Commercially available high purity fatty amines are Hsted in Table 3. Cost of the amines can vary owing to supply of raw materials. 

The thermal glass-transition temperatures of poly(vinyl acetal)s can be determined by dynamic mechanical analysis, differential scanning calorimetry, and nmr techniques (31). The thermal glass-transition temperature of poly(vinyl acetal) resins prepared from aliphatic aldehydes can be estimated from empirical relationships such as equation 1 where OH and OAc are the weight percent of vinyl alcohol and vinyl acetate units and C is the number of carbons in the chain derived from the aldehyde. The symbols with subscripts are the corresponding values for a standard (s) resin with known parameters (32). The formula accurately predicts that resin T increases as vinyl alcohol content increases, and decreases as vinyl acetate content and aldehyde carbon chain length increases. 

The physical and chemical properties of chlorinated paraffins are deteanined by the carbon chain length of the paraffin and the chlorine content. This is most readily seen with respect to viscosity (Fig. 1) and volatiUty (Fig. 2) increasing carbon chain length and increasing chlorine content lead to an increase in viscosity but a reduction in volatiUty. 

Paraffin carbon chain length Nominal chlorine contents, %w / w Color hazen (APHA) Viscosity, mPa-s (=cP) Density, g/mL Thermal stability, %w/wHCl Volatihty, %w/w Refractive index... 

Toxicity. The acute toxicity of chlotinated paraffins has been tested ia a range of animals and was found to be very low (4). A comprehensive study (5) demonstrated that the toxicity of chlotinated paraffins was related to carbon chain length and to a lesser degree chlorine content. The shorter chain-length chlotinated paraffins were more toxic than the longer chain chlotinated paraffins. 

Environmental. In general, chlorinated paraffins biodegrade the rate is determined by chlorine content and carbon chain length. Microorganisms previously acclimatized to specific chlorinated paraffins show a greater ability to degrade the compounds than nonacclimatized organisms. Mammals and fish have been shown to metabolize chlorinated paraffins (8). 

Within a series with a fixed hydrophilic head group, detergency increases with increasing carbon chain length, reaches a maximum, and then decreases. This behavior frequentiy reflects a balance between increased surface activity of the monomer and decreased monomer concentration with increased surface activity. Similar effects are seen in surfactants in biological systems. 

Chlorinated paraffins of average carbon chain length Cl 2 and average degree of chlorination approximately 60%... 

The effect of carbon chain length and high vs. low 2-phenyl isomer distribution on viscosity and solubility (cloud/clear point) of a liquid hand dishwashing formulation is shown in Table 5. Two sets of pure LAS homolog samples ranging from Cl0 to Cl3 were prepared. All samples were prepared with pure olefins, but one set was produced with an HF alkylation catalyst (low 2-phenyl) and the other set was alkylated with A1C13 (high 2-phenyl). Each LAB... 

Table 7 gives the apparent CMC and Ksp values for C12 LAS [28]. As carbon chain length increases, the Ksp decreases, which is an indication that the LAS becomes more sensitive to water hardness [27]. It has been reported that the internal phenyl isomers of C,2 LAS are more sensitive to precipitation with Ca2+ than the 2-phenyl isomer [29]. This is presumably due more to the lower CMC of the 2-phenyl LAS isomer than to any increase in the Ksp. 

As the example indicates, these liquids contained a complex mixture of surfactant actives. The LAS used in these products was of higher molecular weight (C,2 5-i3 average carbon chain length) than previous laundry liquids. Typical LAS active levels were 12% or less, presumably due to solubility constraints. 

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. 

Chain length distribution (mean carbon chain length 15) [Pg.149]

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. 

Surfactant alcohols are linear, primary alcohols with carbon chain lengths in the C12-C14 and the C16-C18 range. Surfactant alcohols can be derived from either petrochemical or oleochemical feedstocks, and thus are referred to either as synthetic alcohols or as natural (oleochemical) alcohols. Petrochemical feedstocks used for surfactant alcohol production are ethylene and, to a lesser degree, paraffins. 

As the name suggests, LABs consist of a benzene nucleus to which an alkyl chain is bound. The alkyl chain shows a distribution of carbon chain lengths dependent on the cut of the starting material, while point of attachment to the benzene ring (phenyl isomer distribution) is governed to a large extent by the manufacturing process. 

The physical detergency and biodegradation characteristics of primary alcohols are affected by the carbon chain length distribution. Therefore each new supply may require testing to determine whether the desired properties in the chosen application can be achieved. Examples of guideline specifications are presented in Table 10. 

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