Paraffinic hydrocarbons chlorination

Chlorinated paraffins Hydrocarbons chlorinated to a level of 40-50%. Have some compatibility constraints and can influence heat stability Used in conjunction with primary plasticisers to give volume cost savings. Chlorine content improves flame retardancy... 

The substance is examined in a dilute solution in a solvent. A wide choice of solvents, transparent to ultraviolet radiation, is available. The paraffin hydrocarbons are all suitable, as are the ahphatic alcohols and the chlorinated hydrocarbons, such as chloroform and carbon tetrachloride. The most useful solvents are re-hexane, cycZohexane, chloro-... 

The most important olefins used for the production of petrochemicals are ethylene, propylene, the butylenes, and isoprene. These olefins are usually coproduced with ethylene by steam cracking ethane, LPG, liquid petroleum fractions, and residues. Olefins are characterized by their higher reactivities compared to paraffinic hydrocarbons. They can easily react with inexpensive reagents such as water, oxygen, hydrochloric acid, and chlorine to form valuable chemicals. Olefins can even add to themselves to produce important polymers such as polyethylene and polypropylene. Ethylene is the most important olefin for producing petrochemicals, and therefore, many sources have been sought for its production. The following discusses briefly, the properties of these olefmic intermediates. 

As mentioned in Chapter 2, methane is a one-carhon paraffinic hydrocarbon that is not very reactive under normal conditions. Only a few chemicals can he produced directly from methane under relatively severe conditions. Chlorination of methane is only possible by thermal or photochemical initiation. Methane can be partially oxidized with a limited amount of oxygen or in presence of steam to a synthesis gas mixture. Many chemicals can be produced from methane via the more reactive synthesis gas mixture. Synthesis gas is the precursor for two major chemicals, ammonia and methanol. Both compounds are the hosts for many important petrochemical products. Figure 5-1 shows the important chemicals based on methane, synthesis gas, methanol, and ammonia. ... 

Higher paraffinic hydrocarbons than methane are not generally used for producing chemicals by direct reaction with chemical reagents due to their lower reactivities relative to olefins and aromatics. Nevertheless, a few derivatives can be obtained from these hydrocarbons through oxidation, nitration, and chlorination reactions. These are noted in Chapter 6. 

Sometimes, addition of plasticizer imparts flame retardant characteristics in addition to other properties. Phosphate esters such as tris(2-ethyl hexyl) phosphate (TOP), tricresyl phosphate (TCP), chlorinated paraffin hydrocarbons etc. impart excellent flame retardant characteristics to many polymers. 

Carbon tetrachloride represents an example of the change to petroleum raw materials in this field. The traditional source of this widely used product has been the chlorination of carbon disulfide, either directly or through the use of sulfur dichloride. Military requirements in World War II caused an increase in demand, and in addition to expansion of the older operations, a new process (28) was introduced in 1943 it involved direct chlorination of methane at 400° to 500° C. and essentially atmospheric pressure. This apparently straight-forward substitution of halogen for hydrogen in the simplest paraffin hydrocarbon was still a difficult technical accomplishment, requiring special reactor construction to avoid explosive conditions. There is also the fact that disposal of by-product hydrochloric acid is necessary here, though this does not enter the carbon disulfide picture. That these problems have been settled successfully is indicated by the report (82) that the chlorination of methane is the predominant process in use in the United States today, and it is estimated that more than 100,000,000 pounds of carbon tetrachloride were so produced last year. 

The reaction of sulfur dioxide and chlorine with paraffin hydrocarbons to yield alkane sulfonyl chlorides (RH + S02 + Cl2 - RS02C1 + HC1) (the Reed reaction) was patented in 1939.221 This reaction has usually been run in the liquid phase under strong illumination with short wavelength visible or ultraviolet light.107,218 267... 

Halogenated hydrocarbons Chlorinated paraffins naphthalenes Chlorowax Halo wax Seekay wax Diamond Alkali Co Union Carbide Carbon Co ICI... 

The majority of secondary plasticizers in use are chlorinated paraffins, which are hydrocarbons chlorinated to a level of 30—70%. For a given hydrocarbon chain, viscosity increases with chlorine content, as does the fire retardancy imparted to the formulation. These materials aid fire retardancy due to their chlorine content. Chlorinated paraffins of the same chlorine content may, however, have different volatilities and viscosities if they are based on different hydrocarbon chains (see Chlorocarbons and chlorohydrocarbons, chlorinated paraffins). 

During maintenance work, simultaneous release of chlorine and acetylene from two plants into a common vent line leading to a flare caused an explosion in the line [10]. The violent interaction of liquid chlorine injected into ethane at 80°C/10 bar becomes very violent if ethylene is also present [11]. The relationship between critical pressure and composition for self-ignition of chlorine—propane mixtures at 300°C was studied, and the tendency is minimal for 60 40 mixtures. Combustion is explosive under some conditions [12]. Precautions to prevent explosions during chlorination of solid paraffin hydrocarbons are detailed [13]. In the continuous chlorination of polyisobutene at below 100°C in absence of air, changes in conditions (increase in chlorine flow, decrease in polymer feed) leading to over-chlorination caused an exotherm to 130°C and ignition [14],... 

As their name implies, chlorinated paraffins are chlorinated derivatives of paraffinic hydrocarbons. They are referred to in this review as polychlorinated alkanes (PCAs) because they are produced by chlorination of n-alkane feedstocks. Commercial PCA mixtures fall into different categories C10-C13 (short), C 4-C17 (medium) and C2o-C30 (long). These mixtures are further subcategorized into their weight content of chlorine 40-50%, 50-60%, and 60-70% [1,2]. Knowledge of the environmental chemistry of PCAs is needed because the physical properties of short and medium chain mixtures are similar to those of the... 

Concurrently with the preliminary arrangement of source materials, a list of key words is compiled for use in checking the abstract journals—for example, although Chemical Abstracts has a fine subject index, the searcher must nevertheless look under a number of headings. In the case of the chlorination of methane, one cannot rely solely on the entries under methane and chlorination, but must check halogenation, paraffins, hydrocarbons, natural gas, and all the products that might be obtained by the reaction. 

Properties Pale-yellow crystals containing not less than 28% nor more than 30% active chlorine. Chlorine odor stable when pure, decomposed slowly by air, rapidly by impurities, petrolatums, kerosene, olive oil, and alcohol. Soluble in glacial acetic acid, chlorinated paraffin hydrocarbons, eucalyptol, benzene, chloroform, and carbon tetrachloride almost insoluble in water mp 80C. 

Properties Amber liquid. Bp 156-157C (0.2 mm Hg). Slightly soluble in water miscible with paraffin hydrocarbon, aromatic hydrocarbon, and chlorinated hydrocarbon solvents. 

The chlorination of paraffinic hydrocarbons has received more attention than that of any of the other groups. An excellent review of this phase was presented by Asinger (15). Several other surveys (36, 42, 72) are available. 

Oxidation of all the saturated paraffin hydrocarbons up to isobutane in the presence of chlorine was found to result in the preferential reaction of the oxygen with the carbon to give carbon dioxide and of the chlorine with hydrogen to give hydrochloric acid gas.1- ... 

Prisms from chloroform + petr ether, mp 83". Strong chlorine odor dec on exposure to air with loss of chlorine, mp about 80". Almost insol in water, dec by alcohol when warmed one gram dissolves in about 1 ml benzene, 1 ml chloroform, 2.5 ml carbon tetrachloride sol in eucatyptol, chlorinated paraffin hydrocarbons, glacial acetic acid slightly sol in perr ether. Keep well closed and protected from light. USE Germicide. thexap cat Antibacterial. 

By the use of these graphs, an approximation may be made of the isomeric monochloride compositions obtained by chlorination of a number of paraffin hydrocarbons. 

In a chain reaction, once a source of energy activating the chlorine has been applied, the rate of reaction of chlorine gas with vapors of paraffin hydrocarbons is a function of the molar composition of the mixture. Within certain limits this reaction will become so rapid that inflammation of the mixture will occur because of lack of heat dissipation, and within still narrower limits the flame velocity will increase into detonation rates. An approximate range for these limits of propane and chlorine is presented in Fig. 6-4. 

Treatment of Paraffin Hydrocarbons. Sulfuryl chloride reacts readily with unsaturated hydrocarbons to form the halogen derivatives. It can also be employed to advantage in the chlorination of saturated paraffins, such as methane, hexane, and octadecane. 

In general, methods similar to chlorination with chlorine and chlorides can be employed in the preparation of bromine derivatives. Because the reaction is milder, the bromination of the paraffin hydrocarbons does not, however, proceed so rapidly or to so great a degree and with the lower permissible operating temperature, the formation of polybromine compounds occurs to a lesser extent. 

Fia. 6-10. Plant layout for chlorination of pentane and other paraffin hydrocarbons. 

The chlorination of paraffin hydrocarbons has been studied recently with the hope that natural gas and petroleum might prove a source for halogen derivatives of value in the arts. It has been shown, for example, that when a mixture of 5 volumes of methane and 4 volumes chlorine is heated to about 280" and passed over clay covered with aluminium chloride, there can be attained from 1000 cubic feet of the hydrocarbon about 50 pounds of carbon tetrachloride and 190 pounds of chloroform. Since natural gas contains methane and ethane the method may prove of value industrially for the preparation of the chlorine substitution-products of the hydrocarbons. If the chlorination can be controlled to give a high percentage of methyl chloride and if a way can be found to hydrolyze the latter in a satisfactory way to methyl alcohol the reactions will be of technical interest in the preparation of this important alcohol. 

Properties Gardner 16 color (50% in 100 solv.) sol. in chlorinated hydrocarbons, esters, ethers, ketones (except acetone), aromatic, naphthenic, and terpene hydrocarbons partially sol. in paraffinic hydrocarbons insol. in alcohols m.w. 405 soften, pt. (R B) 105 C iodine no. 150 Precaution Incompat. with alkyds short oil and cellulose derivs. LX -1082 [Neville]... 

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