Nitro-hydrocarbons properties

The nitro-hydrocarbons are neutral substances but when a nitro-group is introduced into a phenol or amine the acidic properties are greatly increased or the basicity decreased. The presence of a nitro-group also tends to make halogen atoms in the same molecule much more reactive. 

Nitrile offers moderate resistance to abrasion with excellent ability to handle oils and hydrocarbons. A special food grade is available for the food and beverage industry. The properties of nitrile are presented in Table 10-15. Nitrile may be reinforced with heavy nylon fabric for high-pressure hoses. Nitrile is used for seals, fUngers, and screens. It is attacked by ozone, ketones, esters, aldehydes, and chlorinated and nitro-hydrocarbons. 

Hypalon is a tradename for CSM chlorosulfonated polyethylene. It offers good resistance to moderate chemicals, ozone, alkaline solutions, hydrogen. Freon, alcohols, aliphatic hydrocarbons, as well as ultraviolet degradation from sunrays. Strong oxidizing acids, ketones, esters, acetic acid, and chlorinated and nitro-hydrocarbons attack Hypalon. Its temperature range for applications is from -40°C to 150°C (-40°F to 300°F). Its physical properties are presented in Table 10-16. 

Energetic materials with strained or caged structures are often much more difficult to synthesize compared to their open chain counterparts. This presents a further challenge to researchers of new energetic materials - while new compounds can be synthesized on a laboratory scale, and their properties and performance tested, the complexity of the synthetic routes may render their use as explosives nonfeasible. This particularly applies to polynitropolycyclic hydrocarbons because the direct nitration of these hydrocarbons is not a feasible route of introducing nitro groups without considerable decomposition. 

The classes listed in Table 1-12 are families which exhibit the same regularity of boiling points, melting points, densities, and other properties seen in the hydrocarbon families we have already studied. Some of the families are named with characteristic suffixes while others have prefixes, or even separate words-in the names. For instance, alcohols are named with the suffix -ol. Ketones are named with the suffix -one. Amine and nitriles are named with the full suffix according to the family name. Ethers and halides usually have the full family name as a separate word, and nitro- and organometallic compounds have the prefix nitro- or the prefix corresponding to the hydrocarbon part of the organometallic molecule. 

Of the hydrocarbons toluene is the only one which nitrates sufficiently easily and yields a product which has the proper physical and explosive properties. Trinitrotoluene is the most widely used of the pure aromatic nitro compounds. It melts at such temperature that it can be loaded by pouring. It is easily and surely detonated, and is insensitive to shock, though not insensitive enough to penetrate armor-plate without exploding until afterwards. It is powerful and brisant, but less so than trinitrobenzene which would offer certain advantages if it could be procured in sufficient quantity. 

The ability to form addition compounds, especially with aromatic hydrocarbons composed of condensed rings, is one of the specific properties of aromatic poly-nitro compounds. For example, compounds of trinitrobenzene or picric acid with naphthalene, as well as with other hydrocarbons with condensed rings, are very characteristic. Generally they are intensely coloured. 

The presence of nitro groups enhances the acidic properties of the phenol group. This is why the trinitro derivatives are also called acids, e.g. trinitrophenol is known as picric acid and trinitroresorcinol as styphnic acid. These compounds readily form salts with metals or bases. Polynitro derivatives of phenols also form addition compounds with hydrocarbons, e.g. naphthalene. 

Constitution.—The composition of naphthalene is represented by the formula CioHg. What is its constitution In the first place it is a hydrocarbon similar in its chemical properties to benzene and not to methane. It readily forms nitro and sulphonic acid derivatives and its hydroxyl derivatives are analogom to phenols, not to alcohols. It also yields hydrogen and halogen addition products like benzene. The true constitution of the compound has been established by reactions both of decomposition and of synthesis. 

The compounds produced when the acid properties of the hydroxyl group are removed by introduction of an alcohol radical are colourless, for instance, nitroanisol behaves like a nitro-derivative of a hydrocarbon. 

Atoms of other elements, typically oxygen, nitrogen and sulphur, are incorporated into the basic hydrocarbon structures, usually as peripheral components known as functional groups (Table 2.1). Each functional group confers specific properties on the compound, and can be a major factor in determining the chemical behaviour of the compound. Functional groups include the hydroxyl (-OH), carboxyl (-COOH), amino (-NH2) and nitro groups (-N02). The -OH and... 

It is believed, that the suspected carcinogenic properties of the particulate matter is related to some kind of polynuclear aromatic hydrocarbon (PAH), adsorbed on the carbon nucleus nitro PAH and the carboxy PAH have been mentioned in this respect. 

Nitro Compounds as Explosives.—Nitro compounds prepared from aromatic hydrocarbons and certain of their derivatives were very important explosives used in the recent war. The compounds differ markedly in the properties which are characteristic of explosives namely, (1) sensitiveness to shock, (2) explosive force, and (3) the velocity of the explosion through the substance. If (1) is very high the explosive can not be transported very safely (2) determines the amount of the explosive to be used if (3) is very high the pressure is developed to its maximum so suddenly that rupture of the gun in which it is used may take place. Substances which are very sensitive to shock are used as detonators or boosters a small amount of the material is exploded by the trigger and the explosive wave set up causes the explosion of the less sensitive material. Mercury fulminate, lead azide, Pb(Ns)2, and several nitro derivatives of aniline (see below) are used for this purpose. 

Classification Aliphatic nitro compd. nitroparaffin Empirical C3H7NO2 Formula CH3CH(N02)CH3 Properties Colorless to very It. yel. clear oily liq. mild fruity odor sol. in most aromatic hydrocarbons, alcohols, esters, ketones, chloroform, ethers, lower carboxylic acids si. sol. in water m.w. 89.09 sp.gr. 0.992 (20/20 C) vapor... 

The nitroalkanes are named as derivatives of the hydrocarbon with the prefix nitro. The primary or secondary position of the nitro group on propane is indicated by the number 1 or 2. The structure of nitromethane is CH3NO2, CH3CH2NO2 is nitroethane, CH3CH2CH2NO2 is 1-nitropropane, and CH3-CH(N02)CH3 is 2-nitropropane. The CA index names (Chemical Abstract Index, American Chemical Society) for each nitroalkane is listed in Table 17.1 along with the solvent s physical properties. The CAS numbers refer to the major nitroalkane component. Refer to the Material Safety Data Sheet (MSDS) for CAS numbers of any minor impurities in the solvent. 

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