2 ,3 -cyclic carbonate

Fig. 12.4. Vapor-to-water transfer data for saturated hydrocarbons as a function of accessible surface area, from [131]. Standard states are 1M ideal gas and solution phases. Linear alkanes (small dots) are labeled by the number of carbons. Cyclic compounds (large dots) are a = cyclooctane, b = cycloheptane, c = cyclopentane, d = cyclohexane, e = methylcyclopentane, f = methylcyclohexane, g = cA-l,2-dimethylcyclohexane. Branched compounds (circles) are h = isobutane, i = neopentane, j = isopentane, k = neohexane, 1 = isohexane, m = 3-methylpentane, n = 2,4-dimethylpentane, o = isooctane, p = 2,2,5-tri-metbylhexane. Adapted with permission from [74], Copyright 1994, American Chemical Society...

A similar process involving an all-carbon cyclic system has also been investigated [59]. Other examples involving the prototropic rearrangement of enediynes having an imino or a keto substituent at the propargylic position to form the corresponding enyne-allenes have also been observed [60, 61]. 

Fig. 15 Syntheses of heterocyclic and all carbon cyclic bent allenes...

Conformational isomerism in cyclohexane Cyclohexane (C6H12) is a six-carbon cyclic alkane that occurs extensively in nature. Many pharmaceutically important compounds possess cyclohexane rings, e.g. steroidal molecules. If we consider cyclohexane as a planar and regular hexagon, the angles are 120° (cf. 109.5° for sp hybrids). 

From a commercial standpoint, there is a large body of hydrocarbons that is very important and hence these are of relevance to first responders to a hazardous-materials incidents. These hydrocarbons are different in that they are not straight-chain hydrocarbons but have a structural formula that can only be called cyclical. The most common and most important hydrocarbon in this group is benzene. It is the first and simplest of the six-carbon cyclical hydrocarbons referred to as aromatic hydrocarbons. 

The same group highlighted the beneficial effect of adopting a membrane-divided cell with aqueous NaOH anolyte and non-aqueous (ACN) catholyte. The degradation of 1,2,3-TCB was performed on glassy carbon (cyclic voltammetry experiments) and Pd (preparative electrolyses) cathodes (Miyoshi et al. 2004b, c). 

Carbamate esters to protect alcohols, 62 to protect amines, 104, 387-388 to protect phenols, 167 Carbonate esters to protect alcohols, 104 to protect phenols, 165-167 Carbonates, cyclic, see Cyclic carbonate esters... 

The mild reaction conditions required allow the polymerization of chemically and thermally sensitive molecules. The highly versatile polymerizations can simultaneously polymerize lactones, hydroxyacids, cyclic carbonates, cyclic anhydrides,... 

It is now accepted that an efficient reaction requires the generation of a free radical or similar reactive species (5), in a position which permits transfer of the hydrogen atom through a cyclic transition state (6) comprising six atoms, four of which are carbon. Cyclic transition states with more or fewer atoms are apparently too strained to permit useful reaction. The reactive atom (X) may be 0 or N, and various methods have been devised for initiating the reaction in each case. If hydrogen transfer leads to a-CH2 radical (7), this may undergo reaction either with a suitable species from the solution, with another free radical, or with a reactive intramolecular site. 

Carbonic acid, cyclic propylene ester cyclic methylethylene carbonate cyclic propylene carbonate 4-methyl-2-oxo-l,3-dioxolane 1,2-propanediol cyclic carbonate 1,2-propylene carbonate. 

Again, it is easy to see that glucose might form a six-carbon cyclic unit. However this molecule cannot be considered aromatic because it lacks the double bonds found in the benzene ring. Compounds like glucose that contain elements other than carbon in the ring structure are called heterocyclic. 

Begin by writing the structure of cyclohexene. Recall that cyclohexene is a six-carbon cyclic alkene. Now add the water molecule to the equation. 

The sicric hindrance in prt>xiniity to the reactive hydroxy group represents again a limiting factor. It is noteworthy that whereas 1.2-diols gave the cyclic carbonates, cyclic products are not formed when the number of methylene groups between the alcohol functions increases. Thu.s, with 1.3- and 1,6-diols. the linear biscarbonaies become the sole reaction products. 

Palladium-carbon Cyclic hydroxylamines by reductive ring closure... 

Cyclic dimethylsiloxane tetramer. See Octamethyicyciotetrasiloxane Cyclic methylethylene carbonate. See Propylene carbonate Cyclic neopentanetetrayl bis (2,4-di-t-butylpheny ) ester phosphorous acid. See Bis (2,4-di-t-butylphenyi) pentaerythritoi diphosphite Cyclic neopentanetetrayl bis (octadecyl phosphite). See Distearyi penta-erythrityi diphosphite... 

Cyclic propylene carbonate Cyclic 1,2-propylene carbonate. See Propylene carbonate... 

CAS 108-32-7 EINECS/ELINCS 203-572-1 Synonyms Carbonic acid, cyclic propylene ester Carbonic acid, 1,2-propylene glycol ester 1,3-Carbon dioxypropane Cyclic methyleth-ylene carbonate Cyclic propylene carbonate Cyclic 1,2-propylene carbonate 1,3-Dioxolan-2-one, 4-methyl Dipropj ene carbonate 4-Methyl-1,3-dioxolan-2-one 1-Methyl ethylene carbonate 1,2-Propanediol carbonate 1,2-Propanediyl carbonate 1,2-Propylene carbonate Propylene glycol cyclic carbonate Classification Qrganic compd. carbonic acid ester Empirical C,HsQ,... 

Propylene carbonate CAS 108-32-7 EINECS/ELINCS 203-572-1 Synonyms Carbonic acid, cyclic propylene ester Carbonic acid, 1,2-propylene glycol ester 1,3-Carbonyl dioxypropane Cyclic methylethylene carbonate Cyclic propylene carbonate... 

---