An Experiment Attempting Synthesis Of Phenyl Sulfinyl Chloride Biology Essay

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In this report, the synthesis of phenyl sulfinyl chloride (PhS(O)Cl) was attempted via two different methods. The chloride was needed for the synthesis of perfluoroalkyl phenyl sulfoxide. The experimental approach is as followed:

Synthesis of Phenyl Sulfinyl Chloride PhS(O)Cl

Ph-SH + 2SO2Cl2 + CH3COOH àPhS(O)Cl + CH3COCl + 2SO2 + 2HCl

PhS(O)OH + SO2Cl2 à PhS(O)Cl + HCl +SO2

Synthesis of Perfluoroalkyl Phenyl Sulfoxide

RfI + C2F5MgX → RfMgX + C2F5I

RfMgX + PhS(O)Cl → PhS(O)Rf + ClMgX


Due to their unique properties and unusual reactivities, organofluorine compounds are of great importance.1Compounds containing a trifluoromethl group (CF3) are used in the field of materials, pharmaceuticals and agrochemistry.1 As such it is believed that the synthesis of Perfluoroalkyl Phenyl Sulfoxide will be very important to the Synthetic chemistry.

A Phosphinic acid is an organic derivative of hypophosphorous acid or derivatives of P- hydrocarbyl.2 It is the phosphorous oxo-acid or hydroxyl-phosphine oxide and is monobasic in character.3 A phosphinic acid is made when organic groups or phosphinates replace hydrogen atoms attached to phosphorous.3 These organophosphorous compounds, in particular phosphonates (RxP(O)(OR)3-x, x = 1, 2) are used worldwide in many applications, including industrial water treatment, household & industrial detergents, industrial cleaners and enhanced oil recovery operations.4 They also have biological applications as well as medicinal applications in that they are used to treat bone cancer and bone infections.5 Phosphinic acids are used as a starting material in the synthesis of Phenyl Sulfinyl Chloride.

Phenyl Sulfinyl Chloride can be synthesized using different methods. One such method includes first converting the appropriate sodium salt to the phosphinic acid then adding sulfuryl chloride to form the chloride. It can also be prepared by reacting thiophenol, sulfuryl chloride and acetic acid then subjecting it to vacuum distillation. However the thiophenol has a very unpleasant odour and the chloride tends to decompose quite easily. However these aren't the only methods of synthesis of the chloride. Some of the other methods taken from European Journal of Organic Chemistry 6 that provide significantly high yields are:

However there are limitations to using each method. For the first reaction, the thiophenol is very dangerous to work with since it is toxic by inhalation and absorption through the skin. For the second reaction, the thionyl chloride reacts with the grignard reagent and for the third reaction, Breathing high concentrations of oxygen (greater than 75 molar percent) causes symptoms of

hyperoxia which includes cramps, nausea, dizziness, hypothermia, amblyopia, respiratory

difficulties, bradycardia, fainting spells, and convulsions capable of leading to death.7

Phenyl Sulfinyl Chloride (PhS(O)Cl) is known to add to olefins with the formation of β-chlorosulfoxides. 8 It is used as a starting material to synthesize Perfluoroalkyl Phenyl Sulfoxide, PhS(O)Rf using the Grignard route, ie

RfI + C2F5MgX → RfMgX + C2F5I

RfMgX + PhS(O)Cl → PhS(O)Rf + ClMgX

Perfluoroalkyl compounds also known as fluorine-substituted organic compounds are important in Chemistry because they posses unique properties such as Chemical, Biological and thermal stability and this is due to the short C-F bond. They are quite useful since they too have medicinal purposes. They can also be used as pesticides or precursors for the manufacture of compounds which are biologically active.9 In addition, they are used in industrial stream processes and in commercial products.10 They have weak intermolecular forces and low surface energy.11 These characteristics are due to the fluorine atom having a high ionization potential as well as its extreme electronegativity and low polarisability. 11

Grignard reagents are prepared by adding the halogenoalkane to small portions of magnesium in a flask containing diethyl ether. The flask is fitted with a reflux condenser, and the mixture is warmed over a water bath for 20 - 30 minutes. 12Grignard reagents are extremely reactive and they are used to manufacture hydrocarbons, alcohols, carboxylic acids and numerous other compounds.12 Due to Grignard reagents being so reactive and unstable, they are prepared right before they are used, in a dry solvent under inert atmospheric conditions.12 These reagents participate in a wide variety of functionalisation reactions with electrophiles. Perfluoroalkyl Grignards are not as hazardous as perfluoroalkyl lithium reagents; however, both types of organometallics have similar reactivity. Bromide Grignard reagents are preferred over iodide Grignard reagents since using the iodide one gives off iodine which in turn reacts with the product.¹3

Phosphinic acids, Phenyl Sulfinyl Acids and Perfluoroalkyl Phenyl Sufoxide can be characterised using Nuclear Magnetic Resonance spectroscopy (NMR). NMR is used to analyse organic compounds and their structures. In this type of spectroscopy, there are two magnetic fields. The nuclei of atoms are placed in a magnetic field which is stationary and then exposed to another magnetic field which is moving. ¹4 The nuclei which undergoes this effect usually possess a property called spin which is a small magnetic field.¹4 Due to this, an NMR signal will be produced by the nucleus.¹4

Mass Spectrometry can also be used to characterize these compounds. A mass spectrometer is used to measure individual molecules. It does this by first ionizing the compound using a high energy beam of electrons and then separating and sorting the ions by focusing and accelerating the ions in a beam.¹5 This is done so that they will all possess the same kinetic energy. This beam is bent by an external magnetic field.¹5 The ions are then detected and the information is stored in a computer where it is analysed.¹5


To synthesize Phenyl Sulfinyl Chloride PhS(O)Cl and compare two different routes of synthesis:

PhSH (Thiophenol)

PhS(O)OH (Phenyl Sulfinic acid)

To use the PhS(O)Cl to synthesize Perfluoroalkyl Phenyl Sulfoxide (PhS(O)Rf) via Grignard