Physical  Properties  of  liquids

 

Dr. Nagham  Mahmood  Aljamali

Organic Chemistry, Chemistry Department, College of  Education.

*Corresponding Author E-mail: dr.nagham_mj@yahoo.com

Characterization  of  liquids as  physical properties are the aim  of this  survey, types of liquids  like  (boiling m density,  other properties ) were  listed  in  tables

 

1. INTRODUCTION:

Mechanism of  any salvation depends  on  infinity  of  any  solvent  to  reactants :

·       Different solvents interact very differently with microwaves, because of their diverse polar and ionic properties of solvents.

·       Acetonitrile, DMF, and alcohols are often used solvents in microwave-assisted organic synthesis.

·       You might not need to change from the solvent that is specified for the reaction under traditional chemistry conditions. Firstly, try using the solvent that you would normally use.

·       Polar solvents (e.g. DMF, NMP, DMSO, methanol, ethanol, and acetic acid) couple well with microwaves due to their polarity, i.e. you can be sure that the temperature will rise substantially with these solvents.

·       Non-polar solvents (e.g. toluene, dioxane, THF) can be heated only if other components in the reaction mixture respond to microwave energy, i.e. if the reaction mixture contains either polar reactants or ions. When using less polar solvents, more concentrated reaction mixtures might be preferable. Under such circumstances, the achievable temperature can be quite high.

·       Ionic liquids are reported as new, environmentally friendly, recyclable alternatives to dipolar aprotic solvents for organic synthesis. The dielectric properties of ionic liquids make them highly suitable for use as solvents or additives in microwave-assisted organic synthesis. Ionic liquids consist entirely of ions and therefore absorb microwave irradiation extremely efficiently. Furthermore, they have a low vapour pressure, enhancing their suitability even further. Despite ionic liquids being salts, they dissolve to an appreciable extent in a wide range of organic solvents, and can therefore be used to increase the microwave absorption of low absorbing matrices.

·       Solvents can behave differently at elevated temperatures; most solvents have a lower dielectric constant and are hence less polar. Water is maybe the most interesting case. At elevated temperatures the bond angle in water widens and its dielectric properties approach those of organic solvents. Water at 250°C actually has similar dielectric properties as acetonitrile at room temperature. Thus, water can be used as a pseudo-organic solvent at elevated temperature where organic molecules will dissolve not only because of the temperature but also because of the change in dielectric properties. This makes some reactions that normally would not run in water perfectly feasible.

·       Solvents with low boiling points (e.g. methanol, dichloromethane and acetone), give lower achievable temperatures due to the pressure build-up in the vessel. If a higher absolute temperature is desirable to achieve a fast reaction it is advisable to change to a closely related solvent with a higher boiling point, e.g. dichloroethane instead of dichloromethane.

 

Polar  Solvents :

Have large dipole moments (aka “partial charges”); they contain bonds between atoms with very different electronegativities, such as oxygen and hydrogen.

 

Non polar   Solvents:  

Contain bonds between atoms with similar electronegativities, such as carbon and hydrogen (think hydrocarbons, such as gasoline).  Bonds between atoms with similar electronegativities will lack partial charges; it’s this absence of charge which makes these molecules “non-polar”.

 

There are two common ways of measuring this polarity. One is through measuring a constant called “dielectric constant” or permitivity. The greater the dielectric constant, the greater the polarity (water = high, gasoline = low).  A second comes from directly measuring the dipole moment.

 

There’s a final distinction to be made and this causes confusion. Some solvents are called “protic” and some are called “aprotic”.  What makes a solvent a “protic” solvent, anyway?

§  Protic solvents have O-H or N-H bonds. Why is this important? Because protic solvents can participate in hydrogen bonding, which is a powerful intermolecular force. Additionally, these O-H or N-H bonds can serve as a source of protons (H+).

§  Aprotic solvents may have hydrogens on them somewhere, but they lack O-H or N-H bonds, and therefore cannot hydrogen bond with themselves.

 

For the average first semester student, these distinctions come up the most in substitution reactions, where hydrogen bonding solvents tend to decrease the reactivity of nucleophiles; polar aprotic solvents, on the other hand, do not.

 

There are 3 types of solvents commonly encountered: nonpolar, polar aprotic, and polar protic. (There ain’t such a thing as a non-polar protic solvent).

OK, enough yammering. Here are some (hopefully useful) tables.

 

Nonpolar solvents: 

These solvents have low dielectric constants (<5) and are not good solvents for charged species such as anions. However diethyl ether (Et2O) is a common solvent for Grignard reactions; its lone pairs are Lewis basic and can help to solvate the Mg cation.

 

 

 

“Borderline” Polar aprotic solvents :

These solvents have moderately higher dielectric constants than the nonpolar solvents (between 5 and 20). Since they have intermediate polarity they are good “general purpose” solvents for a wide range of reactions. They are “aprotic” because they lack O-H or N-H bonds. For our purposes they don’t participate in reactions: they serve only as the medium.

 

 

Polar aprotic solvents

These solvents all have large dielectric constants (>20) and large dipole moments, but they do not participate in hydrogen bonding (no O-H or N-H bonds). Their high polarity allows them to dissolve charged species such as various anions used as nucleophiles (e.g. CN(-), HO(-), etc.). The lack of hydrogen bonding in the solvent means that these nucleophiles are relatively “free” in solution, making them more reactive. For our purposes these solvents do not participate in the reaction.

Polar protic solvents

Polar protic solvents tend to have high dielectric constants and high dipole moments. Furthermore, since they possess O-H or N-H bonds, they can also participate in hydrogen bonding. These solvents can also serve as acids (sources of protons) and weak nucleophiles (forming bonds with strong electrophiles).

They are most commonly used as the solvent for their conjugate bases. (e.g. H2O is used as the solvent for HO(-); EtOH is used as the solvent for EtO(-). )

 

 

These types of solvents are by far the most likely to participate in reactions.

 

Properties  Table of  Common  Solvents:

The solvents are grouped into non-polar, polar aprotic, and polar protic solvents and ordered by increasing polarity. The polarity is given as the dielectric constant. The properties  of solvents that exceed those of water are bolded.

 

Solvent	Chemical formula	Boiling point	Dielectric constant	Density	Dipole moment
Non- polar  solvents
Pentane	CH3-CH2-CH2-CH2-CH3	36 °C	1.84	0.626 g/ml	0.00 D
Cyclopentane	C5H10	40 °C	1.97	0.751 g/ml	0.00 D
Hexane	CH3-CH2-CH2-CH2-CH2-CH3	69 °C	1.88	0.655 g/ml	0.00 D
Cyclohexane	C6H12	81 °C	2.02	0.779 g/ml	0.00 D
Benzene	C6H6	80 °C	2.3	0.879 g/ml	0.00 D
Toluene	C6H5-CH3	111 °C	2.38	0.867 g/ml	0.36 D
1,4-Dioxane	/-CH2-CH2-O-CH2-CH2-O-\	101 °C	2.3	1.033 g/ml	0.45 D
Chloroform	CHCl3	61 °C	4.81	1.498 g/ml	1.04 D
Diethyl ether	CH3-CH2-O-CH2-CH3	35 °C	4.3	0.713 g/ml	1.15 D
Dichloromethane (DCM)	CH2Cl2	40 °C	9.1	1.3266 g/ml	1.60 D
Polar  aprotic  solvents
Tetrahydrofuran (THF)	/-CH2-CH2-O-CH2-CH2-\	66 °C	7.5	0.886 g/ml	1.75 D
Ethyl acetate	CH3-C(=O)-O-CH2-CH3	77 °C	6.02	0.894 g/ml	1.78 D
Acetone	CH3-C(=O)-CH3	56 °C	21	0.786 g/ml	2.88 D
Dimethylformamide (DMF)	H-C(=O)N(CH3)2	153 °C	38	0.944 g/ml	3.82 D
Acetonitrile (MeCN)	CH3-C≡N	82 °C	37.5	0.786 g/ml	3.92 D
Dimethyl sulfoxide (DMSO)	CH3-S(=O)-CH3	189 °C	46.7	1.092 g/ml	3.96 D
Nitromethane	CH3-NO2	100–103 °C	35.87	1.1371 g/ml	3.56 D
Propylene carbonate	C4H6O3	240 °C	64.0	1.205 g/ml	4.9 D
Polar  protic  solvents
Formic acid	H-C(=O)OH	101 °C	58	1.21 g/ml	1.41 D
n-Butanol	CH3-CH2-CH2-CH2-OH	118 °C	18	0.810 g/ml	1.63 D
Isopropanol (IPA)	CH3-CH(-OH)-CH3	82 °C	18	0.785 g/ml	1.66 D
n-Propanol	CH3-CH2-CH2-OH	97 °C	20	0.803 g/ml	1.68 D
Ethanol	CH3-CH2-OH	79 °C	24.55	0.789 g/ml	1.69 D
Methanol	CH3-OH	65 °C	33	0.791 g/ml	1.70 D
Acetic acid	CH3-C(=O)OH	118 °C	6.2	1.049 g/ml	1.74 D
Water	H-O-H	100 °C	80	1.000 g/ml	1.85 D

 

The following table shows that the intuitions from "non-polar", "polar aprotic" and "polar protic" are put numerically – the "polar" molecules have higher levels of δP and the protic solvents have higher levels of δH. Because numerical values are used, comparisons can be made rationally by comparing numbers. For example, acetonitrile is much more polar than acetone but exhibits slightly less hydrogen bonding.

Solvent	Chemical formula	δD Dispersion	δP Polar	δ H Hydrogen bonding
Non-polar solvents
Hexane	CH3-CH2-CH2-CH2-CH2-CH3	14.9	0.0	0.0
Benzene	C6H6	18.4	0.0	2.0
Toluene	C6H5-CH3	18.0	1.4	2.0
Diethyl ether	CH3CH2-O-CH2-CH3	14.5	2.9	4.6
Chloroform	CHCl3	17.8	3.1	5.7
1,4-Dioxane	/-CH2-CH2-O-CH2-CH2-O-\	17.5	1.8	9.0
Polar aprotic solvents
Ethyl acetate	CH3-C(=O)-O-CH2-CH3	15.8	5.3	7.2
Tetrahydrofuran (THF)	/-CH2-CH2-O-CH2-CH2-\	16.8	5.7	8.0
Dichloromethane	CH2Cl2	17.0	7.3	7.1
Acetone	CH3-C(=O)-CH3	15.5	10.4	7.0
Acetonitrile (MeCN)	CH3-C≡N	15.3	18.0	6.1
Dimethylformamide (DMF)	H-C(=O)N(CH3)2	17.4	13.7	11.3
Dimethyl sulfoxide (DMSO)	CH3-S(=O)-CH3	18.4	16.4	10.2
Polar protic solvents
Acetic acid	CH3-C(=O)OH	14.5	8.0	13.5
n-Butanol	CH3-CH2-CH2-CH2-OH	16.0	5.7	15.8
Isopropanol	CH3-CH(-OH)-CH3	15.8	6.1	16.4
n-Propanol	CH3-CH2-CH2-OH	16.0	6.8	17.4
Ethanol	CH3-CH2-OH	15.8	8.8	19.4
Methanol	CH3-OH	14.7	12.3	22.3
Formic acid	H-C(=O)OH	14.6	10.0	14.0
Water	H-O-H	15.5	16.0	42.3

Boiling  point:

Solvent	Boiling point (°C)[9]
Ethylene dichloride	83.48
Pyridine	115.25
Methyl isobutyl ketone	116.5
Methylene chloride	39.75
Isooctane	99.24
Carbon disulfide	46.3
Carbon tetrachloride	76.75
O-xylene	144.42

 

An important property of solvents is the boiling point. This also determines the speed of evaporation. Small amounts of low-boiling-point solvents like diethyl ether, dichloromethane, or acetone will evaporate in seconds at room temperature, while high-boiling-point solvents like water or dimethyl sulfoxide need higher temperatures, an air flow, or the application of vacuum for fast evaporation.

·       Low boilers: boiling point below 100 °C (boiling point of water)

·       Medium boilers: between 100 °C and 150 °C

·       High boilers: above 150 °C

 

Density  of  Solvents :

Most organic solvents have a lower density than water, which means they are lighter and will form a separate layer on top of water. An important exception: most of the halogenated solvents like  dichloromethane  or  chloroform will sink to the bottom of a container, leaving water as the top layer. This is important to remember when partitioning compounds between solvents and water in a separatory funnel during chemical syntheses.

 

Often, specific gravity is cited in place of density. Specific gravity is defined as the density of the solvent divided by the density of water at the same temperature. As such, specific gravity is a unitless value. It readily communicates whether a water-insoluble solvent will float (SG < 1.0) or sink (SG > 1.0) when mixed with water.

 

Solvent	Specific gravity
Pentane	0.626
Petroleum ether	0.656
Hexane	0.659
Heptane	0.684
Diethyl amine	0.707
Diethyl ether	0.713
Triethyl amine	0.728
Tert-butyl methyl ether	0.741
Cyclohexane	0.779
Tert-butyl alcohol	0.781
Isopropanol	0.785
Acetonitrile	0.786
Ethanol	0.789
Acetone	0.790
Methanol	0.791
Methyl isobutyl ketone	0.798
Isobutyl alcohol	0.802
1-Propanol	0.803
Methyl ethyl ketone	0.805
2-Butanol	0.808
Isoamyl alcohol	0.809
1-Butanol	0.810
Diethyl ketone	0.814
1-Octanol	0.826
p-Xylene	0.861
m-Xylene	0.864
Toluene	0.867
Dimethoxyethane	0.868
Benzene	0.879
Butyl acetate	0.882
1-Chlorobutane	0.886
Tetrahydrofuran	0.889
Ethyl acetate	0.895
o-Xylene	0.897
Hexamethylphosphorus triamide	0.898
2-Ethoxyethyl ether	0.909
N,N-Dimethylacetamide	0.937
Diethylene glycol dimethyl ether	0.943
N,N-Dimethylformamide	0.944
2-Methoxyethanol	0.965
Pyridine	0.982
Propanoic acid	0.993
Water	1.000
2-Methoxyethyl acetate	1.009
Benzonitrile	1.01
1-Methyl-2-pyrrolidinone	1.028
Hexamethylphosphoramide	1.03
1,4-Dioxane	1.033
Acetic acid	1.049
Acetic anhydride	1.08
Dimethyl sulfoxide	1.092
Chlorobenzene	1.1066
Deuterium oxide	1.107
Ethylene glycol	1.115
Diethylene glycol	1.118
Propylene carbonate	1.21
Formic acid	1.22
1,2-Dichloroethane	1.245
Glycerin	1.261
Carbon disulfide	1.263
1,2-Dichlorobenzene	1.306
Methylene chloride	1.325
Nitromethane	1.382
2,2,2-Trifluoroethanol	1.393
Chloroform	1.498
1,1,2-Trichlorotrifluoroethane	1.575
Carbon tetrachloride	1.594
Tetrachloroethylene	1.623

 

Molecular  Structure of  Solvents

Ability of a substance to dissolve another substance is determined by compatibility of their molecular structures (like dissolves like).

Types of  Molecular  Structures of  The  Solvents are as follows:

§  Polar protic solvents

A polar protic molecule consists of a polar group OH and a non-polar tail. The structure may be represented by a formula R-OH. Polar protic solvents dissolve other substances with polar protic molecular structure. Polar protic solvents are miscible with water (hydrophilic).
Examples of polar protic solvents: water (H-OH), acetic acid (CH₃CO-OH)methanol (CH₃-OH), ethanol (CH₃CH₂-OH), n-propanol (CH₃CH₂CH₂-OH), n-butanol (CH₃CH₂CH₂CH₂-OH).

 

§  Dipolar  aprotic  solvents

Dipolar aprotic molecules possess a large bond dipole moment (a measure of polarity of a molecule chemical bond). They do not contain OH group. 
Examples of dipolar aprotic solvents: acetone ( (CH₃)₂C=O ), ethyl acetate (CH₃CO₂CH₂CH₃), dimethyl sulfoxide ( (CH₃)₂SO ), acetonitrile (CH₃CN), dimethyl formamide ( (CH₃)₂NC(O)H ).

 

§  Non-polar solvents

Electric charge in the molecules of non-polar solvents is evenly distributed, therefore the molecules have low dielectric constant. Non-polar solvents are hydrophobic (immiscible with water). Non-polar solvents are liphophilic as they dissolve non-polar substances such as oils,fats, greases.
Examples of non-polar solvents: carbon tetrachloride (CCl₄), benzene (C6H6), and diethyl ether (CH₃CH₂OCH₂CH₃), hexane (CH₃(CH₂)4CH₃), methylene chloride (CH₂Cl₂).

 

 

 

Common Organic Solvents: Table of  Properties

Solvent	Formula	MW	Boiling  point  (°C)	Melting  point  (°C)	Density  (g/mL)	Solubility  in water  (g/100g)	Dielectric  Constant3,4	Flash  point  (oC)
acetic acid	C2H4O2	60.052	118	16.6	1.0446	Miscible	6.20	39
acetone	C3H6O	58.079	56.05	-94.7	0.7845	Miscible	21.01	-20
acetonitrile	C2H3N	41.052	81.65	-43.8	0.7857	Miscible	36.64	6
benzene	C6H6	78.11	80.1	5.5	0.8765	0.18	2.28	-11
1-butanol	C4H10O	74.12	117.7	-88.6	0.8095	6.3	17.8	37
2-butanol	C4H10O	74.12	99.5	-88.5	0.8063	15	17.26	24
2-butanone	C4H8O	72.11	79.6	-86.6	0.7999	25.6	18.6	-9
t-butyl alcohol	C4H10O	74.12	82.4	25.7	0.7887	Miscible	12.5	11
carbon tetrachloride	CCl4	153.82	76.8	-22.6	1.594	0.08	2.24	--
chlorobenzene	C6H5Cl	112.56	131.7	-45.3	1.1058	0.05	5.69	28
chloroform	CHCl3	119.38	61.2	-63.4	1.4788	0.795	4.81	--
cyclohexane	C6H12	84.16	80.7	6.6	0.7739	<0.1	2.02	-20
1,2-dichloroethane	C2H4Cl2	98.96	83.5	-35.7	1.245	0.861	10.42	13
diethylene glycol	C4H10O3	106.12	246	-10	1.1197	10	31.8	124
diethyl ether	C4H10O	74.12	34.5	-116.2	0.713	7.5	4.267	-45
diglyme (diethylene glycol  dimethyl ether)	C6H14O3	134.17	162	-68	0.943	Miscible	7.23	67
1,2-dimethoxy- ethane (glyme, DME)	C4H10O2	90.12	84.5	-69.2	0.8637	Miscible	7.3	-2
dimethyl-  formamide (DMF)	C3H7NO	73.09	153	-60.48	0.9445	Miscible	38.25	58
dimethyl sulfoxide (DMSO)	C2H6OS	78.13	189	18.4	1.092	25.3	47	95
1,4-dioxane	C4H8O2	88.11	101.1	11.8	1.033	Miscible	2.21(25)	12
ethanol	C2H6O	46.07	78.5	-114.1	0.789	Miscible	24.6	13
ethyl acetate	C4H8O2	88.11	77	-83.6	0.895	8.7	6(25)	-4
ethylene glycol	C2H6O2	62.07	195	-13	1.115	Miscible	37.7	111
glycerin	C3H8O3	92.09	290	17.8	1.261	Miscible	42.5	160
heptane	C7H16	100.20	98	-90.6	0.684	0.01	1.92	-4
Hexamethylphosphoramide  (HMPA)	C6H18N3OP	179.20	232.5	7.2	1.03	Miscible	31.3	105
Hexamethylphosphorous  triamide (HMPT)	C6H18N3P	163.20	150	-44	0.898	Miscible	??	26
hexane	C6H14	86.18	69	-95	0.659	0.014	1.89	-22
methanol	CH4O	32.04	64.6	-98	0.791	Miscible	32.6(25)	12
methyl t-butyl ether (MTBE)	C5H12O	88.15	55.2	-109	0.741	5.1	??	-28
methylene chloride	CH2Cl2	84.93	39.8	-96.7	1.326	1.32	9.08	1.6
N-methyl-2-pyrrolidinone (NMP)	CH5H9NO	99.13	202	-24	1.033	10	32	91
nitromethane	CH3NO2	61.04	101.2	-29	1.382	9.50	35.9	35
pentane	C5H12	72.15	36.1	-129.7	0.626	0.04	1.84	-49
Petroleum ether (ligroine)	--	--	30-60	-40	0.656	--	--	-30
1-propanol	C3H8O	88.15	97	-126	0.803	Miscible	20.1(25)	15
2-propanol	C3H8O	88.15	82.4	-88.5	0.785	Miscible	18.3(25)	12
pyridine	C5H5N	79.10	115.2	-41.6	0.982	Miscible	12.3(25)	17
tetrahydrofuran (THF)	C4H8O	72.106	65	-108.4	0.8833	30	7.52	-14
toluene	C7H8	92.14	110.6	-93	0.867	0.05	2.38(25)	4
triethyl amine	C6H15N	101.19	88.9	-114.7	0.728	0.02	2.4	-11
water	H2O	18.02	100.00	0.00	0.998	--	78.54	--
water, heavy	D2O	20.03	101.3	4	1.107	Miscible	??	--
o-xylene	C8H10	106.17	144	-25.2	0.897	Insoluble	2.57	32
m-xylene	C8H10	106.17	139.1	-47.8	0.868	Insoluble	2.37	27
p-xylene	C8H10	106.17	138.4	13.3	0.861	Insoluble	2.27	27

 

 

Choosing  Solvent  for  Recrystallization:

The most common method of purifying solid organic compounds is by recrystallization. In this technique, an impure solid compound is dissolved in a solvent and then allowed to slowly crystallize out as the solution cools. As the compound crystallizes from the solution, the molecules of the other compounds dissolved in solution are excluded from the growing crystal lattice, giving a pure solid.

 

Crystallization of a solid is not the same as precipitation of a solid. In crystallization, there is a slow, selective formation of the crystal framework resulting in a pure compound. In precipitation, there is a rapid formation of a solid from a solution that usually produces an amorphous solid containing many trapped impurities within the solid's crystal framework. For this reason, experimental procedures that produce a solid product by precipitation always include a final recrystallization step to give the pure compound.

 

The process of recrystallization relies on the property that for most compounds, as the temperature of a solvent increases, the solubility of the compound in that solvent also increases. For example, much more table sugar can be dissolved in very hot water (just below the boiling point) than in water at room temperature. What will happen if a concentrated solution of hot water and sugar is allowed to cool to room temperature? As the temperature of the solution decreases, the solubility of the sugar in the water also decreases, and the sugar molecules will begin to crystallize out of the solution. (This is how rock candy is made.) This is the basic process that goes on in the recrystallization of a solid.

 

The steps in the recrystallization of a compound are:

1.     Find a suitable solvent for the recrystallization;

2.     Dissolve the impure solid in a minimum volume of hot solvent;

3.     Remove any insoluble impurities by filtration;

4.     Slowly cool the hot solution to crystallize the desired compound from the solution;

5.     Filter the solution to isolate the purified solid compound.

 

Choosing  a solvent :

The first consideration in purifying a solid by recrystallization is to find a suitable solvent. There are four important properties that you should look for in a good solvent for recrystallization.

 

1.     The compound should be very soluble at the boiling point of the solvent and only sparingly soluble in the solvent at room temperature. This difference in solubility at hot versus cold temperatures is essential for the recrystallization process. If the compound is insoluble in the chosen solvent at high temperatures, then it will not dissolve. If the compound is very soluble in the solvent at room temperature, then getting the compound to crystallize in pure form from solution is difficult. For example, water is an excellent solvent for the recrystallization of benzoic acid. At 10°C only 2.1 g of benzoic acid dissolves in 1 liter of water, while at 95 °C the solubility is 68 g/L.

2.     The unwanted impurities should be either very soluble in the solvent at room temperature or insoluble in the hot solvent. This way, after the impure solid is dissolved in the hot solvent, any undissolved impurities can be removed by filtration. After the solution cools and the desired compound crystallizes out, any remaining soluble impurities will remain dissolved in the solvent.

3.     The solvent should not react with the compound being purified. The desired compound may be lost during recrystallization if the solvent reacts with the compound.

4.     The solvent should be volatile enough to be easily removed from the solvent after the compound has crystallized. This allows for easy and rapid drying of the solid compound after it has been isolated from the solution.

 

Finding a solvent with the desired properties is a search done by trial and error. First, test the solubility of tiny samples of the compound in test tubes with a variety of different solvents (water, ethanol, methanol, ethyl acetate, diethyl ether, hexane, toluene, etc.) at room temperature. If the compound dissolves in the solvent at room temperature, then that solvent is unsuitable for recrystallization. If the compound is insoluble in the solvent at room temperature, then the mixture is heated to the solvent's boiling point to determine if the solid will dissolve at high temperature, and then cooled to see whether it crystallizes from the solution at room temperature.

 

REFERENCES :

1- Miller, B.Ê Advanced Organic Chemistry: Ê Reactions and Mechanisms. Ê Prentice  Hall: Ê Upper Saddle River, NJ, 1998.

2-   P. Sykes ; "A guide Book to Mechanism in Organic Chemistry'' , 5^th Ed ., Longman, (1974) .

3-   R . E . Brewster , W. E. McEwen ; ''Organic Chemistry" , Ch . 30^ed Ed ., p.638 , (1971) .

4-- B.A. Marry ; "Organic Reaction Mechanism" , Ch . 1, Jon Willey      sons , (2005) . 

5-   L.F. Fieser and K.L. Eilliamson , ''Organic Experiment" 5^th Ed ., DC . Heath and company Toronto , Canada , p. 270 . (1983) .

6-   F. A. Carey and R. J. Sund berg "Advanced Organic Chemistry" part A:strures and Mechanisms, 2^nded ., Plenum Press. New York, p. 243, (1983).

7-   Nagham  M  Aljamali ., As. J. Rech.,  2014 , 7 ,9 , 810-838.

8-   C.O. Wilson and O. Givold, "Text book of Organic Medicinal and pharmaceutical Chemistry", 5^th Ed ., Pitman Medical Publishing Co. LTD, London copy right. C by. J. B. Lippin Cott Company (1966) .

 9- Nagham  M  Aljamali.,  Int. J. Curr. Res. Chem. Pharma. Sci. 1(9):(2014):121–151.

10- Nagham  M  Aljamali.,  Int. J. Curr. Res. Chem. Pharma. Sci. 1(9): (2014):88- 120.

 

 

 

 

Received on 05.08.2016         Modified on 20.08.2016

Accepted on 19.09.2016         © AJRC All right reserved