Synthesis of N,N-diethyldithiocarbamate nitrile ethyl and the chelating behaviors with metal ions

Article abstract of DOI:10.1155/2015/252967

The N,N-diethyldithiocarbamate nitrile ethyl (NND) was the nonionic polar collector, and it can synthesize the NND in dimethyl sulfoxide solvent. This method can effectively reduce the reaction intensity and the coefficient of the synthetic risk. The purity of NND which we synthesized is 94.23%, and the yield is 91.06%. UV analysis shows that the characteristic absorption peak wavelength of the NND is 276 nm, and its absorbance is 0.901. Based on the interaction of NND + Mⁿ⁺ (Mⁿ⁺ = Fe³⁺, Cu²⁺, Zn²⁺, Pb²⁺) and the quantum chemical calculation analysis of the NND and ethyl xanthate, we can conclude that the flotation performance of NND should be better than that of ethyl xanthate.

Full text of DOI:10.1155/2015/252967

Hindawi Publishing Corporation
Journal of Chemistry
Volume 2015, Article ID 252967, 6 pages
http://dx.doi.org/10.1155/2015/252967
Research Article
Synthesis of N,N-Diethyldithiocarbamate Nitrile
Ethyl and the Chelating Behaviors with Metal Ions
Zhonghui Zhang,1 Lijun Shi,2 Wen Deng,3 Dengbang Jiang,1 and Yaozhong Lan3
1e School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China
2Yunnan College of Business Management, Kunming 650106, China
3Yunnan University, Kunming 650091, China
Correspondence should be addressed to Zhonghui Zhang; 125514973@qq.com
Received 12 November 2014; Revised 25 December 2014; Accepted 23 January 2015
Academic Editor: Josefina Pons
Copyright © 2015 Zhonghui Zhang et al. is is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
e N,N-diethyldithiocarbamate nitrile ethyl (NND) was the nonionic polar collector, and it can synthesize the NND in dimethyl
sulfoxide solvent. is method can effectively reduce the reaction intensity and the coefficient of the synthetic risk. e purity of
NND which we synthesized is 94.23%, and the yield is 91.06%. UV analysis shows that the characteristic absorption peak wavelength
of the NND is 276 nm, and its absorbance is 0.901. Based on the interaction of NND + Mn+ (Mn+ = Fe3+, Cu2+, Zn2+, Pb2+) and the
quantum chemical calculation analysis of the NND and ethyl xanthate, we can conclude that the flotation performance of NND
should be better than that of ethyl xanthate.
1. Introduction
inhibitors. So it can achieve a better recovery for the objective
mineral, especially to the precious metals such as gold and
silver, thus reducing the pollution. erefore it has important
practical significance to research on the synthesis process of
the NND.
With the continuous development and utilization of mineral
resources, the mineral resources tend to be poor, fine, and
complex, and it becomes difficult to sort the multimetal
ore. is requires a higher concentration ratio. All of these
demonstrate the importance of flotation reagent and also
promote the great development of the scope of use, variety,
and quantity [1]. At present, many countries in the world are
researching more environmentally friendly flotation reagents
with low toxicity or newly nontoxic flotation reagents dosage
which has better performance and higher selectivity. ere
are many kinds of mineral processing reagents abroad with
more widespread use of efficient flotation reagent. It can
reduce the agent dosage because of high selectivity of the new
flotation reagents. Generally, less dosage of the reagent can
reduce the processing cost and the environment pollution [2].
e N,N-diethyldithiocarbamate nitrile ethyl (NND) is a
nonionic polar collector and has strongly collected properties
and good selectivity. Compared with the traditional xanthate
collectors, the consumption of this collector can be greatly
reduced, and it has foamed properties at the same time. Due
to the good selectivity, it can greatly reduce the dosage of
2. The Synthesis Process of the NND
ere are two steps of halogenated substitution method and
one step of unsaturated hydrocarbon additive method. One-
step method needs less equipment, shorter flow, and lower
cost. So this test adopts one step of unsaturated hydrocarbon
additive method to synthesize the NND. One of the starting
materials is the acrylonitrile (CH =CHC≡N) with a carbon-
2
carbon double bond and cyano-conjugate in the structure
of the acrylonitrile. e double bond is very active, and
it can participate in many kinds of additional reaction.
Another material is carbon bisulfide. e carbon atom with
a partial positive charge can generate complex formation by
reacting with many negative ions or unshared electron pair
compounds.

2
Journal of Chemistry
89
88
87
86
85
91
90
89
88
40
45
50
55
1:1.1
1.05 :1.15
1.1 :1.2
1.15 :1.2
Temperature (∘C)
Molar ratio of diethylamine to carbon disulfide
Figure 1: Effect of temperature on the synthesis.
Figure 2: e yield in different proportions of compounds.
Experiment was conducted in the aerator, and it was
Table 1: Infrared spectrum analysis of synthetic NND.
synthesized in a glass flask equipped with condensator. e
rotary evaporation method was used to remove part of the
outgrowth of acrylonitrile before synthesis. e flask was
placed in a constant temperature bath with the constant
magnetic stirring apparatus, and the materials took addi-
tional reaction in a phase. Afer the reaction was completed,
the product was processed by vacuum distillation in a
rotary evaporator to remove excess diethylamine and carbon
bisulfide to get the pure NND.
e absorption
Absorption peak
peak position/cm−1
Middle peaks
Middle peaks
Middle peaks
Strong peaks
Strong peaks
Strong peaks
C=S
R–Ar–N–Rꢀ
–C≡N
1205
1271
2248
2933
2978
3446
C–H
C–H
R–NH2
e reaction equation is as follows:
(CH CH ) NH + CS
3
2
2
2
(1)
S
Further test was done on reactive time in optimum
conditions of the temperature and reactant mass ratio. We
measured the amount of 10 mL of A and in accordance
with the mass ratio of 1.15 : 1.2 : 1 measured a quantity of
triethylamine, carbon bisulfide, and acrylonitrile. 50∘C was
kept, respectively, at different time to investigate the effects
of reactive time on the synthesis of NND. e test results are
shown in Figure 3.
Experiments show that the product yield almost has no
change or even some decline afer 90 minutes’ reaction, which
indicates that all NND has been fully synthesized afer 90
minutes. If heating at higher temperature was conducted
further, it could cause the decomposition or evaporate.
‖
A
+ CH CHCN ꢀꢁ ( CH CH ) N − CSCH CH CN
2
3
2
2
2
2
We measured the amount of 10.5 mL (0.1 mol) of tri-
ethylamine and in accordance with the mass ratio of 1 : 1 : 1
measured a quantity of carbon bisulfide and acrylonitrile,
slow mixing diethylamine, and carbon bisulfide in A phase
at less than 20∘C (A is a kind of important polar aprotic
solvents which is the mixture of the two methyl sulfoxides
and other sulfoxide organics. e mixture is not involved in
the synthesis reaction, and it can be distilled from the mixed
liquid composition and then isolated). en we slowed addi-
tion of acrylonitrile afer about 30 minutes. Afer exothermic
reactions, we kept 1.5 h, respectively, at different temperatures
to investigate effect of temperature on the synthesis of NND.
e test results are shown in Figure 1. We study the yield
in different proportions of compounds. e test results are
shown in Figure 2.
2.1. Infrared Spectral Analysis of NND. e NND which was
obtained under optimal conditions in the laboratory was
analyzed by infrared spectroscopy. e infrared spectrum test
of NND is shown in Figure 4, and the infrared spectrum
analysis is shown in Table 1.
Experiments show that it can get the maximum yield
of NND when mass ratio of diethylamine, carbon bisulfide,
and acrylonitrile is 1.15 : 1.2 : 1 and the optimum reaction
temperature is 50∘C because the diethylamine and carbon
bisulfide belong to the volatile material. Material loss is
more than normal temperature in the intense exothermic
reaction; thus, it is reasonable to increase the amount of
carbon bisulfide and triethylamine.
2.2. e Physical Properties of NND. NND is dark brown oily
liquid at room temperature. Its density is 1.08 g/mol, and there
is a faint smell of fish. It cannot be soluble in water but in
some organic solvents such as ethanol, ethyl ether, and carbon
tetrachloride. e melting point of NND is about 23∘C.

Journal of Chemistry
3
no change. is shows that NND + Pb2+ and NND + Zn2+
both have no interaction.
91.0
90.5
90.0
89.5
89.0
88.5
88.0
87.5
87.0
2.4. Quantum Chemical Calculations and the Flotation Per-
formance Interpretation of NND. Quantum chemical calcu-
lation of NND was calculated by Materials Studio sofware
which was developed by the Accelrys Company. At the
same time, we did quantum chemistry calculation of ethyl
xanthate which is a flotation reagent of the traditional sulfide
ore, and the calculation results were compared with the
NND to theoretically evaluate and interpret the flotation
performance.
e calculations are carried out by the DMol3 in Material
Studio which is a first-principle pseudopotential method
based on the density-functional theory (DFT). e exchange
correlation functional is the generalized gradient approxi-
mation (GGA) which is developed by Perdew, Burke, and
Ernzerhof (PBE). DFT calculations employing plane wave
(PW) basis sets and ultrasof pseudopotentials are performed.
e interactions between valence electrons and ionic core are
represented by ultrasof pseudopotentials. e kinetic energy
cut-off (310 eV) of the plane wave basis is used throughout the
study. For self-consistent electronic minimization, the Pulay
Density Mixing Method is employed with a convergence
tolerance of 2.0 × 10−6 eV/atom. e energy tolerance is
60
80
100
120
140
160
180
Reaction time (min)
Figure 3: Effect of reaction time on the synthesis.
90
80
70
60
50
40
30
20
10
Aliphatic nitrile
2.0 × 10−5 eV/atom, the force tolerance is 0.05 eV/A, and the
˚
R-Ar-N-Rꢀ
C-H
˚
displacement tolerance is 0.002 A.
2.4.1. e Quantum Calculation Analysis of Optimiza-
tion Molecular Structure of NND. e structure of NND
molecules was optimized, and the space structure is shown
in Figure 6(a). Due to the steric, N atoms connecting with
2 ethyl groups are not easy to interact with the ore. Each
atom Mulliken charge distribution of optimization molecular
structure of NND is shown in Table 2.
-C-S-
500
N-H
3000
3500
2500
2000
1500
)
1000
Wavenumber (cm−1
Figure 4: Infrared spectrum of synthetic NND.
As the metal ions in the ore are positive ions, the larger the
negative charges of Mulliken reagent molecules are, the more
likely they are to react with metal iron in ores. In Table 2, it is
obvious that S(12) (−0.524) is most likely to react with metal
iron in ores.
2.3. UV Spectral Analysis of Reaction of NND and
Some Metal Ions
2.3.1. UV Spectral Analysis of Reaction of NND. NND and
ethanol were mixed into the solution, and then the solution
is diluted that its molar concentration was 1 × 10−4 mol/L.
e ultraviolet absorption spectrum of the diluted dilution
is shown in Figure 5.
Based on the above analysis, we constructed the model of
NND + Cu2+, through the optimization calculation, and got
the effect of a stable model which is shown in Figure 6(b).
We can see that NND and metal ion together constitute
rectangular and hexagonal ring from Figure 6(b), so it has the
ability of collecting.
As can be seen from the graph, characteristic absorption
peak wavelength of NND is 276 nm, and its absorbance is
0.901.
Mulliken charge distribution of each atom of NND
interaction with copper ion is shown in Table 3.
By contrasting Table 3 with Table 2, we can see that S(5),
S(12), and N(9) have a strong interaction with copper ions,
and their Mulliken charge distributions have taken great
changes between before interaction with copper ions and
afer interaction with copper ions.
2.3.2. UV Spectral Analysis of Reaction of NND and NND +
Mn+. e ultraviolet spectrum of NND and NND + Mn+ is
shown in Figure 5.
e UV trend is consistent with Figures 5(a) and 5(b),
but the absorbance value of the maximum absorption peak
has to some extent decreased. is shows that the NND +
Fe3+ and NND + Cu2+ both have some interactions, and the
NND + Fe3+ takes the most obvious interaction; we also can
see that UV trend is consistent with Figures 5(c) and 5(d),
but absorbance value of the maximum absorption peak has
2.4.2. Quantum Chemical Calculation and the Calculation
Results of Ethyl Xanthate. Scholars put forward the hypoth-
esis of molecular adsorption and ion adsorption hypothesis
in a study of xanthate collection mechanism [3]. e former

4
Journal of Chemistry
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
230 240 250 260 270 280 290 300 310
Wavelength (nm)
230 240 250 260 270 280 290 300 310
Wavelength (nm)
Standard solution
Standard solution
Standard solution + Fe3+
Standard solution + Cu2+
(a)
(b)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
230 240 250 260 270 280 290 300 310
Wavelength (nm)
230 240 250 260 270 280 290 300 310
Wavelength (nm)
Standard solution
Standard solution
Standard solution + Zn2+
Standard solution + Pb2+
(c)
2+ (d)
Figure 5: Ultraviolet spectrum of NND and NND + Mn+ Mn+ = Fe3+, Cu , Zn2+, Pb2+
.
(a)
(b)
Figure 6: e molecular structure of NND and NND + Cu2+
.

Journal of Chemistry
5
(a)
(b)
(c)
Figure 7: e spatial structure of ethyl xanthate molecules combined with metal ions.
Table 2: Each atom Mulliken charge distribution of optimization molecular structure of NND.
Atomic categories
Electricity/ꢂ
C(1)
−0.322
C(10)
−0.321
H(19)
0.155
C(2)
−0.119
C(11)
N(3)
−0.243
S(12)
C(4)
0.412
H(13)
0.140
H(22)
0.123
S(5)
−0.212
H(14)
0.118
C(6)
−0.207
H(15)
0.109
C(7)
−0.301
H(16)
0.116
C(8)
0.111
H(17)
0.151
N(9)
−0.205
H(18)
0.170
Atomic categories
Electricity/ꢂ
−0.155
H(20)
0.191
−0.524
H(21)
0.168
Atomic categories
Electricity/ꢂ
H(23)
0.135
H(24)
0.121
H(25)
0.157
Table 3: Mulliken charge distribution of each atom of NND interaction with copper ion.
Atomic categories
Electricity/ꢂ
C(1)
−0.312
C(10)
−0.308
H(19)
0.140
C(2)
−0.139
C(11)
N(3)
−0.215
S(12)
C(4)
0.268
H(13)
0.133
H(22)
0.110
S(5)
−0.240
H(14)
0.113
C(6)
−0.214
H(15)
0.102
C(7)
−0.268
H(16)
0.106
C(8)
0.100
H(17)
0.140
H(26)
0.104
N(9)
−0.268
H(18)
0.124
Atomic categories
Electricity/ꢂ
−0.130
H(20)
0.128
−0.282
H(21)
0.141
Atomic categories
Electricity/ꢂ
H(23)
0.132
H(24)
0.105
H(25)
0.124
Cu(27)
0.206
Table 4: Mulliken charge distribution of ethyl xanthate molecules.
Atomic categories
C(1)
C(2)
O(3)
C(4)
0.385
S(5)
S(6)
H(7)
0.106
H(8)
0.125
H(9)
0.119
H(10)
0.109
H(11)
0.115
H(12)
0.125
Electricity/ꢂ
−0.309
−0.024
−0.307
−0.266
−0.279
Table 5: Mulliken charge distribution of optimization of ethyl xanthate anion.
Atomic categories
C(1)
C(2)
0.052
O(3)
C(4)
0.390
S(5)
S(6)
H(7)
H(8)
0.074
H(9)
0.012
H(10)
0.044
H(11)
Electricity/ꢂ
−0.242
−0.354
−0.518
−0.516
−0.023
−0.019
believes that xanthan molecule is effective form of xanthate in
the pulp, while the latter considers that it is xanthate anion. So
it is necessary to study the structure of two kinds of collectors.
e spatial structure diagram of optimizing ethyl xan-
thate molecules is shown in Figure 7(a), and the spatial
structure diagram of optimizing ethyl xanthate anion is
shown in Figure 7(b). It can be seen from the chart that two-
sulfur atom structure of ethyl xanthate anion is conjugate
structure.
with Mulliken charge distribution of optimization of ethyl
xanthate anion. As can be seen from the charts, Mulliken
charge distributions of S(5) and S(6) in molecule are −0.266
and −0.279, and Mulliken charge distributions of S(5) and
S(6) in ion are −0.518 and −0.516. It is obvious that the
flotation effect of xanthate ion will be good. is is consistent
with the actual. So we need to construct a better model.
en, we constructed the model of the ethyl xanthate ion
and the ethyl xanthate ion + Cu2+ through the optimization
calculation, and the stable model of the ethyl xanthate ion +
Cu2+ is shown in Figure 7(c). Mulliken charge distribution of
ethyl xanthate ion and the ethyl xanthate ion + Cu2+ is shown
in Table 6. It shows that two sulfurs interact with the Cu2+.
Mulliken charge distribution of ethyl xanthate molecules
is shown in Table 4. Mulliken charge distribution of optimiza-
tion of ethyl xanthate anion is shown in Table 5.
We determined the flotation characteristics by comparing
Mulliken charge distribution of ethyl xanthate molecules

6
Journal of Chemistry
Table 6: Mulliken charge distribution of ethyl xanthate ion and the ethyl xanthate ion + Cu2+.
Atomic categories
C(1)
C(2)
0.016
O(3)
C(4)
0.302
S(5)
S(6)
H(7)
0.009
H(8)
0.106
H(9)
0.047
H(10)
0.055
H(11)
0.004
Cu(12)
Electricity/ꢂ
−0.288
−0.351
−0.437
−0.416
−0.146
Table 7: Energy of NND and ethyl xanthate.
Energy
NND
NND + Cu2+
Ethyl xanthate ion
Ethyl xanthate ion + Cu2+
Binding energy
Total energy
−4.66059 Ha
−5.02687 Ha
−2.10020 Ha
−2.27400 Ha
−1212.84560 Ha
−2850.99734 Ha
−984.89550 Ha
−2622.85218 Ha
2.5. Energy of NND, Ethyl Xanthate, and the Reactants with
Copper Ions. e energy of NND, ethyl xanthate, and the
reactants with copper ions is shown in Table 7.
In the calculation process, we also calculated the binding
energy and the total energy of the optimization system. e
results are shown in Table 7.
References
[1] L. Bangrui, e Chelating Flotation Agent, Metallurgical Indus-
try Press, Beijing, China, 1992.
[2] Z. H. U. Jianguang, “Flotation reagent progress,” Metallic Ore
Dressing Abroad, vol. 3, pp. 14–17, 1998.
[3] Z. Guoxi, Physical Chemistry of Surface Active Agent, Peking
With the thermodynamic theory, the bigger energy
changes between the collector and Cu. e more easily the
collector reacts with copper ore, the better the performance
of the collector is.
University Press, Beijing, China, 1984.
e change value of combination energy of NND and Cu
ion is −0.36628 Ha. e change value of its total energy is
−1638.15174 Ha. e change value of combination energy of
ethyl xanthate and Cu ion is −0.17380 Ha. e change value
of its total energy is −1637.95668 Ha. e former change of
the binding energy and the total energy is larger than the
latter. erefore, in theory, the flotation performance of NND
should be better than that of ethyl xanthate.
3. Conclusion
(1) e purity of NND which we use UV-Visible Spec-
trophotometry to measure is 94.23%, and the yield is
91.06%.
(2) We know, according to the UV analysis, that the
characteristic absorption peak wavelength of NND
is 276 nm, and its absorbance is 0.901. NND + Fe3+
and NND + Cu2+ both have some interactions, and
NND + Fe3+ takes the most obvious interaction;
NND + Pb2+ and NND + Zn2+ both have no inter-
action.
(3) Based on quantum chemical calculation analysis of
NND and ethyl xanthate, the flotation performance
of NND should be better than that of ethyl xanthate.
Conflict of Interests
e authors declare that there is no conflict of interests
regarding the publication of this paper.
Acknowledgments
e project is supported by NSFC-YN (UI037603) and
Yunnan Provincial Science and Technology Department
(2009cc011).

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