2. Infrared irradiation, actual use around the world

Considering the use of infrared irradiation, as an activating mode of reaction in complement to its employment to activate the extraction of secondary metabolites, in this chapter after a profound literature search, the obtained information was organized and presented in several sections. Each one of these sections was performed in order to highlight the actual status of the use of the infrared irradiation for the purposes previously commented. It is also important to note that the manuscript was created bearing in mind to attend the Decade to Educate in sustainable Development involving the green chemistry protocol.

Therefore, in the first place, the upgraded use of infrared irradiation around the world including both the early and the most recent studies in this field is showed.

#### 2.1 Knoevenagel condensation

In Table 1, three aldol type reactions are shown, employing MIR as the activating mode, using a natural bentonitic clay—Tonsil Actisil FF (TAFF) [9] as a catalyst. The target molecules were produced with good yields, short reaction times, in the absence of solvent, and involving easiest workup.

Infrared Irradiation, an Excellent, Alternative Green Energy Source DOI: http://dx.doi.org/10.5772/intechopen.83805

#### Table 1.

well recognized by the GC [7]. More recently, infrared irradiation (IR) has emerged as another excellent activating source into the green chemistry efforts [1, 7].

for the convenient promotion of organic transformations, this in addition to its employment to perform efficient natural product extractions, among others

this chapter: provide after a profound search in the literature, the actual status concerned to the employment of the infrared irradiation as an alternative mode to activate chemical reactions in addition to demonstrate its invaluable use to perform

It is worth noting that the NIR offers important advantages to carry out a reaction: due to its immediate response time, because it is efficiently used by convection, in addition to the longer life time of the tungsten-halogen filament

Considering the use of infrared irradiation, as an activating mode of reaction in complement to its employment to activate the extraction of secondary metabolites, in this chapter after a profound literature search, the obtained information was organized and presented in several sections. Each one of these sections was performed in order to highlight the actual status of the use of the infrared irradiation for the purposes previously commented. It is also important to note that the manuscript was created bearing in mind to attend the Decade to Educate in sus-

Therefore, in the first place, the upgraded use of infrared irradiation around the world including both the early and the most recent studies in this field is showed.

In Table 1, three aldol type reactions are shown, employing MIR as the activating mode, using a natural bentonitic clay—Tonsil Actisil FF (TAFF) [9] as a catalyst. The target molecules were produced with good yields, short reaction times, in

conveniently the extraction of interesting secondary metabolites.

far infrared with band spans from 4 to 1000 μm (FIR).

2. Infrared irradiation, actual use around the world

tainable Development involving the green chemistry protocol.

the absence of solvent, and involving easiest workup.

2.1 Knoevenagel condensation

process.

Figure 1.

Infrared irradiation zones.

Green Chemistry Applications

[1, 8].

36

The infrared irradiation has been already perceived by the scientific community

Regarding the last commentaries, it results appropriated to establish the goal of

On the other hand, taking as supportive reference the electromagnetic spectrum, the infrared region is divided into three zones, Figure 1. The shortwave or nearinfrared zone has band spans from 0.76 to 2 μm (NIR); the middle or medium infrared zone, with band spans from 2 to 4 μm (MIR); and the zone of long wave or

Knoevenagel condensation reactions.

#### 2.2 Nucleophilic additions

Several nucleophilic additions to various carbonylic substrates are confined in Table 2; consequently different products were obtained: heterocycles, Schiff bases, and the addition of a set of sulfur derivatives or the indolyl moiety to perezone, a natural product and its synthetic analog, Entry 10; it is important to note that the obtained indolyl molecules showed good activity against breast cancer cells.

In these processes, the MIR was employed to promote the reaction; in some cases, Co doped with ZnS nanoparticles or TAFF were used as catalyst. The reactions, in general, proceed with good to excellent yields. Also, a green procedure to obtain a set of five coumarins, was developed, comparing different activating modes, MW, NIR, US, MM, and mantle heating (MH), in the presence or absence of ethanol, Entry 9.

#### 2.3 Related macrocycles-benzyl oligomers

Various related macrocycles or benzyl oligomers were produced in the presence of TAFF as catalyst, in absence of solvent, considering a comparative study between MIR and MW, both processes show similar yields, Table 3.

#### 2.4 Multicomponent reaction

The multicomponent reaction implicates a very important and versatile strategy to generate an enormously number of reaction protocols to produce important molecules. In this sense, MIR and NIR have been usefully employed as activating reaction modes, to promote molecules related to the multicomponent protocols of

Biginelli, Hantzsch Meldrum, and Kamal-Qureshi (Table 4). The target molecules were in general with convenient green approach: without solvent or the use of EtOH as solvent, employing a green catalyst. The reported procedures involved short

E Reaction Ref. 10 [22]

Infrared Irradiation, an Excellent, Alternative Green Energy Source

DOI: http://dx.doi.org/10.5772/intechopen.83805

E Reaction Ref. 1 [23]

2 [23]

Important practices, within organic chemistry, are the reduction-oxidation, procedures. Thus, into the green chemistry protocol, several attempts have been developed, particularly within photocatalysis field, for example Guo and coworkers present the photothermic reduction of graphene oxide employing MIR [38].

reaction times and easy workup.

Formation of related benzylic oligomers and macrocycles.

2.5 Redox procedures

E = Entry, Ref = Reference.

Table 3.

39

E = Entry, Ref = Reference.

Nucleophilic addition reaction.

Table 2.

E = Entry, Ref = Reference.

#### Table 2.

E Reaction Ref. 1 [13]

Green Chemistry Applications

2 [14]

3 [15]

4 [16]

5 [17]

6 [18, 19]

7 [20]

8 [20]

9 [21]

38

Nucleophilic addition reaction.
