# Cleaner Processes for Making Laundry Soap from Vegetable Oils and an Essential Oil
## 1 Introduction
This is chosen not only for the smell but also for the additional effects it offers to the soap. Essential oils are extracted from plants such as _Azadirachta indica A. Juss_ (Neem), _Melaleuca alternifolia_ (Tea Tree) and _Thymus vulgaris_ L. (Thyme). The Neem essential oil can be used because it has multiple effects: anti-irritant, antimicrobial, antiseptic, insect repellent, purifying, and antifungal [43; 44; 45; 46]. The composition of _Neem essential oil_ depends on the raw material used in the extraction process (seeds, leaves or fresh flowers) of the _Azadirachta indica A_. Juss plant. Other factors are related to the geographical area in which the plant is grown, namely, the climate and nutrients in the soil. Thus, Neem essential oil extracted from the seeds of the plant cultivated in Iran has as main components several fatty acids (about 53.5%) (such as hexadecanoic acid (34.0%), oleic acid (15.7%), methyl oleate (3.8%)) and aroma-activecompounds (5,6-dihydro-2,4,6-triethyl-(4H)-1,3,5-dithiazine (11.7%), and a sesquiterpene (eudesm-7(11)-en-4-ol (2.7%)) [47; 48]. Neem essential oil extracted from _fresh Neem flowers_ (from Iran) obtained by steam distillation contains sesquiterpenes, aromatic compounds, fatty acids, fatty acid esters, steroids, hydrocarbons 8-cadinene (9.43%) \(\alpha\)-copaene (7.03%), humulene (3.7%), \(\delta\)-cubebene (3.04%), some sesquiterpenes, and unidentified organo-sulfur compounds [49; 50; 51]. Neem essential oil extracted from _Neem Leaves_ (from Iran) contains, in addition to the seeds or flowers, the compounds \(\gamma\)-elemene (20.8%), germacrene-B (20.3%), trans-caryophyllene (13.5%), hexadecanal (12.8%), and methyl linoleate (10.5%). Neem essential oil extracted from the leaves of the plant cultivated in India has the following components, identified by \({}^{1}\)HNMR analysis: azadiarchatin I, azadiarchatin A, deacetylnimbin, deacetylalannin, deacetyl nimbin, salanin, nimbin, quercetin-3-rutinoside, quercetin and kaempherd (as natural flavonoids) [52; 53]. Another study indicates that the essential oil extracted from Neem seeds collected in Senegal is mainly composed of non-terpene compounds with sulfur and nitrogen (about 80.2%) and few terpene compounds, mainly sesquiterpenes (about 7.5%) [54]. Neem essential oil, in smaller proportions, contains n-alkanes, aromatics esters, sulfur and nitrogen compounds and terpenoids [48; 49; 50; 51; 52; 53]. The volatile components of Neem essential oil are cis- and trans-3,5-diethyl-1,2,4-trithiolanes [49]. This variability in composition could influence the effectiveness of Neem essential oil in different applications, including soap formulation. The composition of Neem essential oil is particularly complex because it contains a large number of different phytochemicals, such as terpen (monoterpenes, sesquiterpenes, diterpenes, sesqu terpenes, and triterpenes) and terpenoids. The composition of terpen and terpenoids, their chemical structures, and the effects produced by them are presented in the literature [55]. Knowing the percentages of terpenoids in Neem essential oil is important because they influence the intensity of antibacterial and antifungal effects. So, according to the literature, the components responsible for the antimicrobial effects are diterpenoids (sugiol, nimbosone, nimbilicin, margosone and its derivatives), cyclicditerpenoids (margosolone, nimbinol, nimbionon, nimbisonol, nimbisodione, nimbosone, nimosone, methyl linbiol, methyl nimbionone, isoinbinolide, dimethyl nimbionol, sugiol), triterpenoids (nimocinol, Azadirachiemiaacetal), tetranort triterpenenoids (nimbidic acid, nimbidinin), tetracyclichtterpenoid (nimocinol), and sesquiterpenoids (\(\beta\)-farnesene) [56]. _Tea Tree essential oil_ extracted from _M. alternifolia_ leaves contains \(\alpha\)-pinene (21.64%), \(\varphi\)-terpinene (21.09%), terpinen-4-ol (17.31%), limonene (9.37%), and \(\alpha\)-cymene (6.54%).