Green Production of a High-Value Branched-Chain Diester: Optimization Based on Operating Conditions and Economic and Sustainability Criteria

Abstract

Branched-chain esters (BCEs) have found a large number of applications in cosmetics. Among them, neopentyl glycol dilaurate (NPGDL) stands out as an emollient, emulsifier, and skin-conditioning agent. This work presents the synthesis of NPGDL in a solvent-free medium using the two most common immobilized lipases: Novozym® 40086 (Rml) and Novozym® 435 (CalB). Results proved that the former biocatalyst has lower activity and certain temperature deactivation, although conversions ≥ 90% were obtained at 60 °C and 7.5% of catalyst. On the other hand, optimal reaction conditions for Novozym® 435 are 3.75% w/w of the immobilized derivative at 80 °C. Under optimal conditions, the process productivities were 0.105 and 0.169 kg NPGDL/L h, respectively. In order to select the best conditions for NPGDL production, studies on the reuse of the derivative and cost estimation have been performed. Economic study shows that biocatalytic processes can be competitive when lipases are reused for five cycles, yielding biocatalyst productivities of 56 and 122 kg NPGDL/kg biocatalyst using Novozym® 40086 and Novozym® 435, respectively. The final choice will be based on both economic and sustainability criteria. Green metric values using both biocatalysts are similar but the product obtained using Novozym® 40086 is 20% cheaper, making this alternative the best option.

Esters in the Food and Cosmetic Industries: An Overview of the Reactors Used in Their Biocatalytic Synthesis

“…To incorporate a greater number of studies, the search parameters were adjusted by removing the term “cosmetic”, resulting in 62 papers, of which 43 studies met the established criteria (tank reactors with a volume superior than 50 mL and cosmetic applications). Table 5 [ 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 ] compiles these papers. The esters synthesized fall into these categories: emollient esters [ 60 , 61 , 62 , 65 , 69 , 70 , 71 , ...…”

“…Table 5 [ 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 ] compiles these papers. The esters synthesized fall into these categories: emollient esters [ 60 , 61 , 62 , 65 , 69 , 70 , 71 , 73 , 74 , 79 , 80 ,…”

“…This guarantees a constant supply of enzymes. According to Table 5 , among 43 papers reviewed, 36 report the use of commercial lipases from different companies: Novozymes [ 60 , 61 , 62 , 63 , 64 , 65 , 66 , 68 , 70 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 82 , 88 , 90 , 91 , 92 , 93 , 96 , 97 , 98 , 99 , 101 ], Fermenta Biotech Ltd. (Thane, India) [ 71 , 81 , 83 , 84 , 86 , 89 , 95 ], and Purolite (King of Prussia, PA, USA) [ 80 ]. In five articles, researchers describe the use of an in-lab immobilized lipase [ 61 , 69 , 85 , 94 , 100 , 102 ], and only two studies involve microbial cells with lipase activity [ 67 , 87 ].…”

“…These methods involve the use of molecular sieves [ 64 , 67 , 71 , 75 , 81 ], vacuum operation with dry N 2 bubbling [ 66 , 69 , 70 , 72 , 73 , 80 , 85 , 91 , 93 , 97 , 100 ], and atmospheric evaporation [ 69 , 70 , 92 , 96 , 98 , 99 ]. Regarding the use of organic solvents as a reaction medium, solvent-free systems are becoming more prevalent [ 61 , 62 , 66 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 89 , 91 , 92 , 93 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 ]. This is probably ...…”

“…The high economic cost of such processes is perhaps the main drawback that opponents of biocatalytic synthesis cite as a reason not to pursue them as an alternative to traditional chemical routes. Therefore, economic studies have been conducted [ 85 , 93 , 98 , 99 ] demonstrating that the unit cost of these esters, when the immobilized lipase is appropriately reused, is comparable to that described in the literature for fine chemical compounds [ 103 ]. On the other hand, increasing environmental awareness is prompting manufacturers to implement sustainable processes that align with the principles of “Green Chemistry”.…”