Names | |
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Preferred IUPAC name Bis(2-methylpropyl) benzene-1,2-dicarboxylate | |
Other names Diisobutyl phthalate Di-iso-butyl phthalate Di(i-butyl)phthalate Diisobutyl ester of phthalic acid 1,2-benzenedicarboxylic acid Bis(2-methylpropyl)ester Di(isobutyl) 1,2-benzenedicarboxylate Isobutyl-O-phthalate DIBP DiBP Palatinol IC | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.001.412 |
EC Number |
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KEGG | |
PubChem CID | |
RTECS number |
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UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C16H22O4 | |
Molar mass | 278.348 g·mol−1 |
Appearance | Colorless viscous liquid |
Density | 1.038 g/cm3 |
Melting point | −37 °C (−35 °F; 236 K) |
Boiling point | 320 °C (608 °F; 593 K) |
1 mg/L at 20 °C | |
log P | 4.11 |
Vapor pressure | 0.01 Pa at 20 °C |
Hazards | |
GHS labelling: | |
Danger | |
H360Df | |
P201, P202, P281, P308+P313, P405, P501 | |
NFPA 704 (fire diamond) | |
Flash point | 185 °C (365 °F; 458 K) c.c. |
400 °C (752 °F; 673 K) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Diisobutyl phthalate (DIBP) is a phthalate ester having the structural formula C6H4(COOCH2CH(CH3)2)2. It is formed by the esterification of isobutanol and phthalic anhydride. This and other phthalates are used as plasticizers due to their flexibility and durability. They are found in many industrial and personal products, such as lacquers, nail polish and cosmetics. [1] DIBP can be absorbed via oral ingestion and dermal exposure. [2] When it comes to excretion, DIBP is first converted into the hydrolytic monoester monoisobutyl phthalate (MIBP). The primary excretory route is urine, with biliary excretion being noted in minor amounts. DIBP has lower density and freezing point than the related compound dibutyl phthalate (DBP). [2]
It is used as a plasticizer additive in a range of plastic and rubber materials. [2] It has low volatility, which makes it ideal for use in products that require long-lasting flexibility, e.g. automotive parts, wire and cable insulation, and flooring. [3] It is dense and water-insoluble. [4]
DIBP has been found to be relatively non-toxic, but high levels of exposure to the compound may cause irritation to the eyes, skin and respiratory tract. [2] However, in recent years, concerns have been raised about the potential health risks of exposure to phthalates, including DIBP. Therefore, several countries have restricted or even banned the use of certain phthalates in products. [3] DIBP has been detected in various environmental matrices, such as air, water, and sediment. DIBP is known to bioaccumulate in certain aquatic species [5]
DIBP is synthesized by reaction of phthalic anhydride with isobutanol. Various acids are used as a catalyst, such as sulfuric acid, sulfonated graphene, or iron(III) chloride. Water is a byproduct.
Using sulfuric acid, the yield is 61% yield. [6]
Sulfonated graphene is a heterogeneous catalyst that has several advantages over traditional liquid acids like sulfuric acid. [7] Sulfonated graphene can be easily separated from the reaction mixture by filtration and can be reused multiple times without reduction in activity. [8] Furthermore, sulfonated graphene is environmentally friendly, as it does not produce hazardous waste materials that are typically generated during the use of traditional liquid acid catalysts. This method has a 95% yield. [7]
Lewis acids, such as FeCl3, can also be used as the catalyst. [9] The Lewis acid catalysis process can be run at lower temperatures (50-100 °C), and gives a yield of 86%. [9]
Diisobutyl phthalate is clear, colourless, oily liquid form with a mild odor. [10] It is insoluble in water but soluble in many organic solvents. [11]
DIBP can be sold as a pure substance or as a component of mixtures with other phthalate plasticizers or chemicals. Examples are dioctyl phthalate (DOP), diisononyl-phthalate (DINP), or bis(2-ethylhexyl) phthalate (DEHP). [12] It may be used as a component in formulations of several products including adhesives, paints, coatings and lubricants. [3] DIBP also may be present in consumer products such as toys, vinyl flooring, food packaging, and as a plasticizer or as a component of plastic formulations. [3] In many of these products DIBP is now prohibited to be used in formulations according to REACH. [12]
DIBP can undergo various reactions that may impact the environment. Examples include:
These reactions can impact the persistence, bioaccumulation, and toxicity in the environment and may have implications for human and ecosystem health.
The effects of DiBP exposure are mainly realized through its activation of peroxisome proliferator-activated receptor gamma (PPARγ). [19] PPARs are ligand-activated nuclear transcription factors, the family consists of PPARα, PPARβ/δ and PPARγ. [20] There are two isoforms of PPARγ, PPARγ2 is mainly present on cells in adipose tissue, whereas PPARγ1 is found on multiple cells like those in the gut, brain, blood vessels, and some immune and inflammatory cells. Transcriptional regulation through PPARs requires the formation of a heterodimer with retinoid X receptor (RXR). Upon activation by DiBP this PPARγ/RXR heterodimer binds to a DNA sequence called the PPAR response element (PPRE). [21] Binding of the transcription factor to this response element can result in either up- or down-regulation of genes. PPARγ is involved in lipid metabolism and storage as well as glucose metabolism through improving insulin sensitivity, [22] [23] so binding of DiBP leads to altered leptin and insulin levels. DiBP also leads to a down-regulation of proteins involved in steroid production, resulting in higher levels of androgenic hormones. [19]
Another type of pathway affected by DiBP exposure is the cytokine-cytokine receptor pathway. There are two pathways affected: the tumour necrosis factor receptor superfamily (TNFRSF) and the prolactin receptor pathway, both of which affect spermatogenesis. [19] In zebra fish, there are two types of TNFRSF: tnfrsf1a and tnfrsf1b, the latter of which is down-regulated by DiBP. Tnfrsf1b is involved in regeneration and tissue repair and its down-regulation has been shown to increase apoptosis of sperm cells. [24] Prolactin (PLR) on the other hand is up-regulated as a result of DiBP exposure. [19] Prolactin has many roles, including roles in cell regeneration and regulation of the male reproductive system. [25] High PLR concentrations as a result of phthalate exposure has been linked to reduced sperm concentrations in both adult men and zebra fish. [26] [19]
Upon entering circulation DiBP is quickly metabolized and excreted through urine, with metabolites reaching peak concentrations 2–4 hours after administration. [27] The main metabolite of DiBP is mono-isobutyl phthalate (MiBP), which makes up 70% of the excretion products. MiBP can be oxidized to either 2OH-mono-isobutyl phthalate (2OH-MiBP) or 3OH-mono-isobutyl phthalate (3OH-MiBP), which make up 20% and 1% of the excretion products respectively. These reactions are likely catalyzed by cytochrome P450 in the liver. [28] The ratio between MiBP and the oxidized metabolites changes depending on the amount of time that has passed since exposure. [27] The ratio between MiBP and 2OH-MiBP and that between MiBP and 3OH-MiBP show a similar trend. With the ratios being high, around 20-30:1, shortly after exposure and dropping gradually as more time passes to rest around 2-5:1. Therefore, a high ratio of oxidized metabolites to the monoester metabolite suggests that there was recent exposure to DiBP, within a few hours of measuring, while a lower ratio suggests that there has been more time since exposure. In addition to oxidation, MiBP can also undergo a glucuronidation reaction, resulting in the metabolite MiBP-glucuronide. [29]
There's insufficient data to determine if DIBP is associated with acute dermal or inhalation toxicity, eye or dermal irritation, or sensitization. There is evidence on DIBP being a subchronic toxicant. Exposure to the compound can induce changes in body weight, liver weight, reproductive effects, and developmental effects like testicular weight, spermatogenesis, fetal body weight, anogenital distance in male and female rats, and testicular testosterone production, among others. [30]
Biomonitoring studies show that exposures to DIBP have grown recently, presumably as a result of DIBPs use as a substitute for other phthalates such as dibutyl phthalate (DBP) in plastics. [31] [32] In the United States, for instance, the prevalence of MIBP detection in urine has risen from 72% of the general population in 2001–2002 to 96% in 2009–2010, according to data from the National Health and Nutrition Examination Survey (NHANES). [32]
The main issue with phthalate exposure is typically male reproductive toxicity, which is a risk that many phthalates share. [33]
A study conducted on rats shows that high dosage of DIBP administered by gavage to pregnant female rats between gestational days (GD) 6 and 20, exhibited signs of embryotoxicity and teratogenicity. [34] The growing male reproductive system was negatively impacted by DIBP, which is typical for phthalate esters. When phthalates are exposed in utero during the process of male sexual differentiation, a phenotype known as "phthalate syndrome" is created. This syndrome is characterized by underdevelopment of the male reproductive system, decreased anogenital distance (AGD), retention of the nipple in a female-like manner, and germ cell toxicity, among other things. [35] [36] [37] Therefore, these effects can be connected to decreased insulin-like-3 (INSL3) hormone, which controls transabdominal testicular descent, decreased androgen production in the testicles, which is essential for male sexual development, and disruption of seminiferous cord formation, Sertoli cells, and germ cell development via an unknown mode of action (MOA). [37] [38] [39]
Despite the limited studies in other species, research on zebrafish [40] shows that environmental exposure to DBP and DIBP can have serious consequences for fish offspring. As they go up the food chain and into polluted water, these phthalates can build up in aquatic organisms. Fish are susceptible to environmental toxins in their early lives, whether they are exposed to them directly or indirectly through their parents.
Species | Exposure Route | Dose | Effect | Reference |
Sprague-Dawley Rats | Oral (by gavage) | 250, 500, 750, and 1000 mg/kg/day | Pregnant females: Transient decrease in body weight gain, observed at 500 mg/kg and higher. Embryolethality and teratogenicity at 750 and 1000 mg/kg. Male fetuses: Undescended testis at 500 mg/kg. The degree of transabdominal migration of testis in relation to the bladder were disturbed at 500 mg/kg and above. | [34] |
Zebrafish | Chemical exposure | 10, 103 and 1038 μg L−1, (LC50) was 1037.7 μg L−1 | Parental individual DIBP exposure disturbed key genes in circadian rhythm and phototransduction signal pathways, which could influence the eye development of F1 larvae. | [40] |
Wistar Rats | Oral (by gavage) | 600 mg/kg | Disrupt fetal testicular development. AGD was reduced at GD 19 and GD 20/21 in males and increased in females exposed to DIBP. It also reduced bodyweights of male and female fetuses. | [41] |
Sprague-Dawley Rats | Oral (by gavage) | 100, 300, 600, and 900 mg/kg/day | Reduced maternal body weight gain from 73 g in controls to 48 and 43 g in the 600 and 900 mg/kg/day dose groups, respectively. | [42] |
Wistar Rats | Oral (by gavage) | 600 mg/kg bw/day | Reductions in fetal plasma leptin levels and in fetal insulin levels. Prenatal exposure disrupts fetal testosterone production in male rats by reducing the expression of several genes and proteins involved in steroidogenesis. In females, increases ovarian aromatase gene expression. DIBP also affected PPAR expression in the liver and testes. | [43] |
Sprague-Dawley Rats | Oral | 100, 300, 600, or 900 mg/kg/day | Significantly reduced T production. Reduced fetal AGD, T levels, and Insl3. | [44] |
Sprague-Dawley Rats | Oral (by gavage) | 125, 250, 500, 625 mg/kg/day | Doses ≥ 250 mg DIBP/(kg day) resulted in reduced AGD, and retained thoracic areolas/nipples at both early postnatal life, and adult necropsy. | [45] |
Cypermethrin (CP) is a synthetic pyrethroid used as an insecticide in large-scale commercial agricultural applications as well as in consumer products for domestic purposes. It behaves as a fast-acting neurotoxin in insects. It is easily degraded on soil and plants but can be effective for weeks when applied to indoor inert surfaces. It is a non-systemic and non-volatile insecticide that acts by contact and ingestion, used in agriculture and in pest control products. Exposure to sunlight, water and oxygen will accelerate its decomposition. Cypermethrin is highly toxic to fish, bees and aquatic insects, according to the National Pesticides Telecommunications Network (NPTN). It is found in many household ant and cockroach killers, including Raid, Ortho, Combat, ant chalk, and some products of Baygon in Southeast Asia.
Phthalates, or phthalate esters, are esters of phthalic acid. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used primarily to soften polyvinyl chloride (PVC). Note that while phthalates are usually plasticizers, not all plasticizers are phthalates. The two terms are specific and unique and cannot be used interchangeably.
A plasticizer is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture.
Endocrine disruptors, sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds are chemicals that can interfere with endocrine systems. These disruptions can cause numerous adverse human health outcomes, including alterations in sperm quality and fertility; abnormalities in sex organs‚ endometriosis‚ early puberty‚ altered nervous system or immune function; certain cancers; respiratory problems; metabolic issues; diabetes, obesity, or cardiovascular problems; growth, neurological and learning disabilities, and more. Found in many household and industrial products, endocrine disruptors "interfere with the synthesis, secretion, transport, binding, action, or elimination of natural hormones in the body that are responsible for development, behavior, fertility, and maintenance of homeostasis ."
Bisphenol A (BPA) is a chemical compound primarily used in the manufacturing of various plastics. It is a colourless solid which is soluble in most common organic solvents, but has very poor solubility in water. BPA is produced on an industrial scale by the condensation reaction of phenol and acetone. Global production in 2022 was estimated to be in the region of 10 million tonnes.
Xenoestrogens are a type of xenohormone that imitates estrogen. They can be either synthetic or natural chemical compounds. Synthetic xenoestrogens include some widely used industrial compounds, such as PCBs, BPA, and phthalates, which have estrogenic effects on a living organism even though they differ chemically from the estrogenic substances produced internally by the endocrine system of any organism. Natural xenoestrogens include phytoestrogens which are plant-derived xenoestrogens. Because the primary route of exposure to these compounds is by consumption of phytoestrogenic plants, they are sometimes called "dietary estrogens". Mycoestrogens, estrogenic substances from fungi, are another type of xenoestrogen that are also considered mycotoxins.
Bis(2-ethylhexyl) phthalate (di-2-ethylhexyl phthalate, diethylhexyl phthalate, diisooctyl phthalate, DEHP; incorrectly — dioctyl phthalate, DIOP) is an organic compound with the formula C6H4(CO2C8H17)2. DEHP is the most common member of the class of phthalates, which are used as plasticizers. It is the diester of phthalic acid and the branched-chain 2-ethylhexanol. This colorless viscous liquid is soluble in oil, but not in water.
Benzyl butyl phthalate (BBP) is an organic compound historically used a plasticizer, but which has now been largely phased out due to health concerns. It is a phthalate ester of containing benzyl alcohol, and n-butanol tail groups. Like most phthalates, BBP is non-volatile and remains liquid over a wide range of temperatures. It was mostly used as a plasticizer for PVC, but was also a common plasticizer for PVCA and PVB.
Dimethyl phthalate (DMP) is an organic compound and phthalate ester. it is a colourless and oily liquid that is soluble in organic solvents, but which is only poorly soluble in water.
Dibutyl phthalate (DBP) is an organic compound which is commonly used as a plasticizer because of its low toxicity and wide liquid range. With the chemical formula C6H4(CO2C4H9)2, it is a colorless oil, although impurities often render commercial samples yellow.
Cellulose acetate phthalate (CAP), also known as cellacefate (INN) and cellulosi acetas phthalas, is a commonly used polymer phthalate in the formulation of pharmaceuticals, such as the enteric coating of tablets or capsules and for controlled release formulations. It is a cellulose polymer where about half of the hydroxyls are esterified with acetyls, a quarter are esterified with one or two carboxyls of a phthalic acid, and the remainder are unchanged. It is a hygroscopic white to off-white free-flowing powder, granules, or flakes. It is tasteless and odorless, though may have a weak odor of acetic acid. Its main use in pharmaceutics is with enteric formulations. It can be used together with other coating agents, e.g. ethyl cellulose. Cellulose acetate phthalate is commonly plasticized with diethyl phthalate, a hydrophobic compound, or triethyl citrate, a hydrophilic compound; other compatible plasticizers are various phthalates, triacetin, dibutyl tartrate, glycerol, propylene glycol, tripropionin, triacetin citrate, acetylated monoglycerides, etc.
Triphenyl phosphate (TPhP) is the chemical compound with the formula OP(OC6H5)3. It is the simplest aromatic organophosphate. This colourless solid is the ester (triester) of phosphoric acid and phenol. It is used as a plasticizer and a fire retardant in a wide variety of settings and products.
Diisononyl phthalate (DINP) is a phthalate used as a plasticizer. DINP is typically a mixture of chemical compounds consisting of various isononyl esters of phthalic acid, and is commonly used in a large variety of plastic products.
1,2-Cyclohexane dicarboxylic acid diisononyl ester (DINCH) is a mixture of organic compounds with the formula C6H10(CO2C9H19)2. DINCH is colorless oil. It is used as a plasticizer for the manufacture of flexible plastic articles in sensitive application areas such as toys, medical devices, and food packaging. It is of interest as an alternative for phthalate plasticizers, which are implicated as endocrine disruptors.
Diethyl phthalate (DEP) is a phthalate ester. It occurs as a colourless liquid without significant odour but has a bitter, disagreeable taste. It is more dense than water and insoluble in water; hence, it sinks in water.
Bis(2-ethylhexyl) terephthalate commonly abbreviated DEHT (Dioctyl terephthalate or DOTP), is an organic compound with the formula C6H4(CO2C8H17)2. It is a non-phthalate plasticizer, being the diester of terephthalic acid and the branched-chain 2-ethylhexanol, which is often generically referred to as octyl. This colorless viscous liquid is used for softening PVC plastics and is known for chemical similarity to general purpose phthalates such as DEHP and DINP, but without any negative regulatory pressure. It possesses very good plasticizing properties and may be used as a direct replacement for DEHP and DINP in many applications.
Antiandrogens in the environment have become a topic of concern. Many industrial chemicals, including phthalates and pesticides, exhibit antiandrogen activity in animal experiments. Certain plant species have also been found to produce antiandrogens. In animal studies, environmental antiandrogens can harm reproductive organ development in fetuses exposed in utero as well as their offspring.
Monobutyl phthalate (MBP) is an organic compound with the condensed structural formula CH3(CH2)3OOCC6H4COOH. It is a white solid that features both an butyl ester group and a carboxylic acid group. It is the major metabolite of dibutyl phthalate. Like many phthalates, MBP has attracted attention as a potential endocrine disruptor.
Monobenzyl phthalate (MBzP) also known as 1,2-Benzenedicarboxylic acid, 1-(phenylmethyl) ester is an organic compound with the condensed structural formula C6H5CH2OOCC6H4COOH. It is the major metabolite of butyl benzyl phthalate(BBP), a common plasticizer. BBP can also be metabolized into monobutyl phthalate (MBP). Like many phthalates, BBP has attracted attention as a potential endocrine disruptor.
Gerald A. LeBlanc is an American biologist, toxicologist, author, and academic. He is a Professor Emeritus in the Department of Biological Sciences at the North Carolina State University.