94-26-8

Basic information

• Product Name: Butylparaben
• Synonyms: 4-hydroxy-benzoicacibutylester;4-Hydroxybenzoicaicdbutylester;Aseptoform Butyl;aseptoformbutyl;Benzoic acid, 4-hydroxy-, butyl ester;Benzoic acid, p-hydroxy-, butyl ester;Benzoicacid,4-hydroxy-,butylester;Butyl Butex
• CAS NO: 94-26-8
• Molecular Formula: C₁₁H₁₄O₃
• Molecular Weight: 194.23
• EINECS: 202-318-7
• Product Categories: Pharmaceutical Raw Materials;Aromatics;API
• Mol File: 94-26-8.mol

Chemical Properties

• Melting Point: 67-70 °C(lit.)
• Boiling Point: 156-157 °C3.5 mm Hg(lit.)
• Flash Point: 181℃
• Appearance: White to almost white/Crystalline Powder
• Density: 1.28
• Vapor Pressure: 0mmHg at 25°C
• Refractive Index: 1.5115 (estimate)
• Storage Temp.: 0-6°C
• Solubility: Soluble in DMSO, ethyl acetate, methanol.
• PKA: pKa 8.5 (Uncertain)
• Water Solubility: <0.1 g/100 mL at 17℃
• Stability: Stable. Combustible. Incompatible with strong oxidizing agents, strong alkalies.
• Merck: 14,1584
• BRN: 1103741
• CAS DataBase Reference: Butylparaben(CAS DataBase Reference)
• NIST Chemistry Reference: Butylparaben(94-26-8)
• EPA Substance Registry System: Butylparaben(94-26-8)

Safety Data

• Statements: 36/37/38
• Safety Statements: 22-24/25-37/39-26
• WGK Germany: 2
• RTECS: DH1980000
• TSCA: Yes
• Hazardous Substances Data: 94-26-8(Hazardous Substances Data)

Usage

Uses

Used in Pharmaceutical Industry:
Butylparaben is used as a preservative in pharmaceutical formulations for its antimicrobial properties, particularly against molds, yeasts, and to a lesser extent, bacteria. It helps maintain the stability and safety of medications by retarding microbial growth.
Used in Cosmetics Industry:
Butylparaben is used as a preservative in various cosmetics, including creams, lotions, ointments, and other skincare products. Its ability to inhibit the growth of molds, fungi, and yeasts contributes to the shelf life and safety of these products.
Used in Food Industry:
Butylparaben is used as a preservative in a wide range of food products such as salad dressings, mayonnaise, spiced sauces, mustard, frozen dairy products, and baked goods. It helps to prevent spoilage and maintain the quality of these foods by inhibiting the growth of undesirable microorganisms.
Used in Dental Care Products:
Butylparaben is used as a preservative in dentifrices, ensuring the stability and safety of these oral care products by preventing the growth of harmful microorganisms.
Used in Commercial Solutions:
Butylparaben is added to solutions like commercially prepared low-ionic strength saline (LISS) solutions and beer to retard microbial growth, thereby extending their shelf life and maintaining their quality. In comparison to other parabens, butylparaben is considered the best antifungal agent, making it a preferred choice for these applications.

Production method

Butylparaben is derived from the esterification between p-hydroxybenzoic acid and butanol. Butanol and p-hydroxybenzoic acid are heated together for being dissolved, slowly added dropwise of sulfuric acid, continue the refluxing for 8h. After cooling, add 4% sodium carbonate solution, separate the water layer, steam out the butanol, let it cool, filter to obtain the crude product, and then carry out ethanol recrystallization (solubility in ethanol: 200g/100ml).Take sulfuric acid as a catalyst; derive it from the reaction between p-hydroxybenzoic acid and butanol.

Toxicity

ADI is subject to postponed decision (FAO/WHO, 2001). LD50: 16.0 g/kg (mouse, subcutaneous injection). Mice subjecting to short-term toxicity test have gotten inhibited weight increase. There have been reports regarding to the acute dermatitis for human beings. In the p-hydroxybenzoic acid esters, this product gives the best anti-corrosion effect, but also the largest toxicity.

Content analysis

2g (accurate to 0.1mg) was taken and dried in silica gel for 5h before being transferred to the flask. Add 40 mL of 1mol/L of sodium hydroxide, flush flasks with water. Cover the surface of the dish and apply a small fire to boil 1h before cooling. Add 5 drops of bromothymol blue solution (TS-56), titrate the excess sodium hydroxide with 1 mol/L sulfuric acid, and make the color of the solution consistent with the buffer containing the same indicator (pH 6.5). Carry out a blank test at the same time and make the necessary calibration. 1ml/L sodium hydroxide per milliliter corresponds to the 194.2 mg of this product (C11H14O3).

Usage limit

Japan (1998, calculated on p-hydroxybenzoic acid; the data in parentheses is the amount converted into equivalent amount of this product, g/ kg), soy sauce 0.25 g/L (0.35 g/L), vinegar 0.1 g/L (0.14 g/L); Soft drinks and syrup: 0.1 (0.14); fruit sauce: 0.2 (0.28); fruits and vegetables 0.012 (0.016).

Hazards & Safety Information

Category :Toxic substances Toxic classification: poisoning Acute toxicity:? Oral-mouse LD50: 13200 mg/kg; celiac-mouse LD50: 230 mg/kg Stimulation Data:? Skin-Guinea Pig 5%/48 hours Mild Flammability and Hazardous characteristics:? Thermal decomposition; pungent irritation Smoke Storage and transportation characteristics:? Treasury: ventilated, low temperature and dry Fire extinguishing agent:? water, dry powder, foam, carbon dioxide

Preparation

Butyl paraben is prepared by esterifying p-hydroxybenzoic acid with butyl alcohol in the presence of an acid catalyst, such as sulfuric acid, and an excess of the specific alcohol.

Production Methods

Butylparaben is prepared by esterification of p-hydroxybenzoic acid with n-butanol.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

Butylparaben is incompatible with strong oxidizing agents and strong caustics.

Fire Hazard

Flash point data for Butylparaben are not available; however, Butylparaben is probably combustible.

Pharmaceutical Applications

Butylparaben is widely used as an antimicrobial preservative in cosmetics and pharmaceutical formulations. It may be used either alone or in combination with other paraben esters or with other antimicrobial agents. In cosmetics, it is the fourth most frequently used preservative. As a group, the parabens are effective over a wide pH range and have a broad spectrum of antimicrobial activity, although they are most effective against yeasts and molds. Owing to the poor solubility of the parabens, paraben salts, particularly the sodium salt, are frequently used in formulations. However, this may raise the pH of poorly buffered formulations. See Methylparaben for further information.

Safety

Butylparaben and other parabens are widely used as antimicrobial preservatives in cosmetics and oral and topical pharmaceutical formulations. Systemically, no adverse reactions to parabens have been reported, although they have been associated with hypersensitivity reactions generally appearing as contact dematitis. Immediate reactions with urticaria and bronchospasm have occurred rarely. See Methylparaben for further information. LD50 (mouse, IP): 0.23 g/kg LD50 (mouse, oral): 13.2 g/kg

storage

Aqueous butylparaben solutions at pH 3–6 can be sterilized by autoclaving, without decomposition. At pH 3–6, aqueous solutions are stable (less than 10% decomposition) for up to about 4 years at room temperature, while solutions at pH 8 or above are subject to rapid hydrolysis (10% or more after about 60 days at room temperature).

Incompatibilities

The antimicrobial activity of butylparaben is considerably reduced in the presence of nonionic surfactants as a result of micellization. Absorption of butylparaben by plastics has not been reported but appears probable given the behavior of other parabens. Some pigments, e.g. ultramarine blue and yellow iron oxide, absorb butylparaben and thus reduce its preservative properties. Butylparaben is discolored in the presence of iron and is subject to hydrolysis by weak alkalis and strong acids.

Regulatory Status

Butylparaben is regulated by the U.S. Environmental Protection Agency (EPA) under the Toxic Substances Control Act (TSCA) and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). In 1998 its pesticide registration status was listed as "cancelled" (U.S. EPA, 2003).Included in the FDA Inactive Ingredients Database (injections; oral capsules, solutions, suspensions, syrups and tablets; rectal, and topical preparations). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Nonmedicinal Ingredients.

InChI:InChI=1/C11H14O3/c1-2-3-4-8-7-9(12)5-6-10(8)11(13)14/h5-7,12H,2-4H2,1H3,(H,13,14)

Synthetic route

butan-1-ol (71-36-3) + 4-hydroxy-benzoic acid (99-96-7) → 4-hydroxybenzoic acid, butyl ester (94-26-8)

Conditions	Yield
With sulfuric acid In toluene Esterification; Heating;	99%
With [1-(3-sulfonic acid)]propyl-3-methylimidazolium hydrogen sulfate at 125 - 135℃; for 3h;	95.3%
With benzimidazole bisulfate ionic liquid Reflux;	95.3%

n-butyl 4-(methoxymethoxy)benzoate (251640-53-6) → 4-hydroxybenzoic acid, butyl ester (94-26-8)

Conditions	Yield
With carbon tetrabromide; triphenylphosphine In 1,2-dichloro-ethane at 40℃;	91%

methyl 4-hydroxylbenzoate (99-76-3) + butan-1-ol (71-36-3) → 4-hydroxybenzoic acid, butyl ester (94-26-8)

Conditions	Yield
With Zn4(OCOCF3)6O In di-isopropyl ether for 40h; Heating;	76%

di(methyl)tert-butyl(n-butoxy)silane (37170-50-6) + 4-hydroxy-benzaldehyde (123-08-0) → 4-hydroxybenzoic acid, butyl ester (94-26-8)

Conditions	Yield
With [4,4’-bis(1,1-dimethylethyl)-2,2’-bipyridine-N1,N1‘]bis [3,5-difluoro-2-[5-(trifluoromethyl)-2-pyridinyl-N]phenyl-C]iridium(III) hexafluorophosphate; Selectfluor In acetonitrile at 20℃; for 8h; Inert atmosphere; Irradiation;	73%

tetrachloromethane (56-23-5) + butan-1-ol (71-36-3) + phenol (108-95-2) → 4-hydroxybenzoic acid, butyl ester (94-26-8) + n-butyl salicylate (2052-14-4)

Conditions	Yield
With diiron nonacarbonyl at 130℃; for 6h; Inert atmosphere; Sealed tube;	A 62% B 38%

4-hydroxy-benzaldehyde (123-08-0) + butan-1-ol (71-36-3) → 4-hydroxybenzoic acid, butyl ester (94-26-8)

Conditions	Yield
Stage #1: 4-hydroxy-benzaldehyde; butan-1-ol With tris(pentafluorophenyl)borate for 0.25h; Green chemistry; Stage #2: With tert.-butylhydroperoxide In decane for 36h; Green chemistry;	61%

carbon dioxide (124-38-9) + tetra-n-butylammonium phenolate (16909-23-2) → 4-hydroxybenzoic acid, butyl ester (94-26-8) + 4-hydroxy-benzoic acid (99-96-7)

Conditions	Yield
With potassium carbonate at 125℃; under 37503 Torr; for 5h; Kolbe-Shmitt reaction;	A 10 % Chromat. B 35 % Chromat.

4-bromo-phenol (106-41-2) → 4-hydroxybenzoic acid, butyl ester (94-26-8)

Conditions	Yield
With CO; palladium-carbon

n-Butyl chloride (109-69-3) + 1-ethyl-3-methylimidazolium 4-hydroxybenzoate (1286216-54-3) → 4-hydroxybenzoic acid, butyl ester (94-26-8)

Conditions	Yield
at 80℃; for 6h;	68.7 %Spectr.

p-hydroxybenzamide (619-57-8) + butan-1-ol (71-36-3) → 4-hydroxybenzoic acid, butyl ester (94-26-8)

Conditions	Yield
With zirconium-based metal-organic framework at 150℃; for 72h;	72 %Spectr.

4-hydroxybenzoic acid, butyl ester (94-26-8) + p-toluenesulfonyl chloride (98-59-9) → butyl 4-(tosyloxy)benzoate

Conditions	Yield
With dmap; triethylamine In dichloromethane for 2.25h; Inert atmosphere;	96%

4-hydroxybenzoic acid, butyl ester (94-26-8) → butyl 4-trimethylsiloxybenzoate

Conditions	Yield
With Hg; 1,1,1,3,3,3-hexamethyl-disilazane	94%

4-hydroxybenzoic acid, butyl ester (94-26-8) + chloromethyl methyl ether (107-30-2) → n-butyl 4-(methoxymethoxy)benzoate (251640-53-6)

Conditions	Yield
With sodium hydride In tetrahydrofuran at 20℃; for 12h; Etherification;	92%

4-hydroxybenzoic acid, butyl ester (94-26-8) + [1-(4-chlorobenzoyl)-5-methoxy-2-methylindol-3-yl]acetic acid (53-86-1) → 4{2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetoxy}benzoic acid butyl ester (1333343-65-9)

Conditions	Yield
With dmap; dicyclohexyl-carbodiimide In dichloromethane at 20℃; for 5h;	90.6%

4-hydroxybenzoic acid, butyl ester (94-26-8) + 1-Bromo-2-phenylacetylene (932-87-6) → C19H19BrO3

Conditions	Yield
With caesium carbonate In N,N-dimethyl-formamide at 110℃; for 12h; under air; sealed tube; stereoselective reaction;	88%

4-hydroxybenzoic acid, butyl ester (94-26-8) + 4,5-dichlorophthalonitrile (139152-08-2) → dibutyl 4,4’-[(1,2-phenylene)bis(oxy)dibenzoate]-2,3-dicarbonitrile

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 70℃; for 72h; Inert atmosphere;	88%

4-hydroxybenzoic acid, butyl ester (94-26-8) + 3-nitrobenzene-1,2-dicarbonitrile (51762-67-5) → 3-[4-(butoxycarbonyl)phenoxy]phthalonitrile

Conditions	Yield
With potassium carbonate In dimethyl sulfoxide at 20℃; Inert atmosphere;	87.2%

4-hydroxybenzoic acid, butyl ester (94-26-8) + C10H22Cl2N7P3 → C32H48N7O6P3

Conditions	Yield
With sodium hydride In tetrahydrofuran for 120h; Inert atmosphere; Cooling with ice; Reflux;	85%

4-hydroxybenzoic acid, butyl ester (94-26-8) + hex-5-ynoic acid (53293-00-8) → C17H20O4

Conditions	Yield
With 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride In dichloromethane at 25℃; for 72h;	77%

4-hydroxybenzoic acid, butyl ester (94-26-8) + 2-chloro-N-(1-oxo-1,3-dihydroisobenzofuran-5-yl)acetamide (612850-65-4) → butyl 4-(2-oxo-2-(1-oxo-1,3-dihydroisobenzofuran-5-ylamino)ethoxy)benzoate

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 25℃; for 16h; Inert atmosphere;	71%

4-hydroxybenzoic acid, butyl ester (94-26-8) + 4-chloro-phenol (106-48-9) + N,N'-bis(2,6-diisopropylphenyl)-1,6,7,12-tetrachloroperylene-3,4:9,10-tetracarboxylic acid diimide (112078-00-9) → C77H63Cl3N2O10

Conditions	Yield
Stage #1: N,N'-bis(2,6-diisopropylphenyl)-1,6,7,12-tetrachloroperylene-3,4:9,10-tetracarboxylic acid diimide With potassium carbonate In 1-methyl-pyrrolidin-2-one at 120℃; for 2h; Stage #2: 4-hydroxybenzoic acid, butyl ester In 1-methyl-pyrrolidin-2-one at 120℃; for 1h; Stage #3: 4-chloro-phenol With potassium carbonate In 1-methyl-pyrrolidin-2-one for 4h;	68.7%
Stage #1: 4-hydroxybenzoic acid, butyl ester; N,N'-bis(2,6-diisopropylphenyl)-1,6,7,12-tetrachloroperylene-3,4:9,10-tetracarboxylic acid diimide With potassium carbonate In 1-methyl-pyrrolidin-2-one at 120℃; for 3h; Stage #2: 4-chloro-phenol In 1-methyl-pyrrolidin-2-one at 120℃; for 4h;	68.7%

tert.-butylhydroperoxide (75-91-2) + 4-hydroxybenzoic acid, butyl ester (94-26-8) → C15H22O5 (1285531-40-9)

Conditions	Yield
With dirhodium(II) tetrakis(caprolactam) In water; toluene at 40℃; for 3h; chemoselective reaction;	66%

4-hydroxybenzoic acid, butyl ester (94-26-8) → C66H78N3O18P3

Conditions	Yield
With potassium phosphate; 2,2,4,4,6,6-hexachloro-1,3,5-triaza-2,4,6-triphosphorine In acetonitrile for 10h; Heating;	65%

4-hydroxybenzoic acid, butyl ester (94-26-8) + 2-phenoxy-terephthaloyl dichloride → 3-(4-butoxycarbonylphenyloxycarbonyl)xanthen-9-one

Conditions	Yield
In pyridine Heating;	60%

4-hydroxybenzoic acid, butyl ester (94-26-8) + C50H36Cl8N10P6 → C138H140N10O24P6

Conditions	Yield
With potassium carbonate In tetrahydrofuran for 96h; Inert atmosphere; Cooling with ice; Reflux;	50%

1,4-dibromo-butane (110-52-1) + 4-hydroxybenzoic acid, butyl ester (94-26-8) → butyl 4-(4-bromobutoxy)benzoate + 1,4-bis(4-butylcarbonylphenyloxy)butane

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 20℃; Inert atmosphere;	A 25% B 43%

4-hydroxybenzoic acid, butyl ester (94-26-8) → butyl 4-[(aminosulphonyl)oxy]benzoate

Conditions	Yield
With sulphamoyl chloride; sodium hydride In N,N-dimethyl-formamide; toluene for 10h; Heating;	25%
Stage #1: 4-hydroxybenzoic acid, butyl ester With sodium hydride In N,N-dimethyl-formamide at 0℃; Stage #2: With sulphamoyl chloride In N,N-dimethyl-formamide; toluene
Stage #1: 4-hydroxybenzoic acid, butyl ester With sodium hydride In N,N-dimethyl-formamide at 0℃; for 0.5h; Stage #2: With sulphamoyl chloride In N,N-dimethyl-formamide; toluene for 10h;

4-hydroxybenzoic acid, butyl ester (94-26-8) + 3-nitrobenzene-1,2-dicarbonitrile (51762-67-5) + zinc diacetate (557-34-6) + water (7732-18-5) → tetrakis (4-carboxylphenoxy) phthalocyaninezinc

Conditions	Yield
Stage #1: 4-hydroxybenzoic acid, butyl ester; 3-nitrobenzene-1,2-dicarbonitrile With potassium carbonate In dimethyl sulfoxide Stage #2: zinc diacetate With 1,8-diazabicyclo[5.4.0]undec-7-ene Stage #3: water	22.5%

4-hydroxybenzoic acid, butyl ester (94-26-8) → butyl 4-((2,4,4,6,6-pentachloro-1,3,5,2λ5,4λ5,6λ5-triazatriphosphinin-2-yl)oxy)benzoate

Conditions	Yield
With 2,2,4,4,6,6-hexachloro-1,3,5-triaza-2,4,6-triphosphorine; sodium hydride In tetrahydrofuran at 20℃; for 72h; Inert atmosphere; Cooling with ice;	20%

4-hydroxybenzoic acid, butyl ester (94-26-8) + phthalocyanine silicon(IV) dichloride (19333-10-9) → C54H42N8O6Si

Conditions	Yield
With pyridine In toluene for 48h; Reflux;	13.5%

1-bromo-butane (109-65-9) + 4-hydroxybenzoic acid, butyl ester (94-26-8) → n-butyl 4-n-butoxybenzoate (4906-27-8)

Conditions	Yield
With potassium hydroxide

phosgene (75-44-5) + 4-hydroxybenzoic acid, butyl ester (94-26-8) → 4-chlorocarbonyloxy-benzoic acid butyl ester (857538-41-1)

Conditions	Yield
With N,N-dimethyl-aniline; benzene

4-hydroxybenzoic acid, butyl ester (94-26-8) + benzenediazonium (2684-02-8) → 4-hydroxy-3-phenylazo-benzoic acid butyl ester

Conditions	Yield
With sodium hydroxide

Upstream product

• 71-36-3 butan-1-ol 
• 99-96-7 4-hydroxy-benzoic acid 
• 124-38-9 carbon dioxide 
• 16909-23-2 tetra-n-butylammonium phenolate 
• 106-41-2 4-bromo-phenol 
• 99-76-3 methyl 4-hydroxylbenzoate 
• 109-69-3 n-Butyl chloride 
• 1286216-54-3 1-ethyl-3-methylimidazolium 4-hydroxybenzoate 
• 123-08-0 4-hydroxy-benzaldehyde 
• 56-23-5 tetrachloromethane 
• 108-95-2 phenol 
• 619-57-8 p-hydroxybenzamide 
• 37170-50-6 di(methyl)tert-butyl(n-butoxy)silane 
• 251640-53-6 n-butyl 4-(methoxymethoxy)benzoate 

Downstream Products

• 4906-27-8 n-butyl 4-n-butoxybenzoate 
• 857538-41-1 4-chlorocarbonyloxy-benzoic acid butyl ester 
• 101745-75-9 4-(2-diethylamino-ethoxy)-benzoic acid butyl ester 
• 52791-73-8 4-hydroxy-3-nitro-benzoic acid butyl ester 
• 37470-61-4 butyl 3-bromo-4-hydroxybenzoate 
• 75254-69-2 butyl 3,5-di-bromo-4-hydroxybenzoate 
• 51-38-7 butyl 3,5-di-iodo-4-hydroxybenzoate 
• 723759-26-0 DCW234 
• 36457-18-8 4-(2-hydroxy-ethoxy)-benzoic acid butyl ester 
• 121970-17-0 4-(tetra-O-acetyl-β-D-glucopyranosyloxy)-benzoic acid butyl ester 
• 101256-53-5 4-hydroxy-3-morpholin-4-ylmethyl-benzoic acid butyl ester 

Relevant articles and documents

A novel way to prepare n-butylparaben under microwave irradiation

The synthesis of n-butylparaben under microwave irradiation in the presence of an inorganic salt ZnCl2 as a catalyst is reported. Using this specific catalyst for the synthesis of the n-butylparaben under microwave irradiation, not only shortens the reaction time, but also reduces the pollution from the use of concentrated sulfuric acid and prevents the complicated after-treatment handling problems. The reason for this type of microwave-assisted reaction is also demonstrated from the temperature profiles of the reaction. The ratio of the reactants for the better microwave energy efficiency is discussed. The use of microwave irradiation for the large-scale production of this type of food preservative is therefore feasible.

Zr-MOF-808 as Catalyst for Amide Esterification

In this work, zirconium-based metal–organic framework Zr-MOF-808-P has been found to be an efficient and versatile catalyst for amide esterification. Comparing with previously reported homogeneous and heterogeneous catalysts, Zr-MOF-808-P can promote the reaction for a wide range of primary, secondary and tertiary amides with n-butanol as nucleophilic agent. Different alcohols have been employed in amide esterification with quantitative yields. Moreover, the catalyst acts as a heterogeneous catalyst and could be reused for at least five consecutive cycles. The amide esterification mechanism has been studied on the Zr-MOF-808 at molecular level by in situ FTIR spectroscopic technique and kinetic study.

A recyclable cucurbit[6]uril-supported silicotungstic acid catalyst used in the esterification reaction

The esterification reaction used to prepare butyl paraben (BP) and propyl gallate (PG) catalyzed using a cucurbit[6]uril-supported Keggin-type silicotungstic acid (Q[6]-STA) catalyst has been investigated. The Q[6]-STA catalyst has been characterized using FTIR spectroscopy, XRD, SEM, EDS, thermal analysis, and surface area studies. Q[6]-STA was easy to prepare in high yield and exhibited some advantageous properties, such as high catalytic activity and its convenient recovery. Moreover, a reusability study showed that the Q[6]-STA catalyst was stable and active.

Method for preparing paraben

The invention discloses a method for preparing paraben. The method comprises the following steps: adding p-hydroxybenzoic acid (Amol), an alcohol (Bmol) and a benzimidazole ionic liquid (Cmol) into adry three-neck flask, slowly heating, carrying out reflux reaction, and carrying out TLC monitoring until reaction is finished; carrying out reduced pressure distillation to remove a solvent, washingresidues with ethyl acetate, carrying out suction filtration, and carrying out spin-drying on an obtained filtrate to obtain paraben. The yield can reach 90% or above; an obtained filter cake is the benzimidazole ionic liquid and can be recycled; the ratio of A to B to C is 1: 5: (0.2-0.5). The method provided by the invention has the advantages that the catalyst can be recycled, green and environment-friendly effects are realized, the cost is reduced, and the method is an efficient method for synthesizing paraben.

Proline ionic liquid and method for catalyzing synthesis of paraben by proline ionic liquid

The invention discloses proline ionic liquid and a method for catalyzing synthesis of paraben by the proline ionic liquid. The preparation method comprises the following steps: adding N-butylbenzimidazole, a solvent and proline into a dry three-neck flask, carrying out reflux reaction until the reaction is complete (monitored by TLC), evaporating to remove the solvent to obtain a faint yellow oilyliquid, namely the proline ionic liquid, adding p-hydroxybenzoic acid, alcohol and a proline ionic liquid into a dry three-necked bottle, heating to reflux reaction, monitoring by TLC until the reaction is finished, evaporating under reduced pressure to remove the solvent, extracting residues with diethyl ether, evaporating the diethyl ether phase to remove the solvent to obtain the methylparabenwith the yield of 88% or above, wherein the remainder is the ionic liquid, and carrying out washing and drying so that the product can be recycled for many times. The method disclosed by the invention is efficient, environment-friendly and safe, the catalyst can be recycled, the cost is reduced, the requirement on equipment is low, and the method is an efficient method for synthesizing paraben.

Novel Benzothiazole Ionic Liquids as Catalysts for the Synthesis of Parabens

Abstract: A simple and green approach to the esterification of p-hydroxybenzoic acid and aliphatic alcohols to obtain parabens was developed. First, two novel benzothiazole ionic liquids [HBth]H2PW12O40 (IL1) and [HBth]H4PMo12O41 (IL2) were synthesized with benzothiazole and heteropolyacids as starting materials. The synthesized ionic liquids were characterized by FTIR spectroscopy, TGA, PXRD analysis, and SEM. The application of IL1 and IL2 as catalysts for the synthesis of parabens was explored. The results showed that the ILs had a high catalytic activity in the synthesis of parabens, and, at the same time, they could be easily recovered and reused five times without loss of activity.

Method for preparing parabens

The invention discloses a method for preparing parabens. The method comprises the following steps: adding an appropriate amount of methanol (A) into a reaction container, sequentially adding a benzothiazole ionic liquid (B) and p-hydroxybenzoic acid (C) while stirring, slowly heating the obtained solution to a reflux temperature, and carrying out TLC monitoring until the reaction ends; and distilling off methanol, washing the obtained reaction product with ethyl acetate, carrying out suction filtration (the filter cake is the benzothiazole ionic liquid), carrying out rotary evaporation on thefiltrate, washing the product with water, carrying out suction filtration, and drying the product to obtain colorless crystals (methylparaben) at a yield of 91% or above. A ratio of A:B:C is 1:4:0.15, and a catalyst has a high activity and a good stability, and can be recycled. Additionally, the method also has a high esterification rate of 87%% or above to other parabens (ethylparaben, propylparaben, isopropylparaben, butylparaben and n-dodecyl 4-hydroxybenzoate), and provides a good method for industrial synthesis of parabens.

A process for preparing Nepal jin zhi method (by machine translation)

The invention discloses a method for preparing Nepal jin zhi method: in a reaction container by adding of formula choline chloride (Amol) and methanesulfonic acid (Bmol), for 80 °C stirring to complete dissolution shall be low altogether [...]; cooling to room temperature, then added to the hydroxy benzoic acid of formula (Cmol) acrylic (Dmol), slow heating, reflux reaction, TLC monitoring until a reaction is finished (1 - 2 h); reaction liquid-cooled to the room temperature, precipitate solid, filtered, cake of a small amount of washing, get [...], a yield of 90% or more; recycling the filtrate to obtain low altogether [...]. Wherein A: B: C: D is 1: (1 - 4): 1: (1.1 - 1.5). The method of the invention short reaction time, efficiency is high, the catalyst can be recycled, environmental protection, and reducing the cost; to reduce the consumption of the stinging; low requirements on equipment, is an efficient method of synthesizing [...]. (by machine translation)

Single-Step Dual Functionalization: One-Pot Bromination-Cross-Dehydrogenative Esterification of Hydroxy Benzaldehydes with CCl 3 Br - A Comparison with Selectfluor

Bromination of phenolic compounds without directly using molecular bromine possesses much importance. In this article an Ir III /CCl 3 Br-assisted single-step double functionalization of hydroxy benzaldehydes is reported. It involves simultaneous esterification of the aldehyde group and bromination of the aryl ring of phenolic aldehydes in one-pot. The reaction proceeds under mild conditions in the presence of 445 nm blue LED light to obtain highly functionalized bromo hydroxy benzoates in moderate to good yields. In comparison, Selectfluor as an oxidant gives only non-bromo phenolic esters.

Synthesis of Hydroxybenzoic Acids and Their Esters by Reaction of Phenols with Carbon Tetrachloride and Alcohols in the Presence of Iron Catalysts

Alkyl esters of hydroxy-, methoxy-, and ethoxybenzoic and cresotic acids have been synthesized by reaction of phenols, anisole, phenetole, and cresols with carbon tetrachloride and alcohols in the presence of iron catalysts.