The present disclosure provides, inter alia, methods for preparing formaldehyde from carbon dioxide using bis(silyl)acetals, methods for incorporating carbon derived from carbon dioxide into a complex organic molecule derived from formaldehyde using bis(silyl)acetals, and methods for generating an isotopologue of a complex organic molecule derived from formaldehyde using bis(silyl)acetals.

A process for recovering methacrolein and methanol from methacrolein dimethyl acetal. The method comprises a step of contacting a mixture comprising methyl methacrylate and methacrolein dimethyl acetal with a strong acid ion exchange resin in the presence of water. The mixture comprises no more than 0.2 wt % sodium methacrylate.

A process for recovering methacrolein and methanol from methacrolein dimethyl acetal. The method comprises a step of contacting a mixture comprising methyl methacrylate and methacrolein dimethyl acetal with a strong acid ion exchange resin in the presence of water. The mixture comprises no more than 0.2 wt % sodium methacrylate.

A process for preparing 4-penten-2-ynal of the following formula (2):

CH.sub.2CHCCCHO(2)

the process comprising a step of hydrolyzing a 5,5-dialkoxy-1-penten-3-yne compound of the following general formula (1):

CH.sub.2CHCCCH(OR.sup.1)(OR.sup.2)(1)

wherein R.sup.1 and R.sup.2 represent, independently of each other, a monovalent hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 8, more preferably 1 to 4, or R.sup.1 and R.sup.2 may be bonded to each other to form a divalent hydrocarbon group, R.sup.1-R.sup.2, having from 2 to 10 carbon atoms,
to obtain 4-penten-2-ynal (2).

##STR00001##

A process for preparing 4-penten-2-ynal of the following formula (2):

CH.sub.2CHCCCHO(2)

the process comprising a step of hydrolyzing a 5,5-dialkoxy-1-penten-3-yne compound of the following general formula (1):

CH.sub.2CHCCCH(OR.sup.1)(OR.sup.2)(1)

wherein R.sup.1 and R.sup.2 represent, independently of each other, a monovalent hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 8, more preferably 1 to 4, or R.sup.1 and R.sup.2 may be bonded to each other to form a divalent hydrocarbon group, R.sup.1-R.sup.2, having from 2 to 10 carbon atoms,
to obtain 4-penten-2-ynal (2).

##STR00001##

A process for preparing a dienynal compound of the following general formula (2): CH.sub.2CHCCCHCH(CH.sub.2).sub.nCHO (2), wherein n represents an integer of 0 to 11, the process comprising a step of hydrolyzing a dialkoxyalkadienyne compound of the following general formula (1): CH.sub.2CHCCCHCH(CH.sub.2).sub.nCH(OR.sup.1)(OR.sup.2) (1) wherein R.sup.1 and R.sup.2 represent, independently of each other, a monovalent hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 8, mere preferably 1 to 4, or R.sup.1 and R.sup.2 may be bonded to each other to form a divalent hydrocarbon group, R.sup.1-R.sup.2, having from 2 to 10 carbon atoms, and n represents an integer of 0 to 11, to obtain the dienynal compound (2).

##STR00001##

A process for preparing a dienynal compound of the following general formula (2): CH.sub.2CHCCCHCH(CH.sub.2).sub.nCHO (2), wherein n represents an integer of 0 to 11, the process comprising a step of hydrolyzing a dialkoxyalkadienyne compound of the following general formula (1): CH.sub.2CHCCCHCH(CH.sub.2).sub.nCH(OR.sup.1)(OR.sup.2) (1) wherein R.sup.1 and R.sup.2 represent, independently of each other, a monovalent hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 8, mere preferably 1 to 4, or R.sup.1 and R.sup.2 may be bonded to each other to form a divalent hydrocarbon group, R.sup.1-R.sup.2, having from 2 to 10 carbon atoms, and n represents an integer of 0 to 11, to obtain the dienynal compound (2).

##STR00001##

Disclosed is a method for preparing a 2-fluoroacrylate, comprising the steps of: (1) mixing a vinyl ether having the structure of formula A with dichloromonofluoromethane to yield a substituted cyclopropane compound having the structure of formula B; (2) mixing the substituted cyclopropane compound having the structure of formula B with R.sup.2OH to yield an acetal product having the structure of formula C, followed by hydrolysis to yield 2-fluoroacrylaldehyde having the structure of formula D; or reacting the substituted cyclopropane compound having the structure of formula B with water to yield 2-fluoroacrylaldehyde having the structure of formula D via hydrolysis; (3) oxidizing 2-fluoroacrylaldehyde having the structure of formula D to yield 2-fluoroacrylic acid having the structure of formula E; and (4) mixing 2-fluoroacrylic acid having the structure of formula E with R.sup.3OH to yield a 2-fluoroacrylate having the structure of formula F.

Disclosed is a method for preparing a 2-fluoroacrylate, comprising the steps of: (1) mixing a vinyl ether having the structure of formula A with dichloromonofluoromethane to yield a substituted cyclopropane compound having the structure of formula B; (2) mixing the substituted cyclopropane compound having the structure of formula B with R.sup.2OH to yield an acetal product having the structure of formula C, followed by hydrolysis to yield 2-fluoroacrylaldehyde having the structure of formula D; or reacting the substituted cyclopropane compound having the structure of formula B with water to yield 2-fluoroacrylaldehyde having the structure of formula D via hydrolysis; (3) oxidizing 2-fluoroacrylaldehyde having the structure of formula D to yield 2-fluoroacrylic acid having the structure of formula E; and (4) mixing 2-fluoroacrylic acid having the structure of formula E with R.sup.3OH to yield a 2-fluoroacrylate having the structure of formula F.

The present disclosure provides, inter alia, methods for preparing formaldehyde from carbon dioxide using bis(silyl)acetals, methods for incorporating carbon derived from carbon dioxide into a complex organic molecule derived from formaldehyde using bis(silyl)acetals, and methods for generating an isotopologue of a complex organic molecule derived from formaldehyde using bis(silyl)acetals.